JP2016158122A - Control server, transfer system, and transfer method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a transmission delay due to the passing of a far route.SOLUTION: A control server controls a transfer device network connected to a router group comprising a plurality of transfer devices for transferring data, and executes grouping processing of each connection point into a plurality of groups on the basis of a priority set in each of a plurality of connection points within the transfer device network to which at least one of the plurality of transfer devices belongs; generation processing for generating route information for specifying a destination to which arrival is made from a transmission source via the transfer device network, a router for advertising the destination, and a connection point to which a transfer device connected to the router belongs in each grouped group; setting processing which undergoes setting in the plurality of transfer devices through a communication interface such that the plurality of transfer devices transfer data according to route information; and advertisement processing for advertising the route information to a router specified by the route information through the communication interface.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a control server, a transfer system, and a transfer method for controlling a transfer device network for transferring data.

  Due to network complications due to increased traffic, OPEX / CAPEX (Operating Expenditure / Capital Expenditure) of communication devices is increasing in carriers. Replacing an expensive router network with an inexpensive transfer device network is effective in reducing OPEX / CAPEX. Patent Document 1 has been proposed as a method of replacing a router network with a transfer device.

  The transmission system disclosed in Patent Document 1 is a transmission network communication path management that sets a plurality of transmission apparatuses that are components of a transmission network, a plurality of routers that perform communication via the transmission network, and a communication path between the plurality of transmission apparatuses. A server, a transmission network communication path DB for storing the set communication path, and a virtual router control server. When the router is connected to the transmission device, the router transmits control data to the virtual router control server via the connected transmission device. The virtual router control server acquires information on the connection relationship between the newly connected router and the transmission device from the control data, and between the acquired information and the transmission device stored in the transmission network communication path DB. Based on the communication path information, a communication path between routers is established.

JP 2013-26829 A

  When a network is configured using a plurality of routers, a route is selected by each router performing calculations in a distributed manner using a routing protocol. For example, an IP network possessed by an ISP (Internet Service Provider) is generally composed of a plurality of routers. An ISP network exists in a wide area, and routers are installed across a plurality of areas. By making an appropriate setting for each router, it is possible to configure an IP network that allows packets to be transferred efficiently.

  For example, when transferring to a different area, it may be possible to pass through a long-distance line or a line installed on the seabed, which has high equipment costs and management costs, and the use of such a line should be avoided as much as possible. Therefore, when there are a plurality of routers that can be transferred to a router outside the ISP network when delivering the packet from the ISP network to a certain destination, the packets that have entered the ISP network from a certain router are the same if possible. In many cases, a network that exits the ISP network through a router existing in a region is designed.

  When centralized control is performed using a wide area network such as an ISP network as a single router as in the transmission system of Patent Document 1, the output of the transfer device existing at the boundary between the centralized network and the other network The port seems to correspond to the network interface of one router, and the transfer device exists in a wide area.

  At this time, it is assumed that there are several other output ports from which the packet to the destination can be output by determining one packet output destination for the packet to the destination by the optimum route calculation of the router. Is output to the outside of the ISP network through the determined packet output port. At this time, when a packet is transferred from another transfer device located far away from the transfer device having the output port determined as the output destination, a transmission delay occurs due to passing through a far route. Become.

  An object of the present invention is to suppress transmission delay caused by passing through a far route.

  A control server according to one aspect of the invention disclosed in the present application is a control server configured to control a transfer device network configured by a plurality of transfer devices that transfer data and connected to a router group, and the control server includes a program And a communication interface for communicating with the router group via the plurality of transfer devices and the plurality of transfer devices, and the processor includes the plurality of transfer devices. Grouping processing for grouping each connection point into a plurality of groups based on the priority set for each of the plurality of connection points in the transfer apparatus network to which at least one of the group belongs, and the grouping For each group grouped by processing, a destination reached from the transmission source via the transfer device network, and A generation process for generating path information for specifying a router that advertises the destination and a connection point to which a transfer apparatus connected to the router belongs, and path information generated by the plurality of transfer apparatuses by the generation process A setting process for setting the plurality of transfer devices via the communication interface so as to transfer data according to the information, and an advertisement process for advertising the route information to the router specified by the route information via the communication interface And executing.

  According to the exemplary embodiment of the present invention, it is possible to suppress transmission delay due to passing through a far route. Problems, configurations, and effects other than those described above will become apparent from the description of the following embodiments.

It is explanatory drawing which shows the system configuration example and data transfer example of the transfer system concerning a present Example. It is a block diagram which shows the structural example of a transfer apparatus. It is explanatory drawing which shows the example of the memory content of an input transfer table. It is explanatory drawing which shows the example of the memory content of a label transfer table. It is explanatory drawing which shows the example of the memory content of an output transfer table. It is a block diagram which shows the structural example of a control server. It is explanatory drawing which shows the example of the memory content of the path | route information table stored in the memory | storage part. It is explanatory drawing which shows the memory content example 1 of a difference path | route information table. It is explanatory drawing which shows the memory content example 2 of a difference path | route information table. It is explanatory drawing which shows the memory content example 3 of a difference path | route information table. It is explanatory drawing which shows the memory content example 1 of the routing information database classified by group. It is explanatory drawing which shows the example 2 of memory content of the route information database classified by group. It is explanatory drawing which shows the example 3 of memory content of the route information database classified by group. It is explanatory drawing which shows the example of the memory content of an adjacent router management table. It is explanatory drawing which shows the example of the memory content of a group information table. It is explanatory drawing which shows the example of the memory content of a PoP information table. It is explanatory drawing which shows the example of the memory content of a transfer apparatus information table. It is explanatory drawing which shows the example of the memory content of a physical link information table. It is explanatory drawing which shows the example of the memory content of a path management table. It is a flowchart which shows the detailed process sequence example of the grouping process (F2000) which a grouping process part performs. 17 is a flowchart showing a detailed processing procedure example of a PoP group distribution process (F2100) shown in FIG. 16. It is a flowchart which shows the detailed process sequence example of the routing information operation process by the grouping change which a virtual router management function part performs. FIG. 19 is a flowchart illustrating a detailed processing procedure example of a route information table change process (F2250) by grouping change illustrated in FIG. 18. FIG. 19 is a flowchart illustrating a detailed processing procedure example of the optimum route selection processing (F2300) illustrated in FIG. 18. 20 is a flowchart illustrating a detailed processing procedure example of the route information comparison processing (F2400) illustrated in FIG. 19. It is a flowchart which shows the detailed process sequence example of the difference path | route information table update process (F2500) shown in FIG. It is a flowchart which shows the example of a detailed process sequence of the difference acquisition process (F2550) shown in FIG. 19 is a flowchart illustrating a detailed processing procedure example of a transfer device setting process (F2600) illustrated in FIG. 18. It is a flowchart which shows the example of a detailed process sequence of the transfer apparatus setting object determination process (F3100). It is a flowchart which shows the detailed process sequence example of the input / output transfer table creation process (F3000) shown in FIG. It is a flowchart which shows the detailed process sequence example of the route information advertisement process (F2700) shown in FIG. It is a flowchart which shows the example of a detailed process sequence of the route advertisement process (F2900) by router connection. It is a flowchart which shows the detailed example of a process sequence of a new route acquisition process (F2800).

  In this embodiment, when a plurality of transfer devices are centrally controlled as a single router, the output port is not determined as a whole for a certain destination, and the packet input port is considered in consideration of the transfer device network. Allows packets to be sent through output ports that are close to each other. As a result, the packet is transferred through a path with a low cost value, and the packet is transferred as much as possible between the same transfer groups having a short distance between the transfer apparatuses. Therefore, the packet transfer time can be shortened and transmission delay can be suppressed. This also reduces the usage rate of long-distance links with high equipment costs and management costs, and it is possible to suppress the addition of long-distance links.

<System configuration example and data transfer example>
FIG. 1 is an explanatory diagram illustrating a system configuration example and a data transfer example of the transfer system 1 according to the present embodiment. In the following description, there are a plurality of transfer devices, routers, physical links, PoP (Point of Presence), and networks. However, in the case where they are not distinguished from each other, reference numerals 200, 300, 400, 500, It is generally named 600. On the other hand, when distinguishing each individual, for example, a uniquely identifiable code such as a transfer device 201 is used.

  In FIG. 1, the transfer system 1 includes a transfer device network 10 in which a plurality of transfer devices 200 are connected by physical links 400, and a control server 100 that controls the plurality of transfer devices 200. The transfer device 200 is connected to the control server 100 via a network different from the physical link 400. The transfer system 1 is a system capable of making the transfer device network 10 look like one router (virtual router 10) by centrally controlling a plurality of transfer devices 200 by the control server 100. The transfer device network 10 and the virtual router are synonymous. A plurality of routers 300 are connected to the transfer device network 10. The control server 100 and the transfer device 200 may be logically connected by, for example, a TCP (Transmission Control Protocol) / IP (Internet Protocol) protocol or the like.

  The transfer device network 10 includes two types of transfer devices 200, transfer devices 201 to 205 at the boundary with the network 600 and transfer devices 206 and 207 inside the transfer device network 10. Transfer apparatuses 201 to 205 at the boundary with the network 600 are connected to the router 300. The transfer apparatuses 201 to 205 at the boundary with the network 600 exist in the PoP 500 in the transfer apparatus network 10. The PoP 500 is an ISP facility and is a connection point between a device outside the transfer device network 10 and the transfer device network 10. The PoP 500 may include a plurality of transfer devices 200 like the PoP 504. In the transfer device 200, route information is set under the control of the control server 100. The route information is information used by the transfer device 200 when transferring a packet between the transfer devices 200 existing in the PoP 500.

  The networks F to J are physical links 400 that connect the router 300 and the transfer apparatus 200. The router 300 is also referred to as an “adjacent router” because it is directly connected to the transfer apparatuses 201 to 205 via the networks F to J that are the physical links 451 to 455.

  In the optimum route calculation of the router 300, the output port of a packet for a certain destination is determined as one. The optimum route refers to a route selected by the result of the route selection algorithm. Even if there are a plurality of other output ports that can output a packet to the destination, the packet is transmitted through the determined output port. For example, when the destination is the network B, a packet from the transmission source network D passes through the router 302 regardless of whether it passes through the router 301 or the router 305.

  That is, according to the optimum route calculation of each router 300, a packet transmitted from the network D to the network B via the router 301 is transmitted through the path P1 via the network F, the virtual router 10, the network G, and the router 302. Is done. In this case, in the virtual router 10, the packet passes through the transfer device 201, the transfer device 206, and the transfer device 202.

  A packet transmitted from the network D to the network B via the router 305 is transmitted through a path P 2 passing through the network J, the virtual router 10, the network G, and the router 302. In this case, in the virtual router 10, the packet passes through the transfer device 205, the transfer device 204, the transfer device 207, the transfer device 206, and the transfer device 202.

  The transfer devices 200 constituting the virtual router 10 are distributed in each area. As the path P2 has more transfer devices 200 to be relayed, the destination area is different from the transmission source area. Therefore, the path passes through a long-distance line or a line installed on the seabed, which has a high equipment cost and management cost. For example, in the path P2, when the physical link 405 between the transfer apparatuses 204 and 207 is an expensive long-distance line, a packet transmitted from the network D to the network B via the router 305 is transferred to the physical link 405. It is efficient to transmit without going through. In other words, it is efficient to transmit on the path P3 passing through the network J, the virtual router 10, the network I, and the router 304. In this case, in the virtual router 10, the packet passes through the transfer device 205 and the transfer device 204.

  In this embodiment, the control server 100 classifies the transfer device group into a plurality of groups based on the position information (PoP 500) where the transfer device 200 is arranged, and the transfer device group exists in the same group even if it is the same destination. Control to forward the packet.

  In grouping, the control server 100 sets a priority (PoP priority) for the PoP 500 and sets a high PoP priority for the important PoP 500 by an operation of the administrator. For example, an important PoP 500 that can reach many networks 600 such as PoP 500 connected to an international line is known. In the example of FIG. 1, since the PoPs 502 and 504 can reach many networks 600, the control server 100 sets a PoP priority higher than that of the other PoPs 500 for the PoPs 502 and 504 by the operation of the administrator. . As a result, a group centering on the important PoP 500 is created, and the grouping can be performed so that it can be output not from the PoP 500 far from the input PoP 500 but from the nearby PoP 500.

  In the case of FIG. 1, the transfer apparatuses 201 and 202 belong to the group 2, and the transfer apparatuses 203 to 205 belong to the group 1. Therefore, even if the destination is the same network B, the packet transferred from the router 305 passes through the transfer devices 205 and 204 belonging to the group 1 and does not pass through the group 2, but the router 304. To reach. That is, a packet passing from the network D via the router 305 reaches the network B not via the path P2 but via the path P3.

  Note that different transfer apparatuses 200 are connected by a physical link 400. There is a possibility that a relay device that amplifies the signal is included between the physical links 400. However, in the present embodiment, a physical link is simply used as long as the link is not related to the data transfer method between the transfer devices 200. Treat as 400.

<Configuration Example of Transfer Device 200>
FIG. 2 is a block diagram illustrating a configuration example of the transfer device 200. The transfer device 200 is, for example, an MPLS (Multi Protocol Label Switching) label switch, but it is only necessary that a path can be established between the transfer devices 200 connected to the adjacent router 300, and the transfer device 200 is an MPLS label switch. It is not limited.

  The transfer apparatus 200 includes an apparatus control unit 210, an input packet processing unit 220, an input transfer table 225, a label transfer processing unit 230, a label transfer table 235, an output packet processing unit 240, an output transfer table 245, A plurality of physical ports 250. Specifically, the device control unit 210, the input packet processing unit 220, the label transfer processing unit 230, and the output packet processing unit 240, for example, send a program stored in a storage device (not shown) to a processor (not shown). The function is realized by executing. Further, the device control unit 210, the input packet processing unit 220, the label transfer processing unit 230, and the output packet processing unit 240 are implemented by hardware by designing with an integrated circuit such as a field-programmable gate array (FPGA), for example. A function may be realized. Specifically, the input transfer table 225, the label transfer table 235, and the output transfer table 245 are realized by being stored in a storage device, for example. First, the input transfer table 225, the label transfer table 235, and the output transfer table 245 will be described.

  FIG. 3 is an explanatory diagram showing an example of the contents stored in the input transfer table 225. The input transfer table 225 is a table that stores information related to the transfer destination of the packet input to the transfer apparatus 200. The input transfer table 225 includes a port number 1301, a destination network 1302, an identification label 1303, and a transfer label 1304 as fields. A combination of values in the same row 1301 to 1304 constitutes an entry. Since the entry of the input transfer table 225 is set based on the route information calculated by the control server 100, the entry is an empty table until the control server 100 calculates the route information and the device control unit 210 performs the setting. . Note that the input transfer table 225 shown in FIGS. 3A and 3B is an input transfer table 225 set in the transfer apparatus 201.

  The port number 1301 is a field that stores the port number of the transfer apparatus 200 as a value. In this embodiment, the port number is expressed as two numbers with a slash between them, such as (2/1). The number on the left side of the slash is the number of the network interface card installed in the transfer device. The number on the right side of the slash is the number of the physical port belonging to the network interface card on the left side of the slash. For example, (2/1) means the physical port number 1 of the network interface number 2.

  The destination network 1302 is a field for storing a destination network address included in the input packet as a value. The identification label 1303 is a field for storing an MPLS label for identifying a path to be described later as a value. The transfer label 1304 is a field for storing information for identifying a transfer device to which a packet is transferred next.

  FIG. 4 is an explanatory diagram showing an example of the contents stored in the label transfer table 235. The label transfer table 235 is a table that stores information related to the transfer destination in the transfer device network 10 of the packet input to the transfer device 200, and is a table that is set in advance by the transfer device management unit 123 of the control server 100 described later. is there. (A) is a label transfer table 235 of the transfer apparatus 201. (B) is a label transfer table 235 of the transfer device 206. (C) is a label transfer table 235 of the transfer device 207. (D) is a label transfer table 235 of the transfer apparatus 202. (E) is a label transfer table 235 of the transfer device 203.

  The label transfer table 235 has, as fields, an input port 1351, an input transfer label 1352, an output transfer label 1353, and an output port 1354, and a combination of values in the same row of each field 1351-1354 constitutes an entry. To do. The input port 1351 is a field for storing a port number into which a packet is input as a value.

  The input transfer label 1352 is a field for storing the transfer label of the input packet as a value. The output transfer label 1353 is a field for storing the transfer label of the output packet as a value. The value of the input transfer label 1352 of the packet input from the input port 1351 is rewritten to the value of the output transfer label 1353 according to a rule described later. The output port 1354 is a field for storing a port number to which a packet is output as a value.

  FIG. 5 is an explanatory diagram showing an example of the contents stored in the output transfer table 245. The output transfer table 245 is a table that stores information related to the output destination of the packet input to the transfer device 200 outside the transfer device network 10, and includes, as fields, a destination network 1402, an identification label 1403, a transfer label 1404, It has a rewrite destination MAC (Media Access Control) 1405 and a rewrite source MAC 1406, and a combination of values in the same row of each field 1401-1405 constitutes an entry. The entries in the output transfer table 245 are set based on the route information calculated by the control server 100. Therefore, the entries are empty until the control server 100 calculates the route information and the device control unit 210 performs the setting. . (A) and (B) are the output transfer table 245 set in the transfer apparatus 202, and (C) is the output transfer table 245 set in the transfer apparatus 203.

  The destination network 1402 is a field that stores, as a value, a destination network address to which the output packet can be reached. The identification label 1403 is a field for storing an MPLS label for identifying a path to be described later. The transfer label 1404 is a field for storing information for identifying the transfer apparatus 200 to which the output packet is transferred next. The rewrite destination MAC 1405 is a field for storing a value of a MAC address to be rewritten when a process for rewriting a destination MAC address of a packet to be described later is performed. The rewrite transmission source MAC 1406 is a field for storing a value of a MAC address to be rewritten when performing a process of rewriting a transmission source MAC address of a packet to be described later.

  Returning to FIG. 2, the apparatus control unit 210 operates the input transfer table 225, the label transfer table 235, and the output transfer table 245 based on the packet received from the control server 100.

  The input packet processing unit 220 processes a packet input from the physical port 250. Specifically, for example, when an MPLS label is inserted in a packet input from the physical port 250, the input packet processing unit 220 transfers the packet to the label transfer processing unit 230 as it is. On the other hand, when the MPLS label is not inserted in the input packet, the input packet processing unit 220 refers to the input transfer table 225.

  The input packet processing unit 220 inputs an entry in which the port number of the port to which the packet is input matches the value of the port number 1301 and the destination network address included in the packet matches the value of the destination network 1302 Search from the transfer table 225. If there is a matching entry, the input packet processing unit 220 inserts the values of the identification label 1303 and the transfer label 1304 of the corresponding entry into the packet and passes them to the label transfer processing unit 230. Specifically, for example, the input packet processing unit 220 inserts the value of the identification label 1303 between the MAC header and the IP header of the packet. Further, the input packet processing unit 220 inserts the value of the transfer label 1304 between the MAC header and the value of the identification label 1303.

  In addition, the input packet processing unit 220 uses the value of the port number 1301 (input port) so that the label transfer processing unit 230 that processes the packet next can identify the port number at which the packet is input to the transfer apparatus 200. A header in which the number is recorded (referred to as “input port information header”) is inserted into the packet. The input port information header is information used only in the transfer apparatus 200, and has a fixed-length area in which a port number is entered. The configuration of the input port information header is not limited as long as the label transfer processing unit 230 can determine the input port number.

  The label transfer processing unit 230 processes the packet transferred from the input packet processing unit 220 with reference to the label transfer table 235. Specifically, the label transfer processing unit 230 matches the port number recorded in the input port information header of the packet transferred from the input packet processing unit 220 with the value of the input port 1351, and The label transfer table 235 is searched for an entry whose included transfer label matches the input transfer label 1352.

  If there is a matching entry, the label transfer processing unit 230 rewrites the transfer label number included in the packet to the value of the output transfer label 1353 of the entry. Then, the label transfer processing unit 230 removes the input port information header inserted into the packet by the input packet processing unit 220.

  Further, the label transfer processing unit 230 records the header (the output port number) in which the value of the output port 1354 (output port number) is recorded so that the output packet processing unit 240 that processes the packet next can identify the port number to output the packet. (Referred to as “output port information header”) is inserted into the packet. The output port information header is information used only in the transfer apparatus 200, and has a fixed-length area in which the port number is entered. The configuration of the output port information header is not limited as long as the output packet processing unit 240 can determine the output port number. The label transfer processing unit 230 passes the packet in which the output port information header is inserted to the output packet processing unit 240.

  The output packet processing unit 240 processes the packet transferred from the label transfer processing unit 230 with reference to the output transfer table 245. Specifically, the output packet processing unit 240 determines that the destination network address included in the packet matches the value of the destination network 1402, and the value of the identification label 1303 inserted by the input packet processing unit 220 is the value of the identification label 1403. , And the entry whose transfer label rewritten to the value of the output transfer label 1353 by the label transfer processing unit 230 matches the value of the transfer label 1404 is searched from the output transfer table 245.

  If there is a matching entry, the output packet processing unit 240 rewrites the destination MAC address of the packet received from the label transfer processing unit 230 to the value of the rewrite destination MAC 1405 of the entry. Subsequently, the output packet processing unit 240 rewrites the source MAC address of the packet whose destination MAC address has been rewritten to the value of the rewritten source MAC 1406, and removes the inserted identification label and transfer label. The output packet processing unit 240 refers to the port number recorded in the output port information header, removes the output port information header, and then outputs a packet from the referenced port number.

  If the packet received from the physical port 250 is a network control packet addressed to the virtual router 10, the input packet processing unit 220 transfers the packet to the control server 100. When the network control packet arrives at the transfer device 200 from the control server 100, the input packet processing unit 220 passes the packet to the output packet processing unit 240 through the label transfer processing unit 230. The network control packet is transmitted outside the transfer apparatus network 10 through the physical port 250 and transferred to the router 300.

<Configuration Example of Control Server 100>
FIG. 6 is a block diagram illustrating a configuration example of the control server 100. The control server 100 includes a processing unit 120 and a storage unit 140. The processing unit 120 refers to or updates a database or table in the storage unit 140. The processing unit 120 includes a packet transmission / reception unit 124, a virtual router function unit 121, a grouping processing unit 122, and a transfer device management unit 123. Specifically, the processing unit 120 realizes its function by causing a processor (not shown) to execute a program stored in a storage device (not shown), for example.

  The packet transmission / reception unit 124 receives a packet from the transfer device 200 via a port (not shown), analyzes the received packet, and distributes the analyzed packet to the virtual router function unit 121 or the transfer device management unit 123. For example, when the packet received from the transfer device 200 is a network control packet having IP routing protocol information such as BGP (Border Gateway Protocol), the packet transmitting / receiving unit 124 passes the packet to the virtual router function unit 121. When the packet received from the transfer device 200 is a transfer device control packet related to transfer device control such as information on the transfer device 200 or information on the physical link 400, the packet transmission / reception unit 124 sends information to the transfer device management unit 123. Pass the packet.

  The virtual router function unit 121 refers to or updates the path information table 141, the differential path information table 142, the group-specific path information database 143, and the adjacent router management table 144. The virtual router function unit 121 transmits and receives network control packets to and from the adjacent router 300, and sets the transfer apparatus network 10 to operate as one router. Specifically, the virtual router function unit 121 analyzes the network control packet received from the adjacent router 300. Then, the virtual router function unit 121 sets the transfer device network 10 to operate as one router when the network control packet is a control packet for establishing and maintaining an adjacency relationship or checking for survival between devices. .

  More specifically, the virtual router function unit 121 receives information on IP network addresses A to E advertised from the routers 301 to 305 to the network 600 in which each router 300 exists. The virtual router function unit 121 exchanges path information with a router existing in an AS other than the AS (Autonomous System) to which the virtual router function unit 121 belongs by using BGP. The route information advertised by the routers 301 to 305 to the virtual router function unit 121 is received by the transfer apparatuses 201 to 205 connected to the routers 301 to 305.

The route information received by the transfer apparatuses 201 to 205 is transferred to the control server 100, the packet transmission / reception unit 124 transfers it to the virtual router function unit 121, and the virtual router function unit 121 performs processing. The router 302 and the router 304 hold the route information of the network addresses A, B, and C, the router 301 and the router 305 hold the route information of the network address D, and the router 303 holds the route information of the network address E. . Until the grouping process is performed, the routers 301 to 305 and the transfer apparatuses 201 to 205 are not connected and route information is not exchanged.
Further, the route information advertised by the virtual router function unit 121 to the routers 301 to 305, that is, the route information advertised by the virtual router 10 is the transfer devices 201 to 205 in which the control server 100 is connected to the routers 301 to 305. And the transfer devices 201 to 205 transfer the data to the routers 301 to 305.

  The virtual router function unit 121 holds static route information and internal route information acquired by using IGP (Interior Gateway Protocol) such as OSPF (Open Shortest Path First) or IS-IS (Intermediate System to Intermediate System). The virtual router function unit 121 incorporates the internal route information into the BGP route, creates the route information table 141 as the BGP route information, and determines the optimum route using the information recorded in the route information table 141.

  Based on the information in the route information table 141, the virtual router function unit so that packets input from outside the transfer device network 10 to the transfer device network 10 reach the network recorded in the destination network 1101 of the route information table 141. 121 requests the apparatus control unit 210 of the transfer apparatus 200 existing in PoP to set the input transfer table 225 and the output transfer table 245. As a result, the input transfer table 225 and the output transfer table 245 are set in the transfer device 200. Packets input to the transfer device network 10 from outside the transfer device network 10 are transferred between the transfer devices set in advance by the transfer device 200 based on information in the input transfer table 225, the label transfer table 235, and the output transfer table 245. The packet is delivered to the path and transferred to a network outside the transfer device network 10 written in the destination network of the packet.

  The internal route information set in advance by the administrator in some way is taken into the route information table 141 as BGP route information. Further, the route information is compared based on the BGP path attribute, and the optimum route used for routing is determined.

  The router 300 holds route information for each routing protocol and static route information. When the same route information is received by each protocol, the router 300 selects route information having a high priority set according to the route acquisition method and the source protocol and sets it as the optimum route. Unlike normal router behavior, in this embodiment, the router 300 converts all route information into BGP route information and then compares the converted route information to determine the optimum route. In the present embodiment, the route selection procedure of the router 300 is described in a simplified manner, but an optimum route may be selected after a route table is divided for each protocol as in a normal router.

  When the route information is set in the route information table 141, the virtual router function unit 121, based on the contents of the set route information, refers to the input transfer table 225 and the output transfer table that the transfer device 200 refers to when transferring the packet. 245 entries are created. The virtual router function unit 121 transmits the created entries of the input transfer table 225 and the output transfer table 245 to the transfer apparatus 200 as route information set in the transfer apparatus 200.

  The transfer apparatus 200 sets the entries of the input transfer table 225 and the output transfer table 245 received from the control server 100 in the input transfer table 225 and the output transfer table 245. The transfer apparatus 200 can identify a path for transferring a packet by referring to the input transfer table 225 and the output transfer table 245 for the input packet. Since a path is set in advance between the router 300 and the transfer apparatus 200 connected to the router 300, the packet input to the transfer apparatus network 10 exists at the end of the set path. Transferred to the router 300. If the path set between the transfer devices 200 connected to the router 300 adjacent to the transfer device network 10 does not change the state of the transfer device network 10 such as a failure of the transfer device 200 or a broken physical link, Basically it is constant.

  The grouping processing unit 122 refers to or updates the group information table 145, the PoP information table 146, and the path management table 149. The grouping processing unit 122 divides the transfer device network 10 including a plurality of transfer devices 200 into one or more transfer groups based on information recorded in a PoP information table 146 described later. One or more PoPs belong to each forwarding group, and the virtual router function unit 121 has a different routing table for each forwarding group. In this embodiment, the route table of the router 300 is expressed in the group-specific route information database 143, and different packets are used depending on the transfer group to which the transfer device 200 to which a packet from the outside of the transfer device network 10 is input belongs. Transfer is performed.

  The transfer device management unit 123 refers to or updates the transfer device information table 147, the physical link information table 148, and the path management table 149. Also, the transfer device management unit 123 refers to the adjacent router management table 144. The transfer device management unit 123 monitors the state of a plurality of transfer devices 200, the physical link 400 connecting the transfer devices 200, and the logical path established between the transfer devices 200, and the transfer device 200 is set or a logical path is set. Further, the transfer device management unit 123 sets the label transfer table 235 in the transfer device 200.

The transfer device management unit 123 refers to the adjacent router management table 144 and creates paths for the number of entries. The transfer device management unit 123 determines the physical link 400 included in the path so as to minimize the sum of the inter-link distances of the included physical links 400, and establishes the path. As a method for creating a path that minimizes the distance between links, for example, an SPF (Shortest Path First) algorithm is employed. The transfer device management unit 123 creates a tree with the transfer device 200 at the endpoint that establishes the path as the root, the other transfer devices 200 as leaves, and the physical link 400 as a branch, and creates a path with the shortest cost according to the SPF algorithm. . The maximum value among integers not exceeding the distance between links is made to correspond to the cost of the branch.
Specifically, the storage unit 140 is realized by a storage device, for example. First, the table and database in the storage unit 140 will be described.

(Route information table)
FIG. 7 is an explanatory diagram showing an example of the stored contents of the route information table stored in the storage unit 140. The route information table 141 is a table that stores route information. As fields, the destination network 1101, the advertising source router 1102, the other path attribute 1103, the PoP priority 1104, the information source PoP 1105, and the information source group 1106 are stored. And a route acquisition source 1107, and a combination of values in the same row in each field 1101 to 1107 constitutes route information. The route information table 141 is a table created by the virtual router function unit 121.

  The destination network 1101 is a field for storing a destination network address that can be reached by the route information as a value. The advertisement source router 1102 indicates the identification number (router ID) of the router that advertised the route information to the virtual router function unit 121 as a value. The virtual router function unit 121 shows the transfer device network 10 as one virtual router 10 to the routers 301 to 305. The router ID of the virtual router 10 is ID: 10. The virtual router function unit 121 stores “10” in the advertisement source router 1102 if the router ID is obtained in the AS in which the transfer apparatus network 10 exists.

  The other path attribute 1103 is a field for storing other path attributes excluding a specific path attribute as a value. The other path attribute 1103 includes, for example, a LOCAL_PREF attribute indicating the priority of a route in one AS, and an AS_PATH attribute indicating an AS through which the route information has passed. The PoP priority 1104 is a field for storing the value of the PoP priority 852 set in the PoP to which the transfer apparatus 200 that has received the path information belongs. The PoP priority 852 is a field of the PoP information table 146 described later. In the PoP priority 1104, “−1” indicating undefined is recorded as the initial value of the priority before the grouping process.

  The information source PoP 1105 is a field that stores, as a value, the identification number of the PoP to which the transfer apparatus 200 that has received the path information belongs. The information source group 1106 is a field for storing, as a value, an identification number of a group to which the transfer apparatus 200 that has received the path information belongs. The route acquisition source 1107 is a field that stores, as a value, identification information of the transfer device 200 from which the virtual router function unit 121 acquired the route information and its port number. That is, the route acquisition source 1107 stores the identification information of the transfer apparatus 200 directly connected to the destination network 1101 and its port number as values. For example, like “201 (2/1)”, “201” on the left side is the identification information of the transfer apparatus 200, and (2/1) on the right side is the port number.

  The combination of the value of the destination network 1101 and the value of the route acquisition source 1107 identifies which port of which transfer device 200 is connected to which network 600. For example, in the entry 1151, the value of the destination network 1101 is “F”, and the value of the route acquisition source 1107 is “201 (2/1)”. Therefore, it can be seen that the port (2/1) of the transfer apparatus 201 is connected to the network F.

The group is not defined until the grouping process described later is performed. Therefore, “−1” indicating undefined is recorded in the information source group 1106 representing the identification number of the group to which the transfer apparatus 200 that has received the path information belongs, before the grouping process.
(A) is a path information table 141 before execution of a grouping process (F2000) described later, and (B) is a path information table after execution of a path information table change process (F2250) based on a grouping change described later. (C) is the route information table 141 after the route information is advertised from the adjacent router 300.

(Difference route information table)
FIG. 8 is an explanatory diagram of an example of the stored contents of the difference path information table. The difference path information table 142 is a table that stores difference path information. The differential path information is the entry shown in FIG. The entry corresponds to a remaining entry obtained by deleting an entry that matches the entry information of the old route information table by group 1050 from the entries of the current route information table by group 1000 shown in FIGS. 9A to 9C.

  The content of the difference path information table 142 is rewritten by the virtual router function unit 121. The differential route information table 142 is an empty table until the exchange of route information is completed. The differential path information table 142 includes, as fields, a destination network 1201, an advertisement source router 1202, another path attribute 1203, a PoP priority 1204, an information source PoP 1205, an old information source group 1206, and a current information source group 1207. And the route acquisition source 1208 and the deletion / update 1209, and the combination of the values in the same row of the fields 1201 to 1209 constitutes differential route information.

  The destination network 1201 is a field that stores a network address that can be reached by the differential path information as a value. The advertisement source router 1202 is a field that stores, as a value, the identification number of the router that advertised the differential route information to the virtual router function unit 121.

  The other path attribute 1203 includes values such as a priority and a weight excluding specific path attributes such as the PoP priority 1204, the information source PoP 1205, the old information source group 1206, the current information source group 1207, and the route acquisition source 1208. This field stores information. In BGP, the optimum route is determined by the path attribute. As the other path attribute 1203, either a LOCAL_PREF attribute indicating the priority of a route in one AS, an AS_PATH attribute indicating an AS through which the differential route information has passed, or the like is employed. The order in which BGP path attributes are compared is mentioned in RFC 1771, but is implementation-dependent. Therefore, in this embodiment, attention is paid to the PoP priority 1204, the information source PoP 1205, the old information source group 1206, the current information source group 1207, and the route acquisition source 1208, and the order in which other path attributes are compared is not particularly defined.

  The PoP priority 1204 is a field for storing the PoP priority set in the PoP 500 to which the transfer apparatus 200 that has received the differential path information belongs as a value. The information source PoP 1205 is a field that stores, as a value, identification information of the PoP 500 to which the transfer apparatus 200 that has received the differential path information belongs. The old information source group 1206 is a field for storing the identification number of the group to which the transfer apparatus 200 that has received the differential path information belongs as a value.

The current information source group 1207 is a field for storing the identification number of the group to which the transfer device 200 belongs when the differential path information is recorded as a value. The route acquisition source 1208 is a field for storing the identification information of the transfer device 200 that acquired the differential route information and the port number of the port of the transfer device 200 as values. The delete / update 1209 is a field in which “delete” or “update” is stored. “Delete” indicates that the differential route information is to be deleted, and “Update” indicates that the differential route information is to be updated.
8A shows the differential path information table 142 after execution of the differential path information table update process (F2500) in the path information operation process (F2200) based on grouping change described later, and FIG. 8B shows the path by router connection described later. FIG. 8C shows the difference path information table 142 after the execution of the difference path information table update process (F2500) in the advertisement process (F2900). FIG. 8C shows the difference path information table update process (F2500) in the new path acquisition process (F2800) described later. It is the difference path information table 142 after execution.

(Route information database by group)
9A to 9C are explanatory diagrams illustrating examples of stored contents of the group-specific route information database. The group-specific route information database 143 holds the route information applied to each group before and after performing the grouping process, and holds the route information applied to each group after the grouping process is performed. It is a database that stores an information table 1000 and a group-specific old route information table 1050 that holds route information applied to each group before performing grouping processing. The group route information database 143 is rewritten by the virtual router function unit 121.

  The group-by-group old route information table 1050 is a table that holds group-by-group route information (group-by-group old route information) before grouping or route information change is executed. The group-by-group current route information table 1000 is a table that holds group-by-group route information (group-by-group current route information) after grouping or route information change is executed. The group-by-group current route information table 1000 and the group-by-group old route information table 1050 are created by the virtual router function unit 121 based on the information in the route information table 141. Until a grouping process, which will be described later, is performed, no groups are defined. The group-specific current route information table 1000 and the group-based old route information table 1050 are initially empty tables with no entries.

  The group-specific current route information table 1000 includes, as fields, a use group 1001, a destination network 1002, an advertising source router 1003, another path attribute 1004, a PoP priority 1005, an information source PoP 1006, and an information source group 1007. , And a route acquisition source 1008, and a combination of values in the same row of each field 1001 to 1008 constitutes group current route information.

  The usage group 1001 is a field for storing the identification number of the current group that uses the entry as a value. The destination network 1002 is a field for storing a network address that can be reached by the current route information for each group as a value. The advertisement source router 1003 is a field for storing the identification number of the router 300 that has advertised the current route information for each group to the virtual router function unit 121 as a value. The other path attribute 1004 is a field for storing other path attributes excluding the specific path attribute described above as a value.

  The PoP priority 1005 is a field for storing the PoP priority set as the value in the PoP 500 to which the transfer apparatus 200 that has received the current routing information for each group belongs. The information source PoP 1006 is a field for storing, as a value, identification information of the PoP 500 to which the transfer apparatus 200 that has received the current route information for each group belongs. The information source group 1007 is a field for storing a group to which the transfer apparatus 200 that has received the current route information for each group belongs as a value. The route acquisition source 1008 is a field for storing the identification information of the transfer device 200 that acquired the current route information for each group and the port number of the port of the transfer device 200 as values.

  The group-based old route information table 1050 includes, as fields, a use group 1051, a destination network 1052, an advertisement source router 1053, another path attribute 1054, a PoP priority 1055, an information source PoP 1056, and an information source group 1057. , And a route acquisition source 1058, and a combination of values in the same row of each of the fields 1051 to 1058 constitutes group current route information.

  The usage group 1051 is a field for storing the identification number of the old group that uses the entry as a value. The destination network 1052 is a field for storing, as a value, a network address that can be reached by the old route information for each group. The advertisement source router 1053 is a field for storing the identification number of the router 300 that advertised the old route information for each group to the virtual router function unit 121 as a value. The other path attribute 1054 is a field for storing other path attributes excluding the specific path attribute described above as a value.

The PoP priority 1055 is a field for storing the PoP priority set as the value in the PoP 500 to which the transfer apparatus 200 that has received the old route information for each group belongs. The information source PoP 1056 is a field for storing, as a value, identification information of the PoP 500 to which the transfer apparatus 200 that has received the old route information for each group belongs. The information source group 1057 is a field for storing a group to which the transfer apparatus 200 that has received the old route information for each group belongs as a value. The route acquisition source 1058 is a field for storing the identification information of the transfer device 200 that acquired the old route information for each group and the port number of the port of the transfer device 200 as values.
9A and 9B show the update process of the group-specific route information database 143 by the optimum route selection process (F2300) described later, and FIG. 9C shows the optimum in the new route acquisition process (F2800) described later. It is the route information database 143 classified by group after route selection processing (F2300) execution.

(Adjacent router management table)
FIG. 10 is an explanatory diagram showing an example of the contents stored in the adjacent router management table 144. The adjacent router management table 144 is a table that stores information regarding the routers 301 to 305 connected to the transfer apparatus network 10. The information is registered in advance by the administrator. The adjacent router management table 144 is rewritten by the virtual router function unit 121. 10A shows the content before the router 300 is connected to the transfer device network 10, and FIG. 10B shows the content after the router 300 is connected to the transfer device network 10.

  The adjacent router management table 144 includes, as fields, an adjacent router ID 801, an adjacent router MAC 802, an adjacent router IP 803, a connection transfer device 804, a connection port MAC 805, a connection port IP 806, a connection PoP_ID 807, and a connection state 808. A combination of values in the same row of each field 801 to 808 constitutes an entry.

  The adjacent router ID 801 is a field for storing a number (adjacent router ID) for identifying the router 300 connected to the transfer apparatus network 10 as a value. The adjacent router MAC 802 is a field for storing a MAC address set in the network interface of the router 300 connected to the transfer apparatus network 10 as a value. Since the router 300 is not connected to the transfer device network 10 in the initial state, “BROADCAST” indicating a broadcast address is stored as a value until the router 300 is connected to the transfer device network 10 ((A)). reference). When the router 300 is connected to the transfer apparatus network 10, the virtual router function unit 121 acquires the MAC address set in the network interface of the adjacent router 300 by ARP resolution, and overwrites the adjacent router MAC 802.

  The adjacent router IP 803 is a field for storing, as a value, an IP address set in the network interface of the router 300 connected to the transfer apparatus network 10. The connection transfer device 804 is a field that stores the identification information of the transfer device 200 connected to the adjacent router 300 and its port number as values. The connection port MAC 805 is a field that stores the MAC address of the port of the transfer device 200 connected to the adjacent router 300 as a value. The transfer device network 10 looks like one router when viewed from the adjacent routers 301 to 305 connected thereto. For this reason, when viewed from the adjacent router 300, the value of the connection port MAC 805 looks like the MAC address of the connected virtual router 10.

  The connection port IP 806 is a field for storing the IP address of the virtual router 10 shown to the adjacent router 300 as a value. The connection port IP 806 is set as an IP address for communicating with the adjacent router 300. The network address corresponding to the IP address is recorded in the route information table 141. When advertising BGP route information to the neighboring router 300, the connection port IP806 is used as the source IP address of the packet sent to the neighboring router 300. Thereby, when viewed from the adjacent router 300, the connection transfer device 804 appears as a port of the virtual router 10.

  The connection PoP_ID 807 is a field for storing the identification information of the PoP 500 to which the connection transfer apparatus 804 belongs as a value. The connection state 808 is a field for storing information indicating the connection state between the transfer apparatus network 10 and the adjacent router 300 as a value. The information includes “communication enabled” and “communication disabled”. “Communication enabled” indicates that IP communication between the adjacent router 300 and the virtual router function unit 121 is possible. “Communication impossible” indicates that IP communication between the router 300 and the virtual router function unit 121 is impossible. Since the adjacent routers 301 to 305 and the transfer device network 10 are not connected in the initial state, the value of the connection state 808 is “communication impossible” (see (A)).

(Group information table)
FIG. 11 is an explanatory diagram showing an example of the contents stored in the group information table 145. The group information table 145 is a table that holds the PoP_ID of the PoP 500 belonging to each group divided by the grouping process. The group information table 145 has a group ID 951 and a belonging PoP list 952 as fields, and the fields 951 and 952 are the same. A combination of row values constitutes an entry. The group information table 145 is rewritten by the grouping processing unit 122.

The group ID 951 is a field for storing a transfer group identification number as a value. The belonging PoP list 952 is a field that stores, as values, one or more lists of PoP 500 belonging to the transfer group, that is, identification numbers of PoP 500 belonging to the transfer group.
(A) to (E) show the update process of the group information table 145 by the grouping process (F2000) described later.

(PoP information table)
FIG. 12 is an explanatory diagram showing an example of the contents stored in the PoP information table 146. The PoP information table 146 is a table that holds group ID information to which the PoP 500 belongs before and after the grouping process. The fields include PoP_ID 851, PoP priority 852, belonging transfer device list 853, old belonging group 854, current belonging group. And a group of values belonging to the same row in each of the fields 851 to 855 constitutes an entry. The PoP information table 146 is rewritten by the grouping processing unit 122.

  The PoP_ID 851 is a field that stores identification information of a plurality of PoPs 500. The PoP priority 852 is a field for storing a parameter used for performing transfer grouping, and the initial value is “0”. In FIG. 12A, the PoP priority 852 includes an entry in which an initial value other than 0 is input, which will be described later.

  The belonging transfer device list 853 is a field for storing one or more pieces of identification information of the transfer devices 200 existing in the PoP 500 identified by the PoP_ID 851. The former affiliation group 854 is a field for storing the number of the group to which the PoP 500 identified by the PoP_ID 851 belonged before grouping.

  The current affiliation group 855 is a field that stores the number of the group to which the PoP 500 identified by the PoP_ID 851 belongs after grouping. The old member group 854 and the current member group 855 are indefinite values before grouping, but if the PoP priority 852 is the initial value 0, there will be one transfer group as will be described later. The initial value of 854 and the current group 855 is “1”.

  When performing transfer grouping, the administrator sets a high priority for the important PoP 500 to the PoP priority 852, thereby creating a group centered on the PoP 500. As a result, transfer grouping is realized so that the output can be performed from a nearby PoP 500 instead of a remote PoP 500. The administrator knows an important PoP 500 that can reach many networks, for example, PoP 500 connected to an international line, and in FIG. 4 PoP 502, 504 can reach many networks 600, The administrator sets the PoP priority higher than the PoP 502 and 504 to the PoP priority 852.

Specifically, for example, the administrator sets the PoP priority 852 of the PoP 504 to “20”, the PoP priority 852 of the PoP 502 to “10”, and the PoP priority 852 of the other PoPs 501 and 503 to “0”. . The PoP priority 852 is set to a higher value for the important PoP500. In this embodiment, PoP 504 is higher in importance than PoP 502, and therefore PoP 504 is set to have a higher PoP priority 852 than PoP 502.
(A) and (B) show the update process of the PoP information table 146 by the grouping process (F2000) described later, and (C) shows the route information manipulation process (grouping change described later) ( F2200) The PoP information table 146 after execution.

(Transfer device information table)
FIG. 13 is an explanatory diagram of an example of the contents stored in the transfer device information table 147. The transfer device information table 147 is a table that holds information related to the PoP 500 to which the transfer device 200 belongs. The transfer device information table 147 includes a transfer device ID 901, PoP information 902, and port information 903 as fields, and the fields 901 to 903 are the same. A combination of row values constitutes an entry. The values of the fields 901 to 903 are preset by the administrator.

  The transfer device ID 901 is a field that stores identification information of the transfer device 200 as a value. The PoP information 902 is a field for storing the identification information of the PoP 500 to which the transfer apparatus 200 belongs as a value. There are also transfer devices 200 that are not included in the PoP 500, such as the transfer devices 206 and 207. In the entry of the transfer device 200 not included in the PoP 500, the PoP information 902 stores a number that is not used as PoP identification information, for example, “−1”. The port information 903 is a field for storing a port number included in the transfer apparatus 200 as a value.

(Physical link information table)
FIG. 14 is an explanatory diagram showing an example of the contents stored in the physical link information table 148. The physical link information table 148 is a table that holds information on the physical links 400 (401 to 406, 451 to 455). The physical link information table 148 has, as fields, a link ID 701, link end point device information 702, and an inter-link distance 703, and combinations of values in the same row of the fields 701 to 703 constitute an entry.

  The link ID 701 is a field that stores identification information of the physical link 400 as a value. The device information 702 of the link end point is a field that stores the port number of the port of the device (router 300, transfer device 200) connected to both ends of the physical link 400 as a value. The inter-link distance 703 is a field for storing the wiring length of the physical link 400. The link distance 703 is appropriately input by the administrator. When the end point of the physical link 400 is the router 300, it is not necessary to input the inter-link distance 703.

(Path management table)
FIG. 15 is an explanatory diagram of an example of the contents stored in the path management table 149. The path management table 149 is a table for managing paths. A path is a path between adjacent routers 300 via the virtual router 10. The path management table 149 includes, as fields, a path ID 751, a path endpoint transfer device list 752, a path endpoint router list 753, a configuration link 754, an inter-path cost 755, and a transfer label value list 756. A combination of values in the same row in the fields 751 to 756 constitutes an entry.

  The path ID 751 is a field for storing identification information (path ID) for specifying a path. The path endpoint transfer device list 752 is a field for storing identification information and port numbers of the transfer devices 200 existing at both ends of the path in the transfer device network 10. The path end point router list 753 is a field for storing identification information of the router 300 connected to the end point of the path. The configuration link 754 is a field for storing the identification number of the physical link 400 that is a physical line on the path.

  The inter-path cost 755 is a field for storing the cost value of the path. In this embodiment, for example, the total distance of the physical links 400 stored in the configuration link 754 is stored as the cost value. The transfer label value list 756 is a field for storing the identification information of the transfer device 200 shown in the path endpoint transfer device list 752 and the value of the MPLS label set to the port number. As a result, packets that should pass through the path are distinguished. The path endpoint transfer device list 752 stores two identification information of the transfer device 200 and its port number, and the transfer label value list 756 stores two MPLS label values. The two values recorded in the path endpoint transfer device list 752 and the transfer label value list 756 respectively correspond to the stored order.

  For example, the port number (2/1) of the transfer device 201 stored in the first path endpoint transfer device list 752 of the entry 775 contains the MPLS label stored in the first transfer label value list 756. The value “4001” corresponds. The port number (2/1) of the transfer device 202 stored in the second of the path endpoint transfer device list 752 of the entry 775 contains the MPLS label stored in the second of the transfer label value list 756. The value “4004” corresponds. An entry 775 with a path ID 751 value “601” corresponds to the path P1 in FIG. 1, an entry 781 with a path ID 751 value “607” corresponds to the path P2 in FIG. 1, and the path ID 751 value “ The entry 784 “610” corresponds to the path P3 in FIG.

<Transfer Control Processing by Control Server 100>
Next, transfer control processing by the control server 100 according to the present embodiment will be described. In the transfer control process, the control server 100 executes (1) grouping process, (2) route advertisement process by router connection, and (3) new route acquisition process.

  (1) In the grouping process, the grouping processing unit 122 groups the transfer devices 200 into transfer groups according to the PoP 500 as shown in FIG. The virtual router function unit 121 processes a BGP Open message with the routers 301 to 305. As a result, an eBGP adjacency relationship is established between the virtual router function unit 121 and the routers 301 to 305. When the eBGP adjacency relationship is established, the virtual router function unit 121 rewrites the connection state 808 of the entries 825 to 829 in the adjacent router management table 144 illustrated in FIG. As a result, the adjacent router management table 144 is in the state shown in FIG.

  (2) In the route advertisement processing by router connection, the virtual router function unit 121 holds (1) the route information table 141 in FIG. 7A for the routers 301 to 305 that have become eBGP adjacency in the grouping processing. The route information for the existing network addresses F to J is advertised. Further, the route information for the network addresses A to E of the adjacent routers 301 to 305 is advertised to the virtual router function unit 121.

  (3) In the new route acquisition process, the virtual router function unit 121 acquires a new route advertised by (2) route advertisement processing by router connection. Thereby, the transfer device 200 of each transfer group is set so that when a packet is input to the transfer device network 10, packet transfer is performed according to the group-specific current route information table 1000 of FIG. 9C. Therefore, packet transfer is performed according to the group-specific current route information table 1000 of FIG. 9C.

  Hereinafter, detailed processing procedure examples of the above-described (1) grouping processing, (2) route advertisement processing by router connection, and (3) new route acquisition processing will be described.

  (1) The state of each table before execution of the grouping process is as follows. The input transfer table 225 shown in FIG. 3 and the output transfer table 245 shown in FIG. 5 are empty. The label transfer table 235 of the transfer device 200 has the contents shown in FIG. The route information table 141 shown in FIG. 7 has the contents shown in FIG. The difference path information table 142 shown in FIG. 8 is empty. The group current route information table 1000 and the group old route information table 1050 included in the group route information database 143 are empty (FIG. 9A).

  The adjacent router management table 144 shown in FIG. 10 has the contents shown in FIG. The group information table 145 shown in FIG. 11 has the contents shown in FIG. Note that (1) the entry may remain because it is initialized in the grouping process. The PoP information table 146 shown in FIG. 12 has the contents shown in FIG. In FIG. 12A, entries 875-878 are sorted in descending order of PoP priority 852, but (1) the order of entries 875-878 does not matter before the grouping process is executed. The transfer device information table 147 has the contents shown in FIG. The physical link information table 148 has the contents shown in FIG. The path management table 149 has the contents shown in FIG.

<(1) Grouping process>
FIG. 16 is a flowchart illustrating a detailed processing procedure example of the grouping processing (F2000) executed by the grouping processing unit 122. The grouping process (F2000) is executed when the PoP priority is changed. The PoP priority may be changed by an administrator, or may be automatically changed according to a change in system status. The case where the PoP priority is automatically changed will be described later. The grouping processing unit 122 deletes all entries in the group information table 145 (F2004). The group information table 145 is in the state shown in FIG.

  Next, the grouping processing unit 122 substitutes 0 for the variable GROUP_NUM (F2008). The variable GROUP_NUM is a variable corresponding to the group ID 951 of the group information table 145. Next, as shown in FIG. 12A, the grouping processing unit 122 sorts the PoP information table 146 in descending order of the PoP priority 852 (F2012). When there are a plurality of entries having the same value of the PoP priority 852, the entries having the same value of the PoP priority 852 are sorted in the ascending order of PoP_ID.

  Next, the grouping processing unit 122 substitutes 1 for the loop counter i (F2016). The loop counter i is a variable that identifies an entry in the PoP information table 146 to be processed. When i = 1, the first entry 878 is a processing target. Next, the grouping processing unit 122 determines whether or not the loop counter i is equal to or less than the number of entries in the PoP information table 146 (F2020). In the example of FIG. 12A, the number of entries in the PoP information table 146 is “4”. When the loop counter i is equal to or smaller than the number of entries in the PoP information table 146 (F2020: Yes), the process proceeds to F2024. On the other hand, if the loop counter i is not less than the number of entries in the PoP information table 146 (F2020: No), the grouping processing unit 122 ends the grouping process (F2000) because there is no entry to be processed. To do.

  In the example of FIG. 12A, the maximum value of the loop counter i is “4”. When i = 1, the entry 878 is selected as a processing target, and when i = 2, the entry 876 is selected. When i = 3, entry 875 is selected, and when i = 4, entry 877 is selected. When i = 5, it is not less than the number of entries (F2020: No), so there is no entry to be processed. Thereby, the grouping process part 122 complete | finishes a grouping process (F2000).

  In the case of F2020: Yes, the grouping processing unit 122 determines whether the value of the PoP priority 852 is larger than a predetermined value (“0” as an example in this embodiment) in the i-th entry of the PoP information table 146. Judgment is made (F2024). That is, the grouping processing unit 122 determines whether or not the i-th entry to be processed is a PoP that should be prioritized. When the value of the PoP priority 852 is larger than “0” (F2024: Yes), the i-th entry is determined as the PoP to be prioritized, and the process proceeds to F2040. On the other hand, when the value of the PoP priority 852 is not greater than 0 (F2024: No), the process proceeds to F2028.

  In the example of FIG. 12A, F2040 is executed for entry 878 when i = 1, F2040 is executed for entry 876 when i = 2, and F2028 is executed for entry 875 when i = 3. When i = 4, F2028 is executed for the entry 877.

  In the case of F2024: Yes, the grouping processing unit 122 increments the variable GROUP_NUM by 1 (F2040). Thereby, the value of the group ID 951 of the group to which the PoP 500 specified by the i-th entry belongs is determined. Next, the grouping processing unit 122 sets the variable GROUP_NUM for the group ID 951 in the group information table 145, and sets the value of the PoP_ID 851 of the i-th entry in the PoP information table 146 in the belonging PoP list 952 (F2044).

  Since variable GROUP_NUM = 1 when i = 1 (F2040), the group to which the PoP 504 identified by PoP_ID 851 in the entry 878 when i = 1 is group 1. Therefore, the grouping processing unit 122 creates the entry 601 in the group information table 145 shown in FIG. 11A, sets the value “1” of the variable GROUP_NUM to the group ID 951 of the entry 601, and belongs to the belonging PoP list. “504” is set to 952 (F2044). As a result, the group information table 145 has the contents from (A) to (B) in FIG.

  Since variable GROUP_NUM = 2 when i = 2 (F2040), the group to which the PoP 502 identified by the PoP_ID 851 in the entry 876 when i = 2 is group 2. Therefore, the grouping processing unit 122 creates the entry 602 in the group information table 145 shown in FIG. 11B, sets the value “2” of the variable GROUP_NUM in the group ID 951 of the entry 602, and belongs to the belonging PoP list. “502” is set to 952 (F2044). Thereby, the group information table 145 has the contents from (B) to (C) in FIG.

  Next, the grouping processing unit 122 substitutes the value of the current group 855 for the old group 854 in the i-th entry of the PoP information table 146 shown in FIG. The variable GROUP_NUM is substituted (F2048). The initial value of the former affiliation group 854 and the current affiliation group 855 is “1”. In the entry 878 when i = 1, the value “1” of the former member group 854 is overwritten with the value “1” of the current member group 855, and the value “1” of the current member group 855 is changed to a variable in the current member group 855. GROUP_NUM “1” is overwritten. In the entry 876 when i = 2, the value “1” of the former member group 854 is overwritten with the value “1” of the current member group 855, and the value “1” of the current member group 855 is changed to a variable in the current member group 855. “2” that is GROUP_NUM is overwritten (see FIG. 12B). Next, the grouping processing unit 122 increments the loop counter i by 1 (F2052), and returns to F2020.

  In the case of F2024: No, the grouping processing unit 122 determines whether or not the variable GROUP_NUM is smaller than 1 (F2028). That is, the grouping processing unit 122 determines whether the number of entries in the group information table 145 is 0 or 1 or more, in other words, whether the number of generated groups is 0 or 1 or more. In the PoP information table 146, if the number of entries whose PoP priority 852 is greater than 0 is 1 or more (F2028: No), F2100 is executed, and the number of entries whose PoP priority 852 is greater than 0 is 0. For example, when (F2028: Yes), that is, when the value of the PoP priority 852 of all entries in the group information table 145 of FIG. 12 is “0”, F2032 is executed.

  In the case of FIG. 12, the number of entries with a PoP priority 852 value greater than 0 is “2”. That is, when F2028 is executed for entry 875 when i = 3 and entry 877 when i = 4, the value of variable GROUP_NUM is already “2”. Therefore, when i = 3, 4, the grouping processing unit 122 executes the PoP group distribution process (F2100) because the value of the variable GROUP_NUM is “2” (F2028: No).

  In the case of F2028: No, the grouping processing unit 122 executes PoP group distribution processing (F2100). The group distribution process (F2100) of the PoP 500 is executed with the i-th entry as an argument. The group distribution process (F2100) of the PoP 500 is a process of causing the PoP 500, to which no group belongs at this time, belongs to a group that is close to the PoP 500 in terms of distance. Details of the group distribution process (F2100) of the PoP 500 will be described later with reference to FIG. After the group distribution process of PoP500 (F2100), the grouping processing unit 122 increments the loop counter i by 1 (F2056) and returns to F2020.

  In the case of F2028: Yes, the grouping processing unit 122 sets “1” in the group ID 951 in the group information table 145, and sets the value of the PoP_ID 851 of all entries in the PoP information table 146 in the belonging PoP list 952. (F2032).

  Next, the grouping processing unit 122 substitutes the value of the current affiliation group 855 for the old affiliation group 854 and assigns “1” to the current affiliation group 855 in all entries of the PoP information table 146 (F2036). Accordingly, when the value of the PoP priority 852 of all the entries in the group information table 145 of FIG. 12 is “0”, the PoP 500 of all the entries belongs to one group of group ID: 1. Thereby, the grouping process part 122 complete | finishes a grouping process (F2000).

(PoP group distribution process)
FIG. 17 is a flowchart illustrating a detailed processing procedure example of the group distribution processing (F2100) of the PoP 500 illustrated in FIG. The PoP 500 group distribution process (F2100) uses the i-th entry of the PoP information table as an argument. In the example of FIG. 12, entries 875 and 877 after i = 3 in which the value of the PoP priority 852 is “0” are processed. The group information table 145 is in the state shown in FIG. 11C when i = 3, and in the state shown in FIG. 11D when i = 4.

  The grouping processing unit 122 substitutes 1 for the variable CANDIDATE_GROUP_ID (F2104). The variable CANDIDATE_GROUP_ID is a variable corresponding to the group ID 951 in the group information table 145. Next, the grouping processing unit 122 determines whether the number of entries in the group information table 145 is 2 or more and 1 or less (step S2108). When the number is 2 or more (F2108: Yes), that is, when the number of groups is plural, the process proceeds to F2112. When the number is 1 or less (F2108: No), the process proceeds to F2152. In the case of (C) in FIG. 11, the number of entries in the group information table 145 is “2” (entries 601 and 602), and thus the process proceeds to F2112.

  In the case of F2108: Yes, the grouping processing unit 122 substitutes the first value of the belonging transfer device list 853 in the variable NOTICE_NE_ID in the i-th entry of the PoP information table 146 (F2112). Here, “NE” is an abbreviation of Network Entity and represents the transfer device 200. The variable NOTICE_NE_ID indicates the transfer device 200 that is one end point of the path in the transfer device network 10.

  When the PoP 500 group distribution process (F2100) is executed when i = 3, the top value of the belonging transfer device list 853 in the entry 875 when i = 3 is “201”. The grouping processing unit 122 substitutes “201” for the variable NOTICE_NE_ID. When the PoP group distribution process (F2100) is executed when i = 4, the top value of the belonging transfer device list 853 in the entry 877 when i = 4 is “203”. The grouping processing unit 122 substitutes “203” into the variable NOTICE_NE_ID.

  Next, the grouping processing unit 122 substitutes 1 for the loop counter j (F2116), and substitutes “65535” for the variable MIN_COST (F2120). The loop counter j is a variable that identifies an entry in the group information table 145 to be processed. The variable MIN_COST is a variable for searching for the minimum cost value. In F2116, a value larger than the cost value that can be set is substituted into the variable MIN_COST as an initial value. Here, the maximum value 65535 is substituted as the initial value of the variable MIN_COST before the comparison.

  Next, the grouping processing unit 122 determines whether or not the loop counter j is equal to or less than the number of entries in the group information table 145 (F2124). In the example of FIG. 11C, the number of entries in the group information table 145 is “2”. When the loop counter j is equal to or less than the number of entries in the group information table 145 (F2124: Yes), the process proceeds to F2128. On the other hand, if the loop counter j is not less than or equal to the number of entries in the group information table 145 (F2124: No), the process proceeds to F2152 because there is no entry to be processed.

  In the case of F2124: Yes, the grouping processing unit 122 searches the PoP information table 146 for an entry having the first PoP_ID in the belonging PoP list 952 of the jth entry in the group information table 145. For example, in the example of FIG. 11C, the entry when j = 1 is the entry 601. Therefore, the top PoP_ID “504” of the belonging PoP list 952 in the entry 601 is specified. The grouping processing unit 122 searches the PoP information table 146, and identifies the entry 878 whose PoP_ID 851 is “504” from the PoP information table 146.

  Then, the grouping processing unit 122 substitutes the identification information of the transfer device 200 at the head of the belonging transfer device list 853 of the searched entry into the variable CANDIDATE_NE_ID (F2128). The variable CANDIDATE_NE_ID indicates the transfer device 200 that is the other end point of the path in the transfer device network 10. When the searched entry is the entry 878, the identification information of the transfer device 200 at the head of the belonging transfer device list 853 is “204”. The grouping processing unit 122 substitutes “204” for the variable CANDIDATE_NE_ID.

  Next, the grouping processing unit 122 refers to the path management table 149 illustrated in FIG. 15 and identifies an entry including the variable NOTICE_NE_ID and the variable CANDIDATE_NE_ID in the path endpoint transfer device list 752. When the variable NOTICE_NE_ID is “201” and the variable CANDIDATE_NE_ID is “204”, the grouping processing unit 122 identifies the entry 777 whose path ID 751 is “603”.

  Then, the grouping processing unit 122 substitutes the inter-path cost 755 of the identified entry for the variable TEMP_COST (F2132). When the identified entry is the entry 777, the grouping processing unit 122 substitutes the value “400” of the inter-path cost 755 of the identified entry 777 for the variable TEMP_COST.

  Next, the grouping processing unit 122 determines whether or not the variable MIN_COST is larger than the variable TEMP_COST (F2136). When the variable MIN_COST is larger than the variable TEMP_COST (F2136: Yes), the process proceeds to F2140. When the variable MIN_COST is not larger than the variable TEMP_COST (F2136: No), the process proceeds to F2148. In the case of the entry 777 specified in F2132, since “65535” of the variable MIN_COST is larger than the value “400” of the inter-path cost 755, the process proceeds to F2140.

  In the case of F2136: Yes, the process proceeds to F2140, and the grouping processing unit 122 substitutes the value of the group ID 951 of the jth entry in the group information table 145 for CANDIDATE_GROUP_ID (F2140). When j = 1, in FIG. 11C, the group ID “1” of the entry 601 whose group ID 951 is “1” is substituted into the variable CANDIDATE_GROUP_ID.

  Next, the grouping processing unit 122 substitutes the variable TEMP_COST for the variable MIN_COST (F2144). When j = 1, the grouping processing unit 122 assigns “400” of the variable TEMP_COST to “65535” of the variable MIN_COST, and the variable MIN_COST becomes “400”. After F2144 or in the case of F2136: No, the grouping processing unit 122 increments the loop counter j by 1 (F2148) and returns to F2124. When j = 2, “502” is specified as the first PoP_ID of the belonging PoP list 952 in the group information table 145 shown in FIG. The grouping processing unit 122 searches the PoP information table 146 for an entry 876 whose PoP_ID 851 is “502”.

  Since the searched entry is the entry 876, the identification information of the transfer device 200 at the head of the belonging transfer device list 853 is “202”. The grouping processing unit 122 assigns “202” to the variable CANDIDATE_NE_ID. The variable NOTICE_NE_ID is “201”, and the variable CANDIDATE_NE_ID is “202”. Therefore, the grouping processing unit 122 identifies the entry 775 whose path ID 751 is “601” from the path management table 149.

  Then, the grouping processing unit 122 substitutes the value “200” of the inter-path cost 755 of the identified entry 775 for the variable TEMP_COST. Next, since “400” of the variable MIN_COST is larger than “200” of the variable TEMP_COST, the grouping processing unit 122 proceeds to F2140. The grouping processing unit 122 substitutes the value “2” of the group ID 951 of the j = 2nd entry of the group information table 145 for the variable CANDIDATE_GROUP_ID. Further, the grouping processing unit 122 assigns “200” of the variable TEMP_COST to “400” of the variable MIN_COST, and the variable MIN_COST becomes “200”.

  In this embodiment, the affiliation of the PoP 500 specified by the PoP_ID 851 of the entry of the PoP information table 146 is determined to be a group specified by the variable CANDIDATE_GROUP_ID so that the variable MIN_COST is minimized. Although it is preferable to determine the position to which the PoP 500 belongs so that the variable MIN_COST is minimized, the variable MIN_COST is not limited to the minimum value. For example, the variable MIN_COST does not have to be the minimum value as long as the value is lower than the initial value “65535”. For example, the obtained variable MIN_COST may be a value lower than the maximum value, or may be a value lower than a predetermined threshold value.

  Thereafter, the grouping processing unit 122 increments the loop counter j by 1 to set j = 3, and returns to F2124. When j = 3, F2124: No, and F2152 is executed. In the case of F2108: 1 or less or F2124: No, the grouping processing unit 122 adds the i-th item in the PoP information table 146 to the end of the belonging PoP list 952 of the entry whose group ID 951 value is the variable CANDIDATE_GROUP_ID in the group information table 145. The value of PoP_ID 851 of the entry is added (F2152).

  In the above example, the latest variable CANDIDATE_GROUP_ID is the value “2” of the group ID 951 of j = 2nd entry in the group information table 145. Therefore, the grouping processing unit 122 indicates an argument of the PoP group distribution process (F2100) at the end of the belonging PoP list 952 of the entry whose group ID 951 is “2” in the group information table 145. Loop counter i = PoP_ID 851 value “501” of the third entry 875 is added. As a result, the group information table 145 shown in FIG. 11 changes from (C) to (D).

  Next, in the i-th entry of the PoP information table 146, the grouping processing unit 122 substitutes the value of the current affiliation group 855 for the old affiliation group 854, and substitutes the variable CANDIDATE_GROUP_ID for the current affiliation group 855 (F2156). In the above example, in the i = third entry 875 of the PoP information table 146 shown in FIG. 12A, the grouping processing unit 122 sets the value “1” of the current group 855 to the old group 854. Overwrite and overwrite the current group 855 with the value “2” of the variable CANDIDATE_GROUP_ID at this time. As a result, the i = third entry 875 of the PoP information table 146 shown in FIG. 12A becomes as shown in FIG.

  Up to this point, the PoP group distribution process (F2100) when the i = third entry 875 is used as an argument has been described. However, the PoP group distribution process (F2100) when the i = 4th entry 877 is used as an argument. ) Is similarly processed. In this case, in F2112, the grouping processing unit 122 substitutes the first value “203” in the belonging transfer device list 853 in the entry 877 for the variable NOTICE_NE_ID.

  When j = 1 (F2116), in F2128, the grouping processing unit 122 identifies the entry 878 whose PoP_ID 851 value is the first value “504” of the belonging PoP list 952 in the j = 1st entry 601; The first value “204” of the belonging transfer device list 853 in the identified entry 878 is substituted into the variable CANDIDATE_NE_ID.

  When j = 1, in F2132, the grouping processing unit 122 identifies the entry 782 including the variable NOTICE_NE_ID = “203” and the variable CANDIDATE_NE_ID = “204” in the path endpoint transfer device list 752 of the path management table 15. The value “300” of the inter-path cost 755 of the entry 782 is substituted into TEMP_COST.

  When j = 1, because TEMP_COST “300” is smaller than MIN_COST “65535” (F2136: Yes), in F2140, the grouping processing unit 122 sets the value “1” of the group ID 951 of j = 1st entry 601. Is substituted into the variable CANDIDATE_GROUP_ID. When j = 1, in F2144, the grouping processing unit 122 sets TEMP_COST “300” to MIN_COST. Then, j = 2 (F2148).

  When j = 2, in F2128, the grouping processing unit 122 identifies the entry 876 whose PoP_ID 851 value is the first value “502” of the belonging PoP list 952 in the j = 2st entry 602, and identifies the identified entry The leading value “202” of the belonging transfer device list 853 in 876 is substituted into the variable CANDIDATE_NE_ID. When j = 2, in F2132, the grouping processing unit 122 identifies the entry 779 including the variable NOTICE_NE_ID = “203” and the variable CANDIDATE_NE_ID = “202” in the path endpoint transfer device list 752 of the path management table 15. The value “300” of the inter-path cost 755 of the entry 779 is substituted into TEMP_COST.

  Since TEMP_COST “300” is the same as MIN_COST “300” (F2136: No), F2140 and F2114 are not executed, and j = 3 (F2148). Thereafter, since j = 3, the grouping processing unit 122 performs F2124: No and executes F2152. At this time, the latest variable CANDIDATE_GROUP_ID is the value “1” of the group ID 951 of the j = 1st entry 601.

  Therefore, the grouping processing unit 122 indicates an argument of the group distribution processing (F2100) of the PoP 500 at the end of the belonging PoP list 952 of the entry whose group ID 951 is “1” in the group information table 145. The value “503” of the PoP_ID 851 of the loop counter i = fourth entry 877 is added. As a result, the group information table 145 shown in FIG. 11 changes from (D) to (E).

  Next, in the i = 4th entry 877 of the PoP information table 146 shown in FIG. 12A, the grouping processing unit 122 adds the current group 855 to the old group 854. The value “1” is overwritten, and the current group 855 is overwritten with the value “1” of the variable CANDIDATE_GROUP_ID at this time. As a result, the i = fourth entry 877 of the PoP information table 146 shown in FIG. 12A becomes as shown in FIG. That is, in the configuration example of FIG. 1, in the grouping process (F2000), the PoP information table 146 shown in FIG. 12B is completed.

  By the grouping process (F2000), the group information table 145 shown in FIG. 11E is generated, and the PoP 500 can be divided into two groups 1 and 2 as shown in FIG.

(Route information operation processing by grouping change)
Next, route information manipulation processing (F2200) by grouping change will be described. Since the PoP 500 has been grouped by the grouping process (F2000), it is necessary to manipulate the route information according to the group after grouping. The route information operation process by the grouping change is a process executed by the virtual router function unit 121 with the completion of the grouping process (F2000) as a trigger. In the route information operation processing by grouping change, difference route information is generated by taking the difference between the former group and the current group, the difference route information is advertised to the adjacent router 300, and the difference route information is set in the transfer device 200. It is processing to do. Note that the PoP information table 146 at this time is in the state shown in FIG.

  FIG. 18 is a flowchart illustrating a detailed processing procedure example of the route information operation processing (F2200) by the grouping change executed by the virtual router function unit 121. The virtual router function unit 121 rewrites the contents of the group-by-group old route information table 1050 with the information in the group-by-group current route information table 1000, and deletes all entries in the group-by-group current route information table 1000 (F2204). This state is shown in FIG. 9A.

  Next, the virtual router function unit 121 performs route information table change processing by grouping change (F2250), optimum route selection processing (F2300), difference route information table update processing (F2500), transfer device setting processing (F2600), route The information advertisement process (F2700) is executed.

  Then, the virtual router function unit 121 assigns the value of the current group 855 to the old group 854 for all entries in the PoP information table 146 shown in FIG. 12B (F2212). The PoP information table 146 after the processing of F2212 is (C) of FIG. Thereby, the route information operation process (F2200) by the grouping change in FIG. 18 is completed.

  Here, the route information table change process (F2250) by grouping change is a process for changing the route information table 141 shown in FIG. 7 according to the grouping of the grouping process (F2000) shown in FIG. . More specifically, for example, in the route information table 141 shown in FIG. 7A, the PoP priority 1104 and the information source group 1106 that were undefined before the grouping process (F2000) are set. . Details of the route information table change processing (F2250) by grouping change will be described with reference to FIG.

  The optimum route selection process (F2300) is a process for creating the group-by-group current route information table 1000 shown in FIG. 9B. Details of the optimum route selection process (F2300) will be described with reference to FIG. Also, the differential path information table update process (F2500) is a process for creating the differential path information table 142 shown in FIG. 8A. Details of the difference path information table update processing (F2500) will be described with reference to FIG.

  The transfer device setting process (F2600) is a process for setting the transfer device 200 so that packets can be transferred according to the group-specific current route information table 1000 created by the optimum route selection process (F2300). Specifically, the transfer device setting process (F2600) is a process of creating the input transfer table 225 and the output transfer table 245 and setting them in the transfer device 200. Details of the transfer device setting process (F2600) will be described with reference to FIG.

  The route information advertisement process (F2700) is a process for advertising the difference route information to the adjacent router 300. However, at this stage, since the transfer device 200 and the adjacent router 300 are in a state where communication is not possible (connection state 808 in FIG. 10A), entries 1225 to 1234 in the differential path information table 142 shown in FIG. 8A. Is not advertised. Details of the route information advertisement processing (F2700) will be described with reference to FIG. After the route information manipulation processing (F2200) by the grouping change shown in FIG. 18, the transfer device 200 and the adjacent router 300 become communicable by ARP resolution (connection state 808 in FIG. 10B). .

(Route information table change processing by grouping change)
FIG. 19 is a flowchart illustrating a detailed processing procedure example of the route information table changing process (F2250) by the grouping change shown in FIG. The virtual router function unit 121 refers to the top entry of the path information table 141 (F2254). The referenced entry is referred to as a “reference entry”. At this stage, it is assumed that the initial value “−1” is set in the PoP priority 1104 and the information source group 1106, respectively.

  Next, the virtual router function unit 121 determines whether or not a reference entry exists (F2258). If it exists (F2258: Yes), the virtual router function unit 121 identifies the PoP_ID stored in the information source PoP 1105 of the reference entry, and adds an entry having a value of PoP_ID 851 that matches the identified PoP_ID to the PoP information table 146. Identify from. For example, when the reference entry of the route information table 141 shown in FIG. 7A is the entry 1151, the PoP_ID stored in the information source PoP 1105 is “501”. Therefore, the virtual router function unit 121 identifies the entry 875 having the value of PoP_ID 851 that matches the identified PoP_ID “501” from the PoP information table 146 illustrated in FIG.

  Then, the virtual router function unit 121 substitutes the value of the PoP priority 852 and the value of the current group 855 of the identified entry into the PoP priority 1104 and the information source group 1106 of the reference entry of the path information table 141 (F2262). ). For example, the virtual router function unit 121 references the value “0” of the PoP priority 852 and the value “2” of the current group 855 of the identified entry 875 with reference to the path information table 141 shown in FIG. Substitute the PoP priority 1104 and the information source group 1106 of the entry 1151. As a result, the reference entry 1151 changes from (A) to (B) in FIG.

  Next, the virtual router function unit 121 refers to the next entry in the path information table 141 (F2266) and returns to F2258. In F2258, when the reference entry does not exist (F2258: No), the route information table change process (F2250) by the grouping change ends. Thus, if the route information table 141 is in the state of FIG. 7A, it is updated to FIG. 7B, and if the route information table 141 is in the state of FIG. Updated to (C).

(Optimum route selection process)
FIG. 20 is a flowchart showing a detailed processing procedure example of the optimum route selection processing (F2300) shown in FIG. The virtual router function unit 121 executes an optimum route selection process (F2300) using all entries in the route information table 141 created by the route information table change process (F2250) due to grouping change as arguments. That is, the optimum route selection process (F2300) is a process for selecting the optimum route from the route information table 141 due to the grouping change.

  The virtual router function unit 121 assigns “1” to the target group number N (F2302). The target group number N is a variable that identifies a group to be processed in the optimum route selection process (F2300). Next, the virtual router function unit 121 tries to refer to the head entry of the path information table 141 (F2304). The referenced entry is referred to as a “reference entry”.

  Next, the virtual router function unit 121 determines whether or not a reference entry exists (F2308). When the reference entry does not exist (F2308: No), the virtual router function unit 121 increments the target group number N by 1 (F2309). Then, the virtual router function unit 121 determines whether or not the target group number N is equal to or smaller than the number of entries in the group information table 145 shown in FIG. 11E (F2310). If the target group number N is not less than or equal to the number of entries in the group information table 145 shown in FIG. 11E (F2310: No), there is no unprocessed group, and the optimum route selection process (F2300) ends. . on the other hand. When the target group number N is equal to or less than the number of entries in the group information table 145 shown in FIG. 11E (F2310: Yes), the target group number N is not processed, and the process returns to F2304.

  In F2308, when the reference entry exists (F2308: Yes), the virtual router function unit 121 assigns the value of the destination network 1101 of the optimum route information candidate to the variable CANDIDATE_NW with the reference entry as the optimum route information candidate (F2312). . For example, when the reference entry is the entry 1151 of the route information table 141 shown in FIG. 7B, the entry 1151 is set as the optimum route information candidate, and the value “F” of the destination network 1101 is set as the virtual router function unit. 121 is substituted into the variable CANDIDATE_NW.

  Next, the virtual router function unit 121 determines whether or not IP reachability to the variable CANDIDATE_NW is possible (F2316). Since BGP does not select route information without IP reachability as the optimum route, F2316 is executed each time the variable CANDIDATE_NW is updated.

  The route information advertised by BGP is assigned a NEXT_HOP attribute which is one of BGP path attributes. It is possible to reach the advertised route by sending a packet to the device having the IP address indicated in the NEXT_HOP attribute, but it is possible to reach the IP address indicated in the NEXT_HOP attribute. It is necessary to determine whether or not there is. For this reason, whether or not IP can be reached in the variable CANDIDATE_NW is determined in F2316. In this embodiment, it is assumed that the IP address of the advertisement source router 1102 in the route information table 141 is indicated in the NEXT_HOP attribute. The destination network 1101 handled in this embodiment is assumed to have IP reachability from the virtual router function unit 121.

  When the IP reachability to the variable CANDIDATE_NW is impossible (F2316: No), the virtual router function unit 121 tries to refer to the next entry in the path information table 141 (F2328), and executes F2308. When the IP reachability to the variable CANDIDATE_NW is possible (F2316: Yes), the virtual router function unit 121 selects the destination among the entries whose target group number N is the value of the usage group 1001 in the group current path information table 1000. The network 1002 determines whether there is an entry having the variable CANDIDATE_NW (F2320).

  Since the entry in the group-by-group current route information table 1000 has been deleted in F2204 in FIG. 18, when the reference entry is the first entry in the route information table 141, F2320 is No and the process proceeds to F2324. Then, the virtual router function unit 121 adds an entry for the optimum route information candidate in which a field having the usage group 1001 as the target group number N is added to the group-specific current route information table 1000. That is, the target group number N is assigned to the use group 1001 of the entry, and the optimum route information candidate is assigned to the destination network 1002 to the route acquisition source 1008 (F2324). Then, the virtual router function unit 121 tries to refer to the next entry in the path information table 141 (F2328) and executes F2308.

  For example, when the entries 1151 to 1155 of the route information table 141 shown in FIG. 7B are referred to (optimum route information candidates), F2320 is No for any optimum route information candidate in F2320. F2324 is executed. Therefore, in the case of the route information table 141 shown in FIG. 7B, F2332 and F2400 are not executed, the optimum route selection process (F2300) is completed, and the group-by-group current route information table 1000 contains entries in F2324. By addition, it is updated as shown in FIGS. 9A to 9B.

  Further, since the entry of the group-by-group current route information table 1000 is added by F2324, among the entries in the group-by-group current route information table 1000 whose usage group 1001 has the target group number N, the destination network 1002 has the variable CANDIDATE_NW There is a case where there is an entry that is (F2320: Yes). In this case, the virtual router function unit 121 sets an entry of the current route information table by group 1000 in which the destination network 1002 is the variable CANDIDATE_NW as current optimum route information (F2332), and executes route information comparison processing (F2400).

  The route information comparison process (F2400) is a process for determining whether the optimum route information candidate or the current optimum route information is the optimum route. Therefore, the optimum route selection process (F2300) selects the optimum route information candidate as the optimum route when the current optimum route information does not exist. When the current optimum route information exists, the optimum route information candidate and the current optimum route are selected. This is a process of selecting one of the information as the optimum route.

(Route information comparison process)
FIG. 21 is a flowchart illustrating a detailed processing procedure example of the route information comparison processing (F2400) illustrated in FIG. The virtual router function unit 121 executes the route information comparison process (F2400) using the target group number N, the optimum route information candidate, and the current optimum route information as arguments 1 to 3.

  First, the virtual router function unit 121 determines which of the group belonging to the optimum route information candidate (argument 2) and the group belonging to the current optimum route information (argument 3) equal to the target group number N (argument 3). Processing for selecting an argument (group identity determination processing) is executed (F2404, F2408, F2412). That is, a route equal to the target group number N is preferentially selected. The group to which the optimum route information candidate belongs is the value of the information source group 1106 in the route information table 141. The group to which the current optimum route information belongs is the value of the information source group 1007 in the group-specific current route information table 1000.

  Specifically, the virtual router function unit 121 determines whether the group to which the optimum route information candidate belongs and the group to which the current optimum route information belongs are the same group (F2404). When it is the same group (F2420: Yes), the process proceeds to F2424. That is, in the case of the same group (F2420: Yes), since the argument 1 and the argument 2 are the same as the target group number N (argument 3), the superiority of the argument 1 and the argument 2 cannot be determined. Therefore, the process proceeds to F2424.

  If they are not the same group (F2404: No), the virtual router function unit 121 determines whether or not the value of the information source group 1007 of the current optimum route information and the target group number N are the same (F2408). If they are the same (F2408: Yes), the optimum route in the group with the target group number N is the current optimum route information. Therefore, the virtual router function unit 121 determines the current optimum route information as the optimum route in the group of the target group number N (F2420). Thereby, the virtual router function unit 121 ends the route information comparison process (F2400).

  If they are not the same group (F2408: No), the virtual router function unit 121 determines whether or not the value of the information source group 1106 of the optimum route information candidate and the target group number N are the same (F2412). If they are the same (F2412: Yes), the virtual router function unit 121 adds the current optimum route information to the group-by-group current route information table 1000, and the optimum route information candidate in which a field having the use group 1001 as the target group number N is added. Rewrite to That is, the target group number N is assigned to the use group 1001 of the entry of the current optimum route information, and the optimum route information candidate is assigned to the destination network 1002 to the route acquisition source 1008 (F2416). The entry generated in this way indicates the optimum route. Thereby, the virtual router function unit 121 ends the route information comparison process (F2400).

  When they are not the same group (F2412: No), the process proceeds to F2424. That is, since the argument 1 and the argument 2 are not the same as the target group number N (argument 3), the superiority of the argument 1 and the argument 2 cannot be determined. Therefore, the process proceeds to F2424.

  Then, the virtual router function unit 121 compares the PoP priority 1104 of the optimum route information candidate with the PoP priority 1005 of the current optimum route information (F2424). When the PoP priority 1005 of the current optimum route information is higher than the PoP priority 1104 of the optimum route information candidate (F2424: high), the process proceeds to F2420. When the PoP priority 1005 of the current optimum route information is lower than the PoP priority 1104 of the optimum route information candidate (F2424: low), the process proceeds to F2416.

  When the PoP priority 1104 of the optimal route information candidate and the PoP priority 1005 of the current optimal route information are the same (F2424: same), the virtual router function unit 121 sets the other path attribute 1103 of the optimal route information candidate, The other path attribute 1004 of the optimum route information is compared, and either the optimum route information candidate or the current optimum route information is determined as the optimum route (F2428). For example, the virtual router function unit 121 determines the one having the higher importance (or priority) specified by the other path attribute as the optimum route.

  Then, when the optimum route information candidate is determined as the optimum route (F2432: No), the virtual router function unit 121 proceeds to F2416. On the other hand, when the current optimum route information is determined as the optimum route (F2432: Yes), the process proceeds to F2420, and the virtual router function unit 121 ends the route information comparison process (F2400). The optimum route is determined by the route information comparison process (F2400).

  In FIG. 21, the comparison (F2424) of the PoP priority 1005 may be executed without executing the group identity determination processing (F2404, F2408, F2412).

(Differential route information table update process)
FIG. 22 is a flowchart illustrating a detailed processing procedure example of the difference path information table update processing (F2500) illustrated in FIG. First, the virtual router function unit 121 performs initialization by deleting all entries in the differential path information table 142 (F2504). Next, the virtual router function unit 121 tries to refer to the head entry of the PoP information table 146 shown in FIG. 12B (F2508). Referenced entries are referred to as reference entries. The virtual router function unit 121 determines whether there is a reference entry (F2512).

  When there is a reference entry in the PoP information table 146 shown in FIG. 12B (F2512: Yes), the virtual router function unit 121 stores the old membership group 854 and the current membership of the reference entry in the differential path information table 142. It is determined whether or not there is an entry having the values of the old information source group 1206 and the current information source group 1207 that are the same as the value of the group 855 (step S2516). When it exists (F2516: Yes), it transfers to F2520. If it does not exist (F2516: No), the virtual router function unit 121 executes a difference acquisition process (F2550) and proceeds to F2520.

  In F2520, the virtual router function unit 121 refers to the next entry in the PoP information table 146 (F2520) and returns to F2512. If there is no reference entry in the PoP information table 146 (F2512: No), there is no unprocessed entry, so the virtual router function unit 121 ends the differential path information table update process (F2500).

(Difference acquisition process)
FIG. 23 is a flowchart illustrating a detailed processing procedure example of the difference acquisition processing (F2550) illustrated in FIG. The group-specific current route information table 1000 has been updated from FIG. 9A to FIG. 9B by the optimum route selection process (F2300). The virtual router function unit 121 uses the value of the old group 854 of the reference entry of the PoP information table 146 shown in FIG. 12B as the argument 1 and the reference entry of the PoP information table 146 shown in FIG. The difference acquisition process (F2550) is executed with the value of the current member group 855 as the argument 2.

  The virtual router function unit 121 acquires an entry in which the argument 2 is recorded in the usage group 1001 in the group-specific current route information table 1000 illustrated in FIG. 9B (F2552). The acquired entry is referred to as a current route information list. For example, when the reference entry of the PoP information table 146 shown in FIG. 12B is the entry 878, the current group 855 is “1”. Therefore, the virtual router function unit 121 acquires the entries 1025 to 1029 whose usage group 1001 is “1” from the group current path information table 1000 illustrated in FIG. 9B. The acquired entries 1025 to 1029 are held as a current route information list.

  Next, the virtual router function unit 121 attempts to refer to the head entry of the group-by-group old path information table 1050 shown in FIG. 9B (F2554). The referred entry is referred to as a reference entry. When the reference entry exists (F2556: Yes), the process proceeds to F2560. When the reference entry does not exist (F2556: No), the process proceeds to F2558. In the case of the group-by-group old route information table 1050 shown in FIG. 9B, the entry is empty, so there is no reference entry (F2556: No), and the process proceeds to F2558.

  In the case of F2556: No, the virtual router function unit 121 adds an entry to the difference path information table 142 (F2558), and ends the difference acquisition process (F2550). The entry added to the differential path information table 142 includes a part of the remaining fields in the current path information list, an argument 1 for the old information source group 1206, an argument 2 for the current information source group 1207, and deletion / update. This is an entry in which “update” is set in 1209.

  For example, when the reference entry in F2512 of FIG. 22 is the entry 878 of the PoP information table 146 shown in FIG. 12B, the argument 1 is the value “1” of the old group 854, and the argument 2 is the current The value of the group 855 is “1”. Therefore, entries 1225 to 1229 are added to the differential path information table 142 (see FIG. 8A).

  When the next entry 876 of the entry 878 is referred to in F2512 of FIG. 22, the argument 1 is the value “1” of the old group 854, and the argument 2 is the value “2” of the current group 855 (see FIG. 12 (B)). Accordingly, entries 1230 to 1234 are added to the differential path information table 142 (see FIG. 8A).

  In the case of F2556: Yes, the virtual router function unit 121 determines whether or not the value of the use group 1051 of the reference entry in the group-by-group old path information table 1050 is the same as the argument 1 (F2560). If they are not identical (F2560: No), the virtual router function unit 121 attempts to refer to the next entry in the group-by-group old route information table 1050 (step S2572), and determines whether or not the reference entry exists. (F2556).

  On the other hand, if they are the same (F2560: Yes), the virtual router function unit 121 tries to refer to the first entry in the current route information list (F2562). The referred entry is referred to as a reference entry. The virtual router function unit 121 determines whether there is a reference entry in the current route information list (F2564). If it exists (F2564: Yes), the virtual router function unit 121 determines whether the reference entry in the group-specific old route information table 1050 and the reference entry in the current route information list have the same destination network 1002, 1052. Judgment is made (F2566).

  If they are not identical (F2566: No), the virtual router function unit 121 attempts to refer to the next entry in the current route information list (F2582), and returns to F2564. On the other hand, if they are the same (F2566: Yes), the virtual router function unit 121 determines whether there is a difference between both reference entries (F2568). Specifically, for example, the virtual router function unit 121 has different values in any one item of the advertisement source routers 1003 and 1053, the other path attributes 1004 and 1054, and the route acquisition sources 1008 and 1058 between the reference entries. Determine whether or not.

  When there is no difference (F2568: No), the process proceeds to F2570. On the other hand, if there is a difference (F2568: Yes), the virtual router function unit 121 adds an entry to the difference route information table 142 (F2574) and deletes the reference entry of the current route information list from the current route information list. (F2570), it returns to F2572. The entry added to the differential route information table 142 is a reference entry in the current route information list, and further includes an argument 1 in the old information source group 1206, an argument 2 in the current information source group 1207, and an “update” in the delete / update 1209. It is a set entry.

  On the other hand, in F2564, when there is no reference entry in the current route information list (F2564: No), the virtual router function unit 121 adds an entry to the difference route information table 142 (F2578) and returns to F2572. The entry added to the differential path information table 142 is a reference entry in the group-by-group old path information table 1050, an argument 1 for the old information source group 1206, an argument 2 for the current information source group 1207, and “ The entry is set to “delete”.

  In the difference acquisition process (F2550) in the route information operation process (F2200) by the grouping change shown in FIG. 18, F2558 is executed, and F2574 and F2578 are not executed. Thereby, the differential path information table 142 shown in FIG. 8A is created. Note that F2578 in the difference acquisition process (F2550) is a process for adding a field in which deletion / update 1209 is “updated” in F2558, whereas a field in which deletion / update 1209 is “deleted” is added. It is processing.

(Transfer device setting process)
FIG. 24 is a flowchart illustrating a detailed processing procedure example of the transfer device setting process (F2600) illustrated in FIG. The transfer device setting process (F2600) is a process of creating the input transfer table 225 shown in FIG. 3 and the output transfer table 245 shown in FIG.

  The virtual router function unit 121 tries to refer to the head entry of the adjacent router management table 144 shown in FIG. 10A (F2604). The referred entry is referred to as a reference entry. The virtual router function unit 121 determines whether there is a reference entry (F2608). If it exists (F2608: Yes), the virtual router function unit 121 attempts to refer to the top entry of the differential path information table 142 shown in FIG. 8A (F2612). The referred entry is referred to as a reference entry.

  The virtual router function unit 121 determines whether or not there is a reference entry in the differential path information table 142 illustrated in FIG. 8A (F2616). If it exists (F2616: Yes), the virtual router function unit 121 determines the value of the connection transfer device 804 in the reference entry of the adjacent router management table 144 shown in FIG. 10A and the differential path information shown in FIG. 8A. The value of the route acquisition source 1208 in the reference entry of the table 142 is compared (F2620). Then, the virtual router function unit 121 determines whether or not both values are the same value (F2624).

  For example, when the reference entry of the adjacent router management table 144 shown in FIG. 10A is the entry 825, the value of the connection transfer device 804 is “201 (2/1)”. When the reference entry of the differential route information table 142 illustrated in FIG. 8A is the entry 1225, the value of the route acquisition source 1208 is “201 (2/1)”. In this case, since the value of the connection transfer device 804 and the value of the route acquisition source 1208 are both “201 (2/1)”, they are determined to be the same value.

  When the values are the same (F2624: Yes), the virtual router function unit 121 attempts to refer to the next entry in the differential path information table 142 illustrated in FIG. 8A (F2640), and proceeds to F2616. That is, the reference entry of the differential path information table 142 having the same value is not set.

  On the other hand, when the values are not the same (F2624: No), the virtual router function unit 121 executes the transfer device setting target determination process (F3100), tries to refer to the next entry in the differential path information table 142 (F2640), and returns to F2616. Transition. The transfer device setting target determination process (F3100) is a process of determining whether or not the reference entry in the differential path information table 142 is an entry to be set to the transfer device 200. Details of the transfer device setting target determination process (F3100) will be described later with reference to FIG.

  Further, in F2616, when there is no reference entry in the differential path information table 142 shown in FIG. 8A (F2616: No), the virtual router function unit 121 sets the neighbor router management table 144 shown in FIG. Attempt to refer to the next entry (F2644), and return to F2608. In F2608, when there is no reference entry in the adjacent router management table 144 shown in FIG. 10A (F2608: No), the virtual router function unit 121 ends the transfer device setting process (F2600).

  When a packet destined for the destination network 1002 of the entries 1025 to 1034 in the group-specific current route information table 1000 shown in FIG. 9B is input to the transfer device network 10 by the transfer device setting process (F2600), the packet is routed. The data is output from the acquisition source 1208 and delivered to the destination network 1002.

(Transfer device setting target determination process)
FIG. 25 is a flowchart illustrating a detailed processing procedure example of the transfer device setting target determination processing (F3100). The virtual router function unit 121 searches the PoP information table 146 shown in FIG. 12B for an entry having the value of the connection PoP_ID 807 in the reference entry of the adjacent router management table 144 shown in FIG. . The virtual router function unit 121 acquires the value of the old group 854 and the value of the current group 855 in the searched entry (F3104).

  Next, the virtual router function unit 121 determines whether or not the reference entry of the differential path information table 142 illustrated in FIG. 8A is a setting target for the transfer apparatus 200 (F3108). Specifically, for example, the virtual router function unit 121 determines that the old information source group 1206 value and the current information source group 1207 value in the reference entry of the differential path information table 142 illustrated in FIG. It is determined whether or not the value of the affiliation group 854 matches the value of the current affiliation group 855. If they match, the reference entry in the differential path information table 142 shown in FIG. 8A becomes a setting target for the transfer apparatus 200.

  Next, when the reference entry in the differential path information table 142 is not the setting target for the transfer device 200 (F3112: No), the virtual router function unit 121 determines the transfer device setting target determination process (F3100). Is ended, and the process proceeds to process F2640 in FIG.

  On the other hand, when it is a setting target (F3112: Yes), the virtual router function unit 121 includes the value of the connection transfer device 804 and the value of the route acquisition source 1208 compared in F2620 of FIG. 24 in the path endpoint transfer device list 752. The entry is specified from the path management table 149 shown in FIG. 15 (F3116). As a result, the path passing through the transfer device 200 specified by the value of the connection transfer device 804 and the value of the route acquisition source 1208 is specified. The virtual router function unit 121 executes an input / output transfer table creation process (F3000). The input / output transfer table creation process (F3000) is a process for creating the input transfer table 225 and the output transfer table 245 to be sent to the transfer apparatus 200. Details of the input / output transfer table creation processing (F3000) will be described with reference to FIG.

  After the input / output transfer table creation processing (F3000), the virtual router function unit 121 sets the created entry of the input transfer table 225 and the entry of the output transfer table 245 in the transfer device 200 (F3124). Specifically, for example, the virtual router function unit 121 sends the entry of the input transfer table 225 and the output transfer table to the transfer device 200 in accordance with the reference entry deletion / update 1209 of the differential path information table 142 shown in FIG. 8A. A request to delete or update 245 entries is made.

  For example, when the value of the deletion / update 1209 of the reference entry in the differential path information table 142 is “deletion”, the virtual router function unit 121 performs the entry and output transfer of the corresponding input transfer table 225 from the target transfer device 200. An entry in the table 245 is deleted. In the case of “update”, the virtual router function unit 121 transmits the entry of the corresponding input transfer table 225 and the entry of the output transfer table 245 to the target transfer apparatus 200 for update.

  For example, in the case of “update”, the virtual router function unit 121 transmits the created entry of the input forwarding table 225 to the forwarding device 200 identified by the connection forwarding device 804 in the reference entry of the adjacent router management table 144, Set in the transfer device 200. Further, the virtual router function unit 121 transmits the created entry of the output transfer table 245 to the transfer apparatus 200 specified by the route acquisition source 1208 in the reference entry of the differential route information table 142 illustrated in FIG. Set in the transfer device 200.

  In the case of “delete”, the virtual router function unit 121 deletes the created entry of the input transfer table 225 from the transfer device 200 specified by the connection transfer device 804 in the reference entry of the adjacent router management table 144. Further, the virtual router function unit 121 deletes the created entry of the output transfer table 245 from the transfer apparatus 200 specified by the path acquisition source 1208 in the reference entry of the differential path information table 142. Thereby, the virtual router function unit 121 ends the transfer device setting target determination process (F3100).

(I / O transfer table creation process)
FIG. 26 is a flowchart showing a detailed processing procedure example of the input / output transfer table creation processing (F3000) shown in FIG. The virtual router function unit 121 executes the input / output transfer table creation process (F3000) with the reference entry in F2612 as argument 1, the reference entry in F2604 as argument 2, and the entry specified in F3116 as argument 3.

  First, the virtual router function unit 121 determines whether or not the first value (the value on the left side) of the path endpoint transfer device list 752 of the argument 3 matches the value of the route acquisition source 1208 of the argument 1. (F3004). If they match (F3004: Yes), the virtual router function unit 121 assigns the first value (left value) of the transfer label value list 756 of argument 3 to the variable OUT_LABEL, and substitutes the second value (right side). Is substituted into the variable IN_LABEL (F3008). Then, the process proceeds to F3016. The variable OUT_LABEL is a variable corresponding to the output transfer label. The variable IN_LABEL is a variable corresponding to the input transfer label.

  If they do not match (F3004: No), the virtual router function unit 121 assigns the first value (left value) of the transfer label value list 756 of argument 3 to the variable IN_LABEL, and the second value (right side) Is substituted into the variable OUT_LABEL (F3012). Then, the process proceeds to F3016.

  Next, the virtual router function unit 121 creates an entry in the input transfer table 225 (F3016). Specifically, for example, the virtual router function unit 121 sets the port number of the connection transfer device 804 whose port number 1301 is the argument 2, the value of the destination network 1201 whose argument network 1302 is the argument 1, and the identification label 1303. An entry is created in which the value is the value of the path ID 751 of the argument 3 and the value of the transfer label 1304 is the variable IN_LABEL.

  Next, the virtual router function unit 121 reads an entry in the connection transfer device 804 that has the same value as the value of the route acquisition source 1208 of argument 1 from the adjacent router management table 144 shown in FIG. Search for. Then, the virtual router function unit 121 substitutes the value of the adjacent router MAC 802 of the searched entry into the variable DEST_MAC, and substitutes the value of the connection port MAC 805 into the variable SOURCE_MAC (F3020). The variable DEST_MAC is a variable corresponding to the destination MAC address, and the variable SOURCE_MAC is a variable corresponding to the source MAC address.

  Next, the virtual router function unit 121 creates an entry in the output transfer table 245 (F3024). Specifically, for example, the virtual router function unit 121 sets the port number 1401 as the port number of the route acquisition source 1208 with the argument 1, the destination network 1402 as the value of the destination network 1201 with the argument 1, and the identification label 1403. An entry is created in which the value is the value of path ID 751 of argument 3, the value of transfer label 1404 is variable OUT_LABEL, the value of rewrite destination MAC 1405 is variable DEST_MAC, and the rewrite source MAC is variable SOURCE_MAC. As a result, an entry in the input transfer table 225 and an entry in the output transfer table 245 are created.

(Route information advertisement processing)
FIG. 27 is a flowchart illustrating a detailed processing procedure example of the route information advertisement processing (F2700) illustrated in FIG. The route information advertisement process (F2700) is a process for advertising the route information (reference entry of the difference route information table 142) to the adjacent router 300.

  The virtual router function unit 121 tries to refer to the head entry of the adjacent router management table 144 (F2704). Referenced entries are referred to as reference entries. If the reference entry does not exist (F2708: No), the virtual router function unit 121 ends the route advertisement process (F2700).

  On the other hand, when the reference entry exists (F2708: Yes), the virtual router function unit 121 determines whether the connection state 808 of the reference entry is “communication enabled” or “communication disabled” (F2712). When it is “communication impossible” (F2712: No), the virtual router function unit 121 tries to refer to the next entry in the adjacent router management table 144 (F2716), and returns to F2708.

  In the route information advertisement process (F2700) in the route information operation process (F2200) by the grouping change shown in FIG. 18, the adjacent router management table 144 has the contents shown in FIG. That is, since the values of the connection states 808 of the entries 825 to 829 are all “communication impossible”, the reference entry of the differential path information table 142 illustrated in FIG. 8A is not transmitted to any router 300. On the other hand, when “communication is possible” (F2712: Yes), the virtual router function unit 121 tries to refer to the head entry of the differential path information table 142 (F2720). Referenced entries are referred to as reference entries.

  The virtual router function unit 121 determines whether there is a reference entry in the differential path information table 142 (F2724). When it does not exist (F2724: No), the process proceeds to F2716. On the other hand, if it exists (F2724: Yes), the virtual router function unit 121 searches the PoP information table 146 for an entry in which the value of the connection PoP_ID 807 in the reference entry of the adjacent router management table 144 is set to PoP_ID 851. Then, the virtual router function unit 121 acquires the value of the old group 854 and the value of the current group 855 in the searched entry (F2728).

  Next, the virtual router function unit 121 determines whether or not the reference entry in the differential path information table 142 is an advertisement target to the adjacent router 300 (F2732). Specifically, for example, the virtual router function unit 121 determines that the value of the old information source group 1206 and the value of the current information source group 1207 in the reference entry of the differential path information table 142 are the values of the old member group 854 acquired in F2728. Then, it is determined whether or not it matches the value of the current group 855. If they match, the reference entry in the differential path information table 142 becomes the advertisement target to the adjacent router 300.

  When the reference entry of the difference path information table 142 is not the advertising target for the adjacent router 300 (F2737: No), the process proceeds to F2744. On the other hand, when the reference entry of the differential route information table 142 is an object to be advertised to the adjacent router 300 (F2736: Yes), the virtual router function unit 121 advertises the reference entry of the differential route information table 142 (F2740). Specifically, for example, the virtual router function unit 121 deletes / updates the reference entry of the differential route information table 142 for the adjacent router 300 specified by the adjacent router ID 801 in the reference entry of the adjacent router management table 144. Advertise according to the value of 1209.

  That is, when the value of the deletion / update 1209 is “deletion”, the virtual router function unit 121 transmits the reference entry of the differential path information table 142 to the adjacent router 300 as deletion information. The adjacent router 300 deletes the reference entry of the received differential route information table 142 from its own route table (not shown). On the other hand, when the value of the delete / update 1209 is “update”, the virtual router function unit 121 transmits the reference entry of the differential route information table 142 to the adjacent router as route information. The adjacent router 300 overwrites the reference entry of the received differential route information table 142 in its route table (not shown).

  Thereafter, the virtual router function unit 121 attempts to refer to the next entry in the difference path information table 142 (F2744), and returns to F2724. As described above, in the route information advertisement process (F2700), the route information (reference entry of the difference route information table 142) can be distributed to the adjacent router 300 in a communicable state.

<Packet transfer after grouping>
Next, packet transfer after the group information table 145 shown in FIG. 11E is created by the grouping process (F2000) and the route information operation process (F2200) by grouping change will be described.

  When the packet is input to the transfer apparatus network 10, the packet is transferred according to the group-by-group current path information table 1000 shown in FIG. 9B. Here, a packet transfer when a packet addressed to the destination network G is input to the transfer apparatus network 10 from the port (2/1) of the transfer apparatus 201 will be described as an example.

  The transfer apparatus 201 belongs to PoP501. Referring to the group information table 145 shown in FIG. 11E, PoP 501 belongs to transfer group 2 with group ID = 2, and therefore transfer apparatus 201 also belongs to transfer group 2. In the group-by-group current route information table 1000 shown in FIG. 9B, an entry in which the value of the use group 1001 is group ID = 2 of the transfer group 2 and the value of the destination network 1002 is the destination network address G of the packet is This is entry 1031.

  The input transfer table 225 of the transfer apparatus 201 shown in FIG. 3A and the output transfer table 245 of the transfer apparatus 202 shown in FIG. 5A are the preset label transfer table of FIG. This is set based on the information recorded in the entry 1031 of the group-specific current route information table 1000 shown in FIG. 9B.

  The following describes that the packet addressed to G is transferred to the port (2/1) of the transfer apparatus 202 that is the route acquisition source 1008 of the entry 1031 of the group-based current route information table 1000 shown in FIG. 9B.

  An IP packet in which no MPLS label is inserted is input to the port (2/1) of the transfer apparatus 201. Since the MPLS label is not inserted into the packet input from the physical port 250, the input packet processing unit 220 of the transfer device 201 refers to the input transfer table 225 shown in FIG. In the input forwarding table 225, there is an entry 1325 that has (2/1) that is the port to which the packet is input in the port number 1301 and that has the destination network G that is the destination IP address of the input packet in the destination network 1302. To do.

  The input packet processing unit 220 of the transfer apparatus 201 inserts an MPLS header having an identification label value “601” that is the identification label 1303 of the entry 1325 between the MAC header and the IP header of the input packet. The input packet processing unit 220 of the transfer apparatus 201 inserts an MPLS header having a transfer label value “4001”, which is the transfer label 1304 of the entry 1325, between the MPLS header and the MAC header that are already inserted in the input packet. To do.

  In addition, the input packet processing unit 220 of the transfer device 201 inserts an input port information header in which (2/1) that is the port number at which the packet is input to the transfer device 201 is recorded in the packet. The input packet processing unit 220 of the transfer apparatus 201 passes the packet in which two MPLS labels are inserted to the label transfer processing unit 230.

  The label transfer processing unit 230 of the transfer device 201 is a port number in which the value of the input port 1351 is recorded in the input port information header from the label transfer table 235 of the transfer device 201 shown in FIG. 2/1), and the entry 1361 in which the value of the input transfer label 1352 is the transfer label value “4001” of the packet is searched.

  The label transfer processing unit 230 of the transfer apparatus 201 rewrites the transfer label value “4001” of the packet with the value “4002” of the output transfer label 1353 of the entry 1361. The label transfer processing unit 230 of the transfer apparatus 201 inserts an output port information header in which the value (1/1) of the output port 1354 of the entry 1361 is recorded into the packet, and passes it to the output packet processing unit 240.

  The destination network address of the input packet is “G”, the identification label value inserted in the packet is “601”, and the transfer label value inserted in the packet is “4002”. No entry satisfying this condition exists in the output transfer table 245 of the transfer apparatus 201.

  The output packet processing unit 240 of the transfer apparatus 201 refers to (1/1) of the port number recorded in the output port information header included in the packet, removes the output port information header, and then refers to the port number (1 / 1) packet is output. The output packet is input to the physical port 250 having the port number (1/1) of the transfer device 206.

  Since the packet with the MPLS label inserted is input, the input packet processing unit 220 of the transfer device 206 records the input port information header in which (1/1) is the port number at which the packet is input to the transfer device 206. Is inserted into the packet, and the packet is passed to the label transfer processing unit 230.

  The label transfer processing unit 230 of the transfer device 206 is the port number in which the value of the input port 1351 is recorded in the input port information header from the label transfer table 235 of the transfer device 206 shown in FIG. 1/1) and the value of the input transfer label 1352 is searched for the transfer label value “4002” of the packet.

  The label transfer processing unit 230 of the transfer device 206 rewrites the transfer label value “4002” of the packet with the output label value “4003” recorded in the output transfer label 1353 of the entry 1366. The label transfer processing unit 230 of the transfer device 206 inserts the output port information header in which (1/2) recorded in the output port 1354 of the entry 1366 is recorded into the packet, and passes it to the output packet processing unit 240.

  Since the transfer device 206 is not connected to the adjacent router 300, there is no entry in the output transfer table 245. For this reason, the output packet processing unit 240 of the transfer device 206 refers to the port number (1/2) recorded in the output port information header, removes the output port information header, and then refers to the port number (1/2). ) To output the packet. The output packet is input to the physical port 250 having the port number (1/1) of the transfer device 202.

  Since the packet with the MPLS label inserted is input, the input packet processing unit 220 of the transfer apparatus 202 uses the input port information header that records (1/1) which is the port number at which the packet is input to the transfer apparatus 202. The packet is inserted into the packet and passed to the label transfer processing unit 230.

  The label transfer processing unit 230 of the transfer device 202 is the port number in which the value of the input port 1351 is recorded in the input port information header from the label transfer table 235 of the transfer device 202 shown in FIG. 1/1) and the entry 1381 whose input transfer label 1352 value is the packet transfer label value “4003” is searched.

  The label transfer processing unit 230 of the transfer device 202 rewrites the transfer label value “4003” of the packet with the output label value “4004” recorded in the output transfer label 1353 of the entry 1381. The label transfer processing unit 230 of the transfer device 202 inserts the output port information header recorded (2/1) recorded in the output port 1354 of the entry 1381 into the packet, and passes it to the output packet processing unit 240.

  The destination network address of the input packet is “G”, the identification label value inserted in the packet is “601”, and the transfer label value inserted in the packet is “4004”. The output packet processing unit 240 of the transfer apparatus 202 searches the output transfer table 245 for an entry that satisfies this condition.

  In this case, the entry 1425 of the output transfer table 245 of the transfer device 202 shown in FIG. Accordingly, the output packet processing unit 240 of the transfer device 202 rewrites the destination MAC address of the packet received from the label transfer processing unit 230 to the broadcast address “BROADCAST” recorded in the rewrite destination MAC 1405 of the entry 1425. In addition, the output packet processing unit 240 of the transfer device 202 rewrites the transmission MAC address of the packet to “MAC202” recorded in the rewrite source MAC 1406 and inserts the identification label value “601” and the transfer label value “ 4004 ".

  The output packet processing unit 240 of the transfer apparatus 202 refers to the port number (2/1) recorded in the output port information header, and has the referenced port number (2/1) after removing the output port information header. A packet is output from the physical port 250. The output packet is output from the port number (2/1) of the transfer device 202.

  As described above, when a packet addressed to the destination network G is input from the port (2/1) of the transfer apparatus 201, the route acquisition source 1008 of the entry 1031 is obtained according to the group-specific current route information table 1000 illustrated in FIG. 9B. A packet is output from the port (2/1) of the transfer device 202.

  Similarly to the transfer example of the packet addressed to the destination network G, the packet input to the transfer device network 10 through the transfer devices 201 to 205 is transferred to the destination network 1002 according to the group-specific current route information table 1000 shown in FIG. 9B. Is transferred to the network recorded in

  Next, the adjacent routers 301 to 305 are connected to the connection transfer device 804 corresponding to the adjacent router ID 801 in the adjacent router management table 144. The virtual router function unit 121 performs ARP resolution for the adjacent router IP 803 in the entries 825 to 829 in the adjacent router management table 144 shown in FIG. 10A, and records the obtained MAC addresses in the adjacent router MAC 802, respectively. Then, the connection state 808 is set to “communication enabled”.

  As a result, the virtual router function unit 121 processes the BGP Open message with the routers 301 to 305, and the eBGP adjacency relationship is established between the virtual router function unit 121 and the routers 301 to 305. When the eBGP adjacency relationship is established, the virtual router function unit 121 rewrites the connection status 808 of the entries 825 to 829 in the adjacent router management table 144 to “communication enabled”. With the above processing, the adjacent router management table 144 is updated from (A) to (B) in FIG.

<(2) Route advertisement processing by router connection>
Next, route advertisement processing (F2900) by router connection will be described. The route advertisement processing by router connection is processing in which the virtual router function unit 121 advertises route information to the routers 301 to 305 having the BGP adjacency relationship.

  FIG. 28 is a flowchart showing a detailed processing procedure example of route advertisement processing (F2900) by router connection. First, the virtual router function unit 121 executes the differential path information table update process (F2500) illustrated in FIG. In the difference route information table update process (F2500) in the route advertisement process (F2900) by the router connection, the PoP information table 146 in (C) of FIG. 12 updated in the route information operation process (F2200) by the grouping change in FIG. Is used. Therefore, in FIG. 28, the virtual router function unit 121 creates the differential path information table 142 shown in FIG. 8B.

  Next, the virtual router function unit 121 executes the route information advertisement process (F2700) shown in FIG. The virtual router function unit 121 tries to refer to the head entry of the adjacent router management table 144 shown in FIG. 10B (F2704). The head entry 825 of the adjacent router management table 144 shown in FIG. 10B exists (F2708: Yes), and the connection state 808 of the reference entry 825 is “communication enabled” (F2712: Yes). Therefore, the virtual router function unit 121 tries to refer to the head entry of the differential path information table 142 shown in FIG. 8B (F2720).

  Since the first entry 1225 of the differential path information table 142 shown in FIG. 8B exists (F2724: Yes), the virtual router function unit 121 sets the reference entry 825 of the adjacent router management table 144 shown in FIG. An entry having the value “501” of the connection PoP_ID 807 is searched from the PoP information table 146 shown in FIG. An entry 875 is retrieved. The virtual router function unit 121 acquires the value “2” of the old group 854 and “2” of the current group 855 of the entry 875 (F2728).

  The combination of the value “1” of the old information source group 1206 and the value “1” of the current information source group 1207 of the reference entry 1225 of the difference path information table 142 shown in FIG. 8B is the value of the old member group 854 acquired in F2728. It does not match the combination of “2” and the value “2” of the current group 855. Therefore, the entry 1225 is not an advertising target (F2732, F2736: No). Thereafter, the virtual router function unit 121 refers to the next entry 1226 of the differential path information table 142 illustrated in FIG. 8B (F2744), and returns to F2724. The entries 1226 to 1229 are the same as the entry 1225.

  When the reference entry of the differential path information table 142 shown in FIG. 8B is the entry 1230, the combination of the value “2” of the old information source group 1206 and the value “2” of the current information source group 1207 of the reference entry 1230 is It matches the combination of the value “2” of the former group 854 and the value “2” of the current group 855 acquired in F2728.

  Therefore, the entry 1230 becomes an advertising target (F2732, 2736: Yes). The deletion / update 1209 of the entry 1230 to be advertised is “update”. Therefore, the virtual router function unit 121 uses the entry 1230 as route information for the router 301 identified by the value “301” of the adjacent router ID 801 of the reference entry 825 of the adjacent router management table 144 shown in FIG. Advertising (F2740).

  Next, the virtual router function unit 121 attempts to refer to the next entry 1231 of the differential path information table 142 illustrated in FIG. 8B (F2744). The entries 1231 to 1234 are advertised in the same manner as the entry 1230. The deletion / update 1209 of the entries 1231 to 1234 is “update”. Therefore, the virtual router function unit 121 routes the entries 1231 to 1234 to the router 301 specified by the value “301” of the adjacent router ID 801 of the reference entry 825 of the adjacent router management table 144 shown in FIG. Advertising as information (F2740).

  Thereafter, the virtual router function unit 121 tries to refer to the next entry of the entry 1234 in the differential path information table 142 shown in FIG. 8B (F2744), but the next entry of the entry 1234 in the differential path information table 142 shown in FIG. 8B. Does not exist (F2724: No). Therefore, the virtual router function unit 121 tries to refer to the next entry 826 of the entry 825 of the adjacent router management table 144 shown in FIG. 10B (F2716). There is an entry 826 to be referred to (F2708: Yes). The virtual router function unit 121 executes the processing F2708 to F2744 for the entries 826 to 829 in the adjacent router management table 144 shown in FIG.

  In the case of the entry 826, the connection PoP_ID 807 is “502”. The virtual router function unit 121 sets the entry having the value “502” of the connection PoP_ID 807 of the reference entry 826 of the adjacent router management table 144 shown in FIG. 10B to the PoP information table shown in FIG. Search from 146. Entry 876 is retrieved. The virtual router function unit 121 acquires the value “2” of the old group 854 and “2” of the current group 855 of the entry 875 (F2728).

  In the case of the entry 826, as with the entry 875, the entries 1230 to 1234 of the differential path information table 142 illustrated in FIG. Therefore, the virtual router function unit 121 routes the entries 1230 to 1234 to the router 302 specified by the value “302” of the adjacent router ID 801 of the reference entry 826 of the adjacent router management table 144 shown in FIG. Advertising as information (F2740).

  In the case of the entry 827, the connection PoP_ID 807 is “503”. The virtual router function unit 121 sets the entry having the value “503” of the connection PoP_ID 807 of the reference entry 827 of the adjacent router management table 144 shown in FIG. 10B to the PoP information table shown in FIG. Search from 146. An entry 877 is retrieved. The virtual router function unit 121 acquires the value “1” of the old group 854 and “1” of the current group 855 of the entry 877 (F2728).

  The combination of the value “1” of the old information source group 1206 and the value “1” of the current information source group 1207 of the reference entry 1225 of the difference path information table 142 shown in FIG. 8B is the value of the old member group 854 acquired in F2728. It matches the combination of “1” and the value “1” of the current group 855.

  Therefore, the entry 1225 becomes an advertising target (F2732, 2736: Yes). The deletion / update 1209 of the entry 1230 to be advertised is “update”. Therefore, the virtual router function unit 121 uses the entry 1225 as route information for the router 303 identified by the value “303” of the adjacent router ID 801 of the reference entry 827 of the adjacent router management table 144 shown in FIG. Advertising (F2740).

  Next, the virtual router function unit 121 attempts to refer to the next entry 1226 of the differential path information table 142 illustrated in FIG. 8B (F2744). The entries 1226 to 1229 are also advertised in the same manner as the entry 1225. The deletion / update 1209 of the entries 1226 to 1229 is “update”. Therefore, the virtual router function unit 121 routes the entries 1226 to 1229 to the router 303 specified by the value “303” of the adjacent router ID 801 of the reference entry 827 of the adjacent router management table 144 shown in FIG. Advertising as information (F2740). The entries 1230 to 1234 are not advertised because they are not advertised.

  In the case of the entry 828, the connection PoP_ID 807 is “504”. The virtual router function unit 121 sets the entry having the value “504” of the connection PoP_ID 807 of the reference entry 828 of the adjacent router management table 144 shown in FIG. 10B to the PoP information table shown in FIG. Search from 146. An entry 878 is retrieved. The virtual router function unit 121 acquires the value “1” of the old group 854 and the current group 855 “1” of the entry 878 (F2728).

  In the case of the entry 828, as with the entry 877, the entries 1225 to 1229 in the differential path information table 142 shown in FIG. Therefore, the virtual router function unit 121 routes the entries 1225 to 1229 to the router 304 specified by the value “304” of the adjacent router ID 801 of the reference entry 828 of the adjacent router management table 144 shown in FIG. Advertising as information (F2740).

  In the case of the entry 829, the connection PoP_ID 807 is “504”. The virtual router function unit 121 sets the entry having the value “504” of the connection PoP_ID 807 of the reference entry 828 of the adjacent router management table 144 shown in FIG. 10B to the PoP information table shown in FIG. Search from 146. An entry 878 is retrieved. The virtual router function unit 121 acquires the value “1” of the old group 854 and the current group 855 “1” of the entry 878 (F2728).

  In the case of the entry 829, as with the entry 877, the entries 1225 to 1229 in the differential path information table 142 shown in FIG. Therefore, the virtual router function unit 121 routes the entries 1225 to 1229 to the router 305 identified by the value “305” of the adjacent router ID 801 of the reference entry 829 of the adjacent router management table 144 shown in FIG. Advertising as information (F2740). When the next entry of the entry 829 in the adjacent router management table does not exist (F2708: No), the virtual router function unit 121 ends the route information advertisement process (F2700) of FIG.

  Next, the virtual router function unit 121 assigns the values of the current group 855 to the old group 854 for all entries 875 to 878 of the PoP information table 146 shown in FIG. 12C (F2904). In FIG. 12C, since the values of the old affiliation group 854 and the current affiliation group 855 of all entries 875 to 876 in the PoP information table 146 are the same, the PoP information table 146 shown in FIG. 12C is not changed. . Thereby, the virtual router function unit 121 ends the route advertisement processing (F2900) by router connection.

<(3) New route acquisition process>
Next, the new route acquisition process (F2800) will be described. Since the adjacency relationship between the routers 301 to 305 and the eBGP is established, the route information (adjacent routers 301 to 305 and the destination network 600) for the network addresses A to E of the adjacent routers 301 to 305 is stored in the virtual router function unit 121. Advertised. Then, the virtual router function unit 121 executes a new route acquisition process (F2800) shown in FIG. The route information table 141 has the contents shown in FIG.

  FIG. 29 is a flowchart illustrating a detailed processing procedure example of the new route acquisition processing (F2800). First, the virtual router function unit 121 adds the PoP priority 1104, the information source to the route information advertised from the adjacent routers 301 to 305 (the adjacent routers 301 to 305, the destination network 600, and the path attribute included in the route information). The PoP 1105, the information source group 1106, and the route acquisition source 1107 are added and added as entries 1156 to 1164 to the route information table 141 shown in FIG. 7B (F2804). That is, the information of the adjacent router 300 of the advertised route information is stored in the advertisement source router 1102, the destination network 600 is stored in the destination network 1101, and the path attribute included in the advertised route information is the other path attribute 1103. To store. In addition, fields of PoP priority 1104, information source PoP 1105, information source group 1106, and route acquisition source 1107 are added and stored. As a result, the route information table 141 has the contents shown in FIG.

  Next, the virtual router function unit 121 copies the contents of the entries 1025 to 1034 in the group-by-group current route information table 1000 shown in FIG. 9B to the group-by-group old route information table 1050, and then the group-by-group current route information table. The 1000 entries 1025 to 1034 are deleted (F2808). That is, the contents of the old route information table for each group are replaced with the current route information table for each group, and then the current route information table for each group is deleted (F2808). As a result, as shown in FIG. 9C, entries 1075 to 1084 of the group-by-group old route information table 1050 are created. Next, the virtual router function unit 121 executes the optimum route selection process shown in FIG. 20 using all the entries 1151 to 1164 in the route information table 141 shown in FIG. 7C as arguments (F2300).

  When the optimum route selection process (F2300) in the grouping process (F2000) is executed, the optimum of this flow is the same as when the entries 1151-1155 of the route information table 141 shown in FIG. In the route selection processing (F2300), the virtual router function unit 121 executes processing F2308: Yes on the entries 1151-1158 of the route information table 141 shown in (C) of FIG. 7 and F2312-1328 of FIG. .

  As a result, the entries 1151 to 1158 in which the value “1” of the usage group 1001 is added to the entries 1151 to 1158 of the route information table 141 shown in FIG. 7C become the current route information for each group shown in FIG. 9C. They are added as entries 1025 to 1032 of the table 1000.

  Next, the virtual router function unit 121 tries to refer to the next entry of the entry 1158 in the path information table 141 shown in FIG. 7C (F2328). Since the next entry 1159 exists (F2308: Yes), the virtual router function unit 121 sets the reference entry 1159 in the route information table 141 as the optimum route information candidate 1159, and the destination network A in the destination network 1101 of the optimum route information candidate 1159. Is substituted into the variable CANDIDATE_NW (F2312).

  Since there is IP reachability to the destination network A (F2316: Yes), the value of the destination network 1002 is CANDIDATE_NW among the entries 1025 to 1032 in which the usage group 1001 is “1” in the entry of the current route information table by group 1000. An entry having a certain destination network A exists (F2320: Yes). This entry is an entry in which the value “1” of the usage group 1001 is added to the entry 1156 having the destination network A. For convenience, the current optimum route information 1156 is set (F2332).

  Next, the virtual router function unit 121 executes the route attribute comparison process (F2400) illustrated in FIG. 21 with the target group number N = 1, the optimum route information candidate 1159, and the current optimum route information 1156 as arguments.

  The value of the information source group 1106 (refer to the information source group 1007 is actually referred to) of the current optimum route information 1156 is “2”, and the value of the information source group 1106 of the optimum route information candidate 1159 is “1”. Are not identical (F2404: No). Further, the target group number N = 1 and the value “2” of the information source group 1106 of the current optimum route information 1156 are not the same (F2408: No).

  On the other hand, since the value “1” of the information source group 1106 of the optimal route information candidate 1159 is the same as the target group number N = 1 (F2412: Yes), the current optimal route information 1156 is stored in the group-specific current route information table 1000. Then, it is rewritten to the optimum route information candidate 1159 added with a field in which the value of the use group 1001 is “1”, and is set as the entry 1030 of the group-by-group current route information table 1000 (F2416). Accordingly, the virtual router function unit 121 ends the route attribute comparison process (F2400) illustrated in FIG.

  Next, the virtual router function unit 121 tries to refer to the next entry of the entry 1159 in the path information table 141 shown in FIG. 7C (F2328). The next entry 1160 exists (F2308: Yes). Similarly to the entry 1159, the entry 1160 also executes the processes F2304 to F2332, F2400 to F2408, and F2420, so that the current optimum route information 1157 is rewritten to the entry 1031 in the group-by-group current route information table 1000 of FIG. (F2416).

  Next, the virtual router function unit 121 tries to refer to the next entry of the entry 1160 in the path information table 141 shown in FIG. 7C (F2328). The next entry 1161 exists (F2308: Yes). Similarly to the entry 1160, the entry 1161 is rewritten with the entry 1032 in the current optimum route information 1158 in the group-by-group current route information table 1000 by executing the processes F2304 to F2332, F2400 to F2408, and F2420. (F2416).

  Next, the virtual router function unit 121 tries to refer to the next entry of the entry 1161 in the path information table 141 shown in FIG. 7C (F2328). The next entry 1162 exists (F2308: Yes). Also for the entry 1162, by executing the processes F2308 and F2312-2328 as in the case of the entry 1151, the entry 1162 to which the field for which the use group is 1 is added becomes the entry 1033 of the current routing information table by group 1000. Added.

  Next, the virtual router function unit 121 tries to refer to the next entry of the entry 1162 in the path information table 141 (F2328). The next entry 1163 exists (F2308: Yes). The virtual router function unit 121 sets the reference entry 1163 of the route information table 141 shown in FIG. 7C as the optimum route information candidate 1163, and sets the destination network D that is the value of the destination network 1101 of the optimum route information candidate 1163 as a variable. Substituting for CANDIDATE_NW (F2312).

  Since there is IP reachability to the destination network D (F2316: Yes), the value of the destination network 1002 is CANDIDATE_NW among the entries 1025 to 1034 where the usage group 1001 is “1” in the entry of the current route information table 1000 by group. An entry 1033 exists as an entry having a certain destination network D (F2320: Yes). This entry 1033 is set as the current optimum route information 1033 (F2332).

  Next, the virtual router function unit 121 executes the route attribute comparison process (F2400) of FIG. 21 using the target group number N = 1, the optimum route information candidate 1163, and the current optimum route information 1033 as arguments.

  Since the value of the information source group 1007 of the current optimum route information 1033 is “1” and the value of the information source group 1106 of the optimum route information candidate 1163 is “2”, they are not the same (F2404: No). On the other hand, since the group number N = 1 and the value “1” of the information source group 1007 of the current optimum route information 1033 are the same (F2408: Yes), the optimum route in the group 1 is changed while keeping the current optimum route information 1033. There is no (F2420). Thereby, the virtual router function unit 121 ends the route attribute comparison process (F2400) of FIG.

  Next, the virtual router function unit 121 tries to refer to the next entry of the entry 1163 in the path information table 141 (F2328). The next entry 1164 exists (F2308: Yes). Similarly to the entry 1151, the entry 1164 is executed as the entry 1034 of the group-specific current route information table 1000 by executing the processes F2308 and F2312-2328 in the same manner as in the case of the entry 1151 and adding the field with the use group as 1. Added.

  Next, the virtual router function unit 121 tries to refer to the next entry of the entry 1164 in the path information table 141 (F2328). Since there is no entry next to the entry 1164 in the path information table 141 (F2308: No), the virtual router function unit 121 increments the target group number N from 1 to 2 (F2309). The group number N is 2 and the number of entries in the group information table 145 is 2 or less (F2310: Yes). The path information table 141 in FIG. 7C is referred to as the path information table 141, and the virtual router function unit 121 tries to refer to the head entry (F2304).

  Similar to the processing performed for the entries 1151 to 1164 when the group number N is 1, the processing F2308 to 2332 and F2400 to 2432 are executed for the entries 1151 to 1164 when the group number N is 2. . As a result, entries 1035 to 1044 of the group-specific current route information table 1000 in FIG. 9C are created.

  Next, the virtual router function unit 121 tries to refer to the next entry of the entry 1164 in the path information table 141 (F2328). Since there is no entry next to the entry 1164 in the route information table 141 (F2308: No), the target group number N is incremented by 1 from 2 to 3 (F2309). Since the group number N is 3 and the number of entries in the group information table 145 is not less than 2 (F2310: No), the virtual router function unit 121 ends the optimum route selection process (F2300). The optimum route selection process (F2300) in FIG. 29 creates the group-by-group current route information table 1000 shown in FIG. 9C.

  Next, in FIG. 29, the virtual router function unit 121 executes the differential path information table update process shown in FIG. 22 (F2500). In the differential path information table update process (F2500), first, the virtual router function unit 121 performs initialization by deleting all entries in the differential path information table 142 (F2504). The virtual router function unit 121 tries to refer to the head entry of the PoP information table 146 shown in FIG. 12C (F2508).

  There is a head entry 878 of the PoP information table 146 shown in FIG. 12C (F2512: Yes). An existing entry 878 is set as a reference entry. The same combination of the value of the current information source group 1207 and the value of the old information source group 1206 as the combination of “1” which is the value of the current group 855 of the reference entry 878 and “1” which is the value of the old group 854 The entry having does not exist in the differential path information table 142 (F2516: No). Then, the virtual router function unit 121 sets “1” as the value of the current group 855 of the reference entry 878 as argument 1 and “1” as the value of the old group 854 of the reference entry 878 as argument 1 in FIG. The difference acquisition process (F2550) is executed.

  The virtual router function unit 121 adds entries 1025 to 1034 in which “1” that is the value of the current group 855 of the reference entry 878 is recorded in the usage group 1001 from the group-specific current route information table 1000 illustrated in FIG. 9C. Obtain (F2552). Entries 1025 to 1034 are held as a current route information list.

  Next, the virtual router function unit 121 tries to refer to the head entry of the group-based old path information table 1050 shown in FIG. 9C (F2554). In the group-based old route information table 1050 shown in FIG. 9C, there is an entry 1075 (hereinafter referred to as a reference entry) as the first entry (F2556: Yes), and “1”, which is the value of the usage group 1001 of the reference entry 1075, It is the same as “1” that is the value of the old group 854 of argument 2 (F2560: Yes).

  The virtual router function unit 121 attempts to refer to the head entry of the route information list (F2562), and the reference entry 1025 of the current route information list exists (F2564: Yes). The reference entry 1075 of the group-based old route information table 1050 shown in FIG. 9C and the reference entry 1025 of the current route information list have the network F that is the same destination network 1002 and 1052 (F2566: Yes). The advertisement source routers 1003 and 1053, the other path attributes 1004 and 1054, and the route acquisition sources 1008 and 1058 have the same value (F2568: No). Therefore, the virtual router function unit 121 deletes the reference entry 1025 from the current route information list. Thus, entries 1026 to 1034 remain in the current route information list (F2570).

  Next, the virtual router function unit 121 tries to refer to the next entry of the entry 1075 of the group-by-group old path information table 1050 shown in FIG. 9C (F2572), and the next entry 1076 of the entry 1075 of the group-by-group old path information table 1050. Exists (F2556: Yes). Similarly to the entry 1075, the entries 1076 to 1079 are deleted from the current route information list by executing the processing F2556 to 2572. As a result, entries 1030 to 1034 remain in the current route information list (F2570).

  Next, the virtual router function unit 121 attempts to refer to the next entry of the entry 1079 of the group-by-group old path information table 1050 illustrated in FIG. 9C (F2572). The next entry 1080 exists (F2556: Yes). The value of the usage group 1001 of the entry 1080 is “2”, which is different from “1” that is the value of the old group 854 of the argument 2 of the difference acquisition process (F2550) (F2560: No). Therefore, the virtual router function unit 121 attempts to refer to the next entry of the entry 1084 of the group-based old route information table 1050 illustrated in FIG. 9C (F2572). Similarly, for the entries 1081 to 1084, the value of the usage group 1001 of the entry 1080 is “2”, which is different from “1” which is the value of the old group 854 of the argument 2 of the difference acquisition process (F2550) (F2560: No). Therefore, the virtual router function unit 121 attempts to refer to the next entry of the entry 1084 of the group-by-group old route information table 1050 illustrated in FIG. 9C (F2572), but the next entry does not exist (F2556: No).

  As a result, the virtual router function unit 121 sets the value of the old information source group 1206 to the argument 1 (the current group 855 of the reference entry 878 in the partial fields of the entries 1030 to 1034 which are the remaining entries of the current route information list. A field in which the value of the current information source group 1207 is the argument 2 (the value of the old group 854 of the reference entry 878 is “1”) and the value of the delete / update 1209 is “update”. The added entries 1225 to 1229 are added to the difference path information table 142 (F2558).

  As described above, the virtual router function unit 121 sets “1” as the value of the current group 855 of the reference entry 855 and “1” as the value of the old group 854 of the reference entry 855 as the argument 1. 12 difference acquisition process (F2550) is complete | finished. By this process, entries 1225 to 1229 in the differential path information table 142 shown in FIG. 8C are created.

  Next, in FIG. 22, the virtual router function unit 121 tries to refer to the next entry of the entry 878 of the PoP information table shown in FIG. 12C (F2520). The next entry 876 of the entry 878 of the PoP information table 146 exists (F2512: Yes). The same combination of the value of the current information source group 1207 and the value of the old information source group 1206 as the combination of “2” that is the value of the current group 855 of the reference entry 876 and “2” that is the value of the old group 854 Does not exist in the differential path information table 142 (F2516: No).

  Therefore, the virtual router function unit 121 sets “1” as the value of the current group 855 of the reference entry 878 and “2” as the value of the old group 854 of the reference entry 878 as the argument 1 as shown in FIG. The difference acquisition process (F2550) is executed. As in the case of the entry 878, the virtual router function unit 121 executes the difference acquisition process (F2550), thereby creating the entries 1230 to 1234 of the difference path information table 142 illustrated in FIG. 8C.

  Next, in FIG. 22, the virtual router function unit 121 attempts to refer to the next entry of the entry 876 in the PoP information table shown in FIG. 12C (F2520). The next entry 875 of the entry 876 of the PoP information table 146 exists (F2512: Yes), and the combination of “2” which is the value of the current group 855 of the reference entry 875 and “2” which is the value of the old group 854 An entry having the same combination of the value of the current information source group 1207 and the value of the old information source group 1206 exists in the entry 1230 of the differential path information table 142 (F2516: Yes).

  Accordingly, the virtual router function unit 121 tries to refer to the next entry of the entry 875 of the PoP information table 146 shown in FIG. 12C without executing the difference acquisition process (F2550) (F2508). The next entry 877 of the entry 875 of the PoP information table 146 shown in (C) of FIG. 12 exists (F2512: Yes), and the value of the current belonging group 855 of the reference entry 877 is “1” and the old belonging group 854 An entry having the same combination of the value of the current information source group 1207 and the value of the old information source group 1206 as the combination of the value “1” exists in the entry 1225 of the differential path information table 142 (F2516: Yes). .

  Therefore, the virtual router function unit 121 tries to refer to the next entry of the entry 877 of the PoP information table shown in FIG. 12C without executing the difference acquisition process (F2550) (F2508). Since there is no entry next to the entry 877 in the PoP information table 146 (F2512: No), the virtual router function unit 121 ends the differential path information table update process (F2500) illustrated in FIG. Thereby, the differential path information table 142 shown in FIG. 8C is completed.

  Next, in FIG. 29, the virtual router function unit 121 executes the transfer device setting process (F2600) shown in FIG. In the transfer device setting process (F2600), the virtual router function unit 121 tries to refer to the head entry of the adjacent router management table 144 shown in FIG. 10B (F2604). Since the head entry 825 of the adjacent router management table 144 shown in FIG. 10B exists (F2608: Yes), the virtual router function unit 121 refers to the head entry of the differential path information table 142 shown in FIG. 8C. (F2612). There is a head entry 1225 in the difference path information table 142 (F2616: Yes).

  Next, the virtual router function unit 121 sets the value of the connection transfer device 804 in the reference entry 825 in the adjacent router management table 144 shown in FIG. 10B and the reference entry 1225 in the differential path information table 142 shown in FIG. 8C. The value of the route acquisition source 1208 is specified (F2620). The specified values are the port (2/1) of the transfer device 201 and the port (2/1) of the transfer device 204, and are different (F2624: No). Therefore, the virtual router function unit 121 executes the transfer device setting target determination process shown in FIG. 25 (F3100).

  In the transfer device setting target determination process (F3100) in FIG. 25, the virtual router function unit 121 uses the adjacent router management table 144 shown in FIG. 10B from the PoP information table 146 shown in FIG. The entry 875 having the value “501” of the connection PoP_ID 807 in the reference entry is searched. Then, the virtual router function unit 121 acquires the value “2” of the old group 854 and the value “2” of the current group 855 in the searched entry 875 (F3104).

  Next, the virtual router function unit 121 determines whether or not the reference entry 1225 of the differential path information table 142 illustrated in FIG. 8C is a setting target for the transfer apparatus 200 (F3108). Specifically, the value “1” of the old information source group 1206 and the value “1” of the current information source group 1207 in the reference entry 1225 are the same as the value “2” of the old member group 854 acquired in F3104 and the current member group 855. Does not match the value “2”. Therefore, the virtual router function unit 121 determines that the reference entry 1225 is not a setting target for the transfer apparatus 200 (F3108, F3112: No). As a result, the virtual router function unit 121 ends the transfer device setting target determination process (F3100) in FIG. 25, and proceeds to F2604 in FIG.

  Next, in FIG. 24, the virtual router function unit 121 attempts to refer to the next entry of the entry 1225 of the differential path information table 142 illustrated in FIG. 8C (F2640). As in the case of the entry 1225, the virtual router function unit 121 executes the processes F 2616 to 2640 and F 3100 to 3112, and determines that the next entries 1226 to 1229 are not the setting targets for the transfer apparatus 200. As a result, the virtual router function unit 121 ends the transfer device setting target determination process (F3100) in FIG. 25, and proceeds to F2604 in FIG.

  Next, in FIG. 24, the virtual router function unit 121 refers to the next entry of the entry 1229 of the differential path information table 142 illustrated in FIG. 8C (F2640). The next entry 1230 exists (F2616: Yes). For the entry 1230 as well as the entry 1226, the virtual router function unit 121 executes processes F2620, F2624, and F3100-3104. In process F2620, the value “201 (2/1)” of the connection transfer device 804 of the reference entry 825 of the adjacent router management table 144 shown in FIG. 10B and the difference path information table shown in FIG. The value “202 (2/1)” of the route acquisition source 1208 of the reference entry 1230 of 142 is compared. Since they are not the same value (F2624: No), the virtual router function unit 121 executes the transfer device setting target determination process of FIG. 25 (F3100).

  In the transfer device setting target determination process (F3100), the value “2” of the old information source group 1206 and the value “2” of the current information source group in the reference entry 1230 are the values “2” of the acquired old member group 854 and the current It matches the value “2” of the belonging group 855, respectively. Therefore, the virtual router function unit 121 determines that the entry 1230 is a setting target for the transfer apparatus 200 (F3108, F3112: Yes), and proceeds to F3116.

  Next, the virtual router function unit 121 determines the value “201 (2/1)” and the reference entry of the connection transfer device 804 of the reference entry 825 compared in F2620 of FIG. 24 from the path management table 149 shown in FIG. The entry 775 including the value “202 (2/1)” of the route acquisition source 1208 of 1230 in the path endpoint transfer device list 752 is specified (F3116).

  Next, the virtual router function unit 121 uses the entry 1230 of the differential path information table 142 acquired in F2612 as the argument 1, the entry 825 of the adjacent router management table 144 referred to in F2604 as the argument 2, and the entry in the path management table 149. With 775 as the argument 3, the input / output transfer table creation process (F3000) shown in FIG. 26 is executed.

  In the input / output transfer table creation processing (F3000), the first value (201 (2/1)) of the path endpoint transfer device list 752 of the entry 775 of the argument 3 and the route acquisition of the entry 1230 of the argument 1 are obtained. It does not match the value “202 (2/1)” of the original 1208 (F3004: No). Therefore, the virtual router function unit 121 assigns the first (left side) value “4001” of the transfer label value list 756 of the entry 775 of the argument 3 to IN_LABEL, and substitutes the second (right side) value “4004”. Substitute into the variable OUT_LABEL (F3012).

  Next, the virtual router function unit 121 creates an entry in the input transfer table 225 (F3016). In this case, the virtual router function unit 121 sets the port number (2/1) of the connection transfer device 804 of the entry 825 in which the value of the port number 1301 is the argument 2 and the destination of the entry 1230 in which the value of the destination network 1302 is the argument 1. The entry 1326 of the input transfer table 225 in which the value “A” of the network 1201, the value “601” of the path ID 751 of the entry 775 whose value of the identification label 1303 is the argument 3 and the value of the transfer label 1304 is the variable IN_LABEL “4001” create.

  Next, the virtual router function unit 121 deletes the entry 826 in the connection transfer apparatus 804 from the adjacent router management table 144 in which the same value as the value “202 (2/1)” of the route acquisition source 1208 of the argument 1 is set. Search for. Then, the value “MAC302” of the adjacent router MAC802 of the searched entry 826 is substituted for the variable DEST_MAC, and the value “MAC202” of the connection port MAC805 is substituted for the variable SOURCE_MAC (F3020).

  Next, the virtual router function unit 121 creates an entry in the output transfer table 245 (F3024). In this case, the virtual router function unit 121 sets the port number (2/1) of the route acquisition source 1208 having the port number 1401 as the argument 1 and the value “A” of the destination network 1201 having the value of the destination network 1402 as the argument 1; The value of the identification label 1403 is the path ID 751 value “601” of the argument 3, the value of the transfer label 1404 is the variable OUT_LABEL “4004”, the value of the rewrite destination MAC 1405 is the variable DEST_MAC “MAC302”, and the rewrite source MAC is the variable SOURCE_MAC “MAC202”. ”Is created. Thereby, the virtual router function unit 121 ends the input / output transfer table creation process (F3000) of FIG. And it transfers to F3124 of FIG.

  Next, in FIG. 25, the virtual router function unit 121 sets the created entry 1326 of the input transfer table 225 and entry 1426 of the output transfer table 245 in the transfer apparatus 200 (F3124). In this case, since the value of the deletion / update 1209 of the reference entry 1230 of the difference path information table 142 is “update”, the virtual router function unit 121 uses the entry 1326 of the input transfer table 225 created in process F3016 as the adjacent router. A setting request is sent to the transfer apparatus 201 identified by the value “201” of the connection transfer apparatus 804 in the reference entry 825 of the management table 144. That is, the entry 1326 is transmitted to the transfer device 201.

  Next, the device control unit 210 of the transfer device 201 that has received the entry 1326 updates the input transfer table 225 in the transfer device 201. As a result, the entry 1326 in FIG. 3B is set. In addition, since the value of the deletion / update 1209 of the reference entry 1230 in the difference path information table 142 is “update”, the virtual router function unit 121 uses the entry 1426 of the output transfer table 245 created in process F3024 as the difference path information. A setting request is sent to the transfer apparatus 202 identified by the value “202” of the route acquisition source 1208 of the reference entry 1230 of the table 142. That is, the entry 1426 is transmitted to the transfer device 202. That is, the entry 1426 is transmitted to the transfer device 202.

  Next, the device control unit 210 of the transfer device 202 that has received the entry 1426 updates the output transfer table 245 in the transfer device 202. As a result, the entry 1426 of FIG. 5B is set (F3124), and the process proceeds to F2640 of FIG. Next, the virtual router function unit 121 attempts to refer to the next entry of the entry 1230 of the differential path information table 142 illustrated in FIG. 8B (F2640). For the entries 1231 to 1234 subsequent to the entry 1230, the processes F2616 to 2644 and F3100 are executed in the same manner as the entry 1230. At this time, an entry 1327 of the input transfer table 225 of the transfer apparatus 201 shown in FIG. 3B is set by the process F3124 in the entry 1234, and the output of the transfer apparatus 203 shown in FIG. An entry 1440 of the forwarding table 245 is set (F3124).

  After the transfer device setting target determination process (F3100) is executed for the entry 1234, the virtual router function unit 121 tries to refer to the next entry of the entry 1234 in the differential path information table 142 (F2640). Since there is no next entry in the difference path information table 142 (F2616: No), the virtual router function unit 121 tries to refer to the next entry in the entry 825 in the adjacent router management table 144 (F2644).

  Since there is no entry next to the entry 829 in the adjacent router management table 144 (F2608: No), the virtual router function unit 121 ends the transfer device setting process (F2600) shown in FIG.

  When a packet destined for the destination network 1002 in the group-specific current route information table 1000 shown in FIG. 9C is input to the transfer device network 10 by the transfer device setting process (F2600), the packet is output from the route acquisition source 1208. And delivered to the destination network 1002.

  Next, in FIG. 29, the virtual router function unit 121 executes the route information advertisement process (F2700) of FIG. As described above, the virtual router function unit 121 performs the process F2704 with reference to the adjacent router management table 144 illustrated in FIG. 10B and the entries 1225 to 1234 in the differential path information table 142 illustrated in FIG. 8C. ~ F2744 is executed.

  As a result, the virtual router function unit 121 advertises the entries 1225 to 1229 of the differential route information table 142 illustrated in FIG. 8C as route information to the routers 303 to 305. Further, the virtual router function unit 121 advertises the entries 1230 to 1234 to the routers 301 and 302 as route information. As a result, the virtual router function unit 121 ends the route information advertisement process (F2700) shown in FIG.

  29, the virtual router function unit 121 substitutes the value of the current group 855 for the old group 854 in all entries of the PoP information table 146 shown in FIG. 12C (F2212). The PoP information table 146 does not change from the state shown in FIG.

  With the above processing, the virtual router function unit 121 completes the new route acquisition processing (F2800). When a transfer group is divided as shown in the group information table 145 shown in FIG. 11C by the new route acquisition process (F2800), when a packet is input to the transfer apparatus network 10, the result is shown in FIG. 9C. The transfer device 200 of each transfer group is set so that packet transfer is performed according to the group-specific current route information table 1000. Thereby, packet transfer according to the group-specific current route information table 1000 shown in FIG. 9C is realized.

<Example of packet transfer after new route acquisition processing (F2800)>
Next, an example of packet transfer when a packet addressed to the destination network A is input from the router 301 to the transfer apparatus network 10 after the new route acquisition process (F2800) will be described.

  When a packet is input from the router 301, the packet is input to the transfer device 201. The transfer apparatus 201 belongs to PoP501. Referring to the group information table 145 shown in FIG. 11E, the PoP 501 to which the transfer apparatus 201 belongs belongs to the transfer group 2. Further, the transfer apparatus 201 that has received the packet from the router 301 belongs to the transfer group 2 (see the entry 875 in FIG. 12C). In the group-by-group current route information table 1000 shown in FIG. 9C, an entry having the value “2” of the usage group 1001 corresponding to the transfer group 2 and the value of the destination network 1002 being “A” is the entry 1040. It is.

  The preset label transfer table 235 shown in FIGS. 4A, 4B, and 4D and the information recorded in the entry 1040 of the group-specific current route information table 1000 shown in FIG. Originally, the input transfer table 225 of the transfer apparatus 201 shown in FIG. 3B and the output transfer table 245 of the transfer apparatus 202 shown in FIG. The following describes that the packet addressed to A is transferred to the router 302 specified by the value “302” of the advertisement source router 1003 in the entry 1040 of the group-specific current route information table 1000.

  An IP packet with no MPLS label inserted is transferred from the router 301, the packet is input from the router 301 to the transfer apparatus network 10, and the packet is input to the port (2/1) of the transfer apparatus 201. Since the MPLS label is not inserted into the packet input from the physical port 250, the input packet processing unit 220 of the transfer apparatus 201 refers to the input transfer table 225 shown in FIG.

  In FIG. 3B, there is an entry having (2/1) that is the port to which the packet is input in the port number 1301 and the destination network A that is the destination IP address of the input packet in the destination network 1302. Exists in entry 1326. Therefore, the input packet processing unit 220 of the transfer apparatus 201 inserts an MPLS header having an identification label value “601” that is the identification label 1303 of the entry 1326 between the MAC header and the IP header of the input packet. Further, the input packet processing unit 220 of the transfer apparatus 201 inserts an MPLS header having the transfer label value “4001” of the transfer label 1304 of the entry 1326 between the already inserted MPLS header and the MAC header. .

  Further, the input packet processing unit 220 of the transfer apparatus 201 inserts an input port information header in which the port number “(2/1)” at which the packet is input to the transfer apparatus 201 is recorded in the packet. The input packet processing unit 220 of the transfer apparatus 201 passes the packet in which two MPLS labels are inserted to the label transfer processing unit 230.

  The label transfer processing unit 230 of the transfer apparatus 201 uses the port number “(2/1)” in which the value of the input port 1351 is recorded in the input port information header from the label transfer table 235 shown in FIG. And the entry 1361 in which the value of the input transfer label 1352 of the label transfer table 235 is the transfer label value “4001” of the packet is searched.

  The label transfer processing unit 230 of the transfer apparatus 201 rewrites the transfer label value “4001” of the packet with the value “4002” of the output transfer label 1353 of the entry 1363. Then, the label transfer processing unit 230 of the transfer device 201 records the value “(1/1)” of the output port 1354 of the entry 1363 of the label transfer table 235 of the transfer device 201 shown in FIG. The port information header is inserted into the packet and passed to the output packet processing unit 240.

  The output packet processing unit 240 of the transfer device 201 inputs the packet from the label transfer processing unit 230. The output transfer table 245 of the transfer apparatus 201 includes an entry that matches the combination of the destination network address “A” of the input packet, the identification label value “601” inserted in the input packet, and the transfer label value “4002”. do not do.

  Accordingly, the output packet processing unit 240 of the transfer apparatus 201 refers to the port number “(1/1)” recorded in the output port information header, removes the output port information header, and then refers to the port number “(1 / 1) "outputs a packet. The output packet is input to the physical port 250 having the port number (1/1) of the transfer device 206.

  The input packet processing unit 220 of the transfer device 206 inserts an input port information header in which the port number “(1/1)” into which the packet is input is recorded in the packet when the packet in which the MPLS label is inserted is input. Then, the packet is transferred to the label transfer processing unit 230.

  The label transfer processing unit 230 of the transfer device 206 reads the port number “(1) in which the value of the input port 1351 is recorded in the input port information header from the label transfer table 235 of the transfer device 206 shown in FIG. / 1) ”and the entry 1366 in which the value of the input transfer label 1352 is the transfer label value“ 4002 ”of the packet is searched.

  The label transfer processing unit 230 of the transfer device 206 sets the transfer label value “4002” of the packet to the value “4003” of the output transfer label 1353 of the entry 1366 in the label transfer table 235 of the transfer device 206 shown in FIG. Rewrite to The label transfer processing unit 230 of the transfer device 206 inserts an output port information header in which the value “(1/2)” of the output port 1354 of the entry 1366 is recorded into the packet and passes the packet to the output packet processing unit 240.

  Since the transfer device 206 is not connected to the adjacent router 300, there is no entry in the output transfer table 245 of the transfer device 206. Since there is no entry in the output transfer table 245 of the transfer device 206, the output packet processing unit 240 of the transfer device 206 refers to the port number “(1/2)” recorded in the output port information header and outputs the output port information. After removing the header, the packet is output from the referenced port number “(1/2)”. The output packet is input to the physical port 250 having the port number “(1/1)” of the transfer apparatus 202.

  The input packet processing unit 220 of the transfer apparatus 202 records the port number “(1/1)” in which the packet is input to the transfer apparatus 202 when the packet with the MPLS label inserted is input. Is inserted into the packet, and the packet is passed to the label transfer processing unit 230.

  The label transfer processing unit 230 of the transfer device 202 reads the port number “(1) in which the value of the input port 1351 is recorded in the input port information header from the label transfer table 235 of the transfer device 202 shown in FIG. / 1) ”and the entry 1381 whose input transfer label 1352 value is the packet transfer label value“ 4003 ”is searched.

  The label transfer processing unit 230 of the transfer device 202 rewrites the transfer label value “4003” of the packet with the value “4004” of the output transfer label 1353 of the entry 1381. The label transfer processing unit 230 of the transfer device 202 inserts an output port information header in which the value “(2/1)” of the output port 1354 of the entry 1376 is recorded into the packet and passes the packet to the output packet processing unit 240.

  The output packet processing unit 240 of the transfer device 202 inputs the packet from the label transfer processing unit 230. The output transfer table 245 of the transfer device 202 includes the destination network address “A” of the input packet, the identification label value “601” inserted in the packet, and the transfer label value “4004” inserted in the packet. There is an entry 1426 that matches the combination.

  Therefore, the output packet processing unit 240 of the transfer device 202 rewrites the destination MAC address of the packet received from the label transfer processing unit 230 of the transfer device 202 to the value “MAC302” of the rewrite destination MAC 1405 of the entry 1426. Further, the output packet processing unit 240 of the transfer device 202 rewrites the transmission source MAC address of the packet to the value “MAC202” of the rewrite transmission source MAC of the entry 1426. Then, the output packet processing unit 240 of the transfer apparatus 202 removes the identification label and transfer label inserted in the packet. The output packet processing unit 240 of the transfer apparatus 202 refers to the port number “(2/1)” recorded in the output port information header, removes the output port information header, and then refers to the port number “(2/1). ) "Is output from the physical port 250. The output packet is transferred to the router 302 connected to the port number “(2/1)” of the transfer device 202.

  As described above, when a packet addressed to the destination network A is input from the router 301 to the transfer apparatus network 10, the router that is the advertising source router 1003 of the entry 1040 according to the group current path information table 1000 shown in FIG. 9C. 301.

<Example of packet transfer between different groups>
In this embodiment, a certain transfer group can be used even if it is route information obtained by a different transfer group. An example in which a packet is transferred using route information obtained by different transfer groups from a transfer group will be described. Here, as an example, a packet transfer when a packet addressed to the destination network E is input from the router 301 to the transfer apparatus network 10 will be described as an example.

  A packet is input from the router 301 to the transfer apparatus 201. The transfer apparatus 201 belongs to PoP501. Referring to the group information table 145 shown in FIG. 11C, the PoP 501 to which the transfer apparatus 201 belongs belongs to the transfer group 2. Further, the transfer apparatus 201 that has received the packet from the router 301 belongs to the transfer group 2 (see the entry 875 in FIG. 12C). In the group-by-group current route information table shown in FIG. 9C, an entry having the value “2” of the usage group 1001 corresponding to the transfer group 2 and the value of the destination network 1002 being “E” is the entry 1044. is there.

  The value of the information source group 1007 of the entry 1044 is “1”. Therefore, it can be seen that the route information of the entry 1044 is route information obtained from a group different from the group 2 to which the PoP 501 of the transfer apparatus 201 to which the packet is input belongs. Recorded in the preset label transfer table 235 shown in (A), (B), (C), and (E) of FIG. 4 and the entry 1044 of the group-specific current route information table 1000 shown in FIG. 9C. Based on this information, the input transfer table 225 of the transfer apparatus 201 shown in FIG. 3B and the output transfer table 245 of the transfer apparatus 203 shown in FIG. 5C are set.

  Based on the input transfer table 225 of the transfer device 201 shown in FIG. 3B and the output transfer table 245 of the transfer device 203 shown in FIG. 5C, the current route information table for each group 1000 shown in FIG. The following describes that the packet is forwarded to the value “E” of the destination network 1002 to the router 303 specified by the value “303” of the advertisement source router 1003 in the entry 1044.

  The IP packet without the MPLS label inserted is transferred from the router 301, and the packet is input from the router 301 to the transfer apparatus network 10. That is, the packet is input to the port (2/1) of the transfer device 201. Since the MPLS label is not inserted in the packet input from the physical port 250, the input packet processing unit 220 of the transfer device 201 refers to the input transfer table 225 of the transfer device 201 shown in FIG.

  In the input transfer table 225 of the transfer apparatus 201 shown in FIG. 3B, the value of the port number 1301 is the port “(2/1)” into which the packet is input, and the value of the destination network 1302 is input. It exists in the entry 1327 which is the destination IP address “E” of the packet.

  The input packet processing unit 220 of the transfer apparatus 201 inserts an MPLS header having the identification label value “602” of the identification label 1303 of the entry 1327 between the MAC header and the IP header of the input packet. Also, the input packet processing unit 220 of the transfer apparatus 201 sets the MPLS header having the transfer label value “4005” of the transfer label 1304 of the entry 1327 between the already inserted MPLS header and MAC header of the input packet. insert.

  Further, the input packet processing unit 220 of the transfer apparatus 201 inserts an input port information header in which the port number “(2/1)” at which the packet is input to the transfer apparatus 201 is recorded in the packet. The input packet processing unit 220 of the transfer apparatus 201 passes the packet in which two MPLS labels are inserted to the label transfer processing unit 230.

  The label transfer processing unit 230 of the transfer apparatus 201 uses the port number “(2) in which the value of the input port 1351 is recorded in the input port information header from the label transfer table 235 of the transfer apparatus 201 shown in FIG. / 1) ”and the entry 1365 whose input transfer label 1352 value is the packet transfer label value“ 4005 ”is searched for.

  The label transfer processing unit 230 of the transfer apparatus 201 rewrites the transfer label value “4005” of the packet with the value “4006” of the output transfer label 1353 of the searched entry 1365. The label transfer processing unit 230 of the transfer apparatus 201 inserts an output port information header in which the value “(1/1)” of the output port 1354 of the entry 1365 is recorded into the packet, and passes the packet to the output packet processing unit 240.

  The output packet processing unit 240 of the transfer device 201 inputs the packet from the label transfer processing unit 230. The output transfer table 245 (not shown) of the transfer apparatus 201 matches the combination of the destination network address “E” of the input packet, the identification label value “602” inserted in the input packet, and the transfer label value “4006”. No entry exists.

  Accordingly, the output packet processing unit 240 of the transfer apparatus 201 refers to the port number “(1/1)” recorded in the output port information header, removes the output port information header, and then refers to the port number “(1 / 1) "outputs a packet. The output packet is input to the physical port 250 having the port number “(1/1)” of the transfer device 206.

  Since the input packet processing unit 220 of the transfer device 206 has received the packet with the MPLS label inserted, the input packet information header records the port number “(1/1)” at which the packet is input to the transfer device 206. The packet is inserted into the packet and passed to the label transfer processing unit 230.

  The label transfer processing unit 230 of the transfer device 206 reads the port number “(1) in which the value of the input port 1351 is recorded in the input port information header from the label transfer table 235 of the transfer device 206 shown in FIG. / 1) ”and the entry 1370 whose input transfer label 1352 value is the transfer label value“ 4006 ”of the packet is searched.

  The label transfer processing unit 230 of the transfer device 206 rewrites the transfer label value “4006” of the packet with the value “4007” of the output transfer label 1353 of the searched entry 1370. The label transfer processing unit 230 of the transfer device 206 inserts an output port information header in which the value “(1/3)” of the output port 1354 of the entry 1370 is recorded into the packet and passes it to the output packet processing unit 240.

  Since the transfer device 206 is not connected to the adjacent router 300, there is no entry in the output transfer table 245 in the transfer device 206. For this reason, the output packet processing unit 240 of the transfer device 206 refers to the port number “(1/3)” recorded in the output port information header, removes the output port information header, and then refers to the port number “( 1/3) "is output. The output packet is input to the physical port 250 having the port number (1/1) of the transfer device 207.

  The transfer device 207 also performs the same processing as when the input packet processing unit 220, label transfer processing unit 230, and output packet processing unit 240 of the transfer device 207 are the transfer device 206. In this case, the label transfer processing unit 230 of the transfer device 207 refers to the entry 1378 of the label transfer table 235 of the transfer device 207 shown in FIG. The output packet processing unit 240 of the transfer device 207 outputs a packet from the port (1/2) of the transfer device 207. The output packet is input to the physical port 250 having the port number (1/1) of the transfer device 203.

  Since the packet in which the MPLS label is inserted is input, the input packet processing unit 220 of the transfer apparatus 203 uses the input port information header in which the port number “(1/1)” in which the packet is input to the transfer apparatus 203 is recorded. The packet is inserted into the packet and passed to the label transfer processing unit 230.

  The label transfer processing unit 230 of the transfer device 203 uses the port number “(1) in which the value of the input port 1351 is recorded in the input port information header from the label transfer table 235 of the transfer device 203 shown in FIG. / 1) ”and the entry 1388 in which the value of the input transfer label 1352 is the transfer label value“ 4008 ”of the packet is searched.

  The label transfer processing unit 230 of the transfer device 203 rewrites the transfer label value “4008” of the packet with the value “4009” of the output transfer label 1353 of the searched entry 1388. The label transfer processing unit 230 of the transfer device 203 inserts an output port information header in which the value “(2/1)” of the output port 1354 of the entry 1388 is recorded into the packet and passes the packet to the output packet processing unit 240.

  The output packet processing unit 240 of the transfer device 203 receives the destination network address “E” of the packet in which the value of the destination network 1402 is input from the output transfer table 245 of the transfer device 203 shown in FIG. An entry 1440 in which the value of 1403 is the identification label value “602” inserted in the packet and the value of the transfer label 1404 is the transfer label value “4009” inserted in the packet is searched.

  Therefore, the output packet processing unit 240 of the transfer device 203 rewrites the destination MAC address of the packet received from the label transfer processing unit 230 to the value “MAC303” of the rewrite destination MAC 1405 of the entry 1440. Further, the output packet processing unit 240 of the transfer device 203 rewrites the transmission source MAC address of the packet with the value “MAC203” of the rewrite transmission source MAC 1406 and removes the inserted identification label and transfer label. The output packet processing unit 240 of the transfer apparatus 203 refers to the port number “(2/1)” recorded in the output port information header, removes the output port information header, and then refers to the port number “(2/1). ) "Is output from the physical port 250. The output packet is transferred to the router 303 connected to the port number “(2/1)” of the transfer device 203.

  As described above, when a packet addressed to the destination network E is input from the router 301 to the transfer apparatus network 10, the advertising source of the entry 1044 having the destination network E according to the group-specific current route information table 1000 shown in FIG. 9C. The data is transferred to the router 303 specified by the value “303” of the router 1003. As described above, in this embodiment, it is also possible to perform packet transfer using route information obtained by different transfer groups.

  Similarly to the packet transfer example for the entries 1040 and 1044 described above, packets input from the routers 301 to 305 to the transfer device network 10 are recorded in the destination network 1002 in accordance with the group-specific current route information table 1000 shown in FIG. 9C. Forwarded to the connected network.

  Next, description will be made on the fact that, by dividing the transfer group into two, packets are transferred through a path having a lower cost value than when the transfer group is not divided.

  A case where a packet addressed to the network address A is input from the router 301 to the transfer apparatus network 10 through the PoP 501 will be described as an example. The route information for reaching the network address “A” in the route information table 141 shown in FIG. 7C which is the route information held by the virtual router function unit 121 is entries 1156 and 1159. When the transfer group is not divided, the route information to be used is determined as one.

  Here, when it is determined that the route information of the entry 1159 is used, the value of the advertisement source router 1102 of the entry 1159 is “304”, so the packet is transmitted from the PoP 504 (value of the information source PoP 1105) connected to the router 304. Is output.

  Looking at the path management table 149, the path passing through the routers 301 and 304 is a path having a path ID 751 value of “603” (entry 777). Thus, the packet is forwarded through path 603. The value of the inter-path cost 755 of this entry 777 is “400”.

  On the other hand, by dividing the forwarding group into two, the virtual router function unit 121 holds the group-specific current route information table 1000 shown in FIG. 9C. The PoP 501 that receives a packet from the router 301 belongs to the transfer group 2 (the group information table 145 in FIG. 11E). A packet whose destination network 1002 is “A” is output from the PoP 502 (value of the information source PoP 1006) connected to the router 302 because the value of the advertisement source router 1003 is “302”.

  Looking at the path management table 149, the path passing through the routers 301 and 302 is a path whose path ID 751 is “601” (entry 775). Thus, the packet is forwarded through path 601. Further, the value of the cost 755 between paths of this entry 775 is “200”. Thus, it can be seen that the cost value is halved (400 to 200) by dividing the transfer group into two.

Further, a case where a packet addressed to the network address B is input from the router 305 through the PoP 504 to the transfer apparatus network 10 will be described as an example. In the route information table 141 shown in FIG. 7C, which is route information held by the virtual router function unit 121, the route information for reaching the network address B is entries 1157 and 1160. When the transfer group is not divided, the route information to be used is determined as one.

  Here, when it is determined that the route information of the entry 1157 is used, the value of the advertisement source router 1003 of the entry 1157 is “302”, so that the packet is transmitted through the PoP 502 (value of the information source PoP 1105) connected to the router 302. Is output.

Looking at the path management table 149, the path passing through the routers 305 and 302 is a path whose path ID 751 value is “607” (entry 781). Thus, the packet is forwarded through path 607. Further, the value of the inter-path cost 755 of this entry 781 is “401”.

  On the other hand, by dividing the forwarding group into two, the virtual router function unit 121 holds the group-specific route information database 143 shown in FIG. 9C. The PoP 504 that receives the packet from the router 301 belongs to the transfer group 1 (the group information table 145 in FIG. 11E). A packet whose destination network 1002 is “B” is output from the PoP 504 (value of the information source PoP 1006) connected to the router 304 because the value of the advertisement source router 1003 is “304”.

  Looking at the path management table 149 shown in FIG. 15, the path passing through the routers 305 and 304 is a path whose path ID 751 value is “610” (entry 784). Thus, the packet is forwarded through path 610. The value of the inter-path cost 755 of this entry 784 is “1”. Thus, it can be seen that the cost value is reduced to about 1/4 (from 401 to 1) by dividing the transfer group into two.

  Thus, by dividing the transfer group according to the present embodiment, packets are transferred through a path with a low cost value. In this embodiment, the cost value of the path is the distance between the physical links constituting the path. Since the packet is transferred through the path having a low cost value, the packet is transferred as much as possible between the same transfer groups having a short distance between the transfer devices. Therefore, the packet transfer time is shortened, and transmission delay can be suppressed.

  In addition, by configuring a transfer group with transfer devices that are close in distance, packets are transferred through a path with a low cost value. Therefore, the usage rate of the long distance link with high equipment cost and management cost decreases, and it becomes possible to suppress the addition of the long distance link. As described above, even when a plurality of transfer devices are centrally controlled as a single router, a single output port is not determined for a certain destination as a whole, and the packet input port is considered after considering the transfer device network. Packets can be sent through a nearby output port.

<Example of automatic setting of PoP priority>
Next, an example of automatically setting the PoP priority will be described. The control server 100 monitors the load (for example, communication bandwidth and CPU usage rate) of each transfer device 200. The control server 100 acquires the load of the transfer device 200 from each transfer device 200, and changes the PoP priority of the PoP 500 to which each transfer device 200 belongs according to the acquired load. When there are a plurality of transfer devices 200 in the PoP 500, the load of the transfer device 200 with the higher load may be adopted, or the average value of the loads of the transfer devices 200 in the PoP 500 may be adopted.

  For example, when the load in the transfer device 200 in a certain PoP 500 becomes lower than the lower limit value, the control server 100 may set the PoP priority higher than the current PoP priority. Further, when the load becomes higher than the upper limit value, the PoP priority may be set lower than the current PoP priority. Note that the amount of fluctuation of the PoP priority may be a preset amount or an amount corresponding to the amount of fluctuation of the load.

  Further, the control server 100 may periodically acquire information indicating the load from the transfer device 200. Further, the transfer device 200 may transmit information indicating the load to the control server 100 at a timing when the load becomes lower than the lower limit value or at a timing when the load becomes higher than the upper limit value.

  When the control server 100 acquires information indicating the load, the control server 100 recalculates the value of the PoP priority 852 for each PoP 500. For example, when the load of the PoP 504 in the entry 878 becomes larger than the upper limit value, the control server 100 subtracts a predetermined amount (for example, 5 points) from the PoP priority. On the other hand, when the load of the PoP 501 in the entry 875 becomes lower than the lower limit value, the control server 100 adds a predetermined amount (for example, 5 points) to the PoP priority.

  When the value of the PoP priority 852 is recalculated, the control server 100 sorts the entries 875 to 878 in descending order of the value of the PoP priority 852. When there is a change in the order of the entries 875 to 878 before and after the sorting, the control server 100 again executes (1) grouping processing, (2) route advertisement processing by router connection, and (3) new route acquisition processing. Thereby, appropriate grouping can be automatically performed according to the PoP priority 852.

<Difference from VRF>
One technique for dividing one router into a plurality of forwarding groups and having a different routing table for each forwarding group is VRF (Virtual Routing and Forwarding). The VRF can create a plurality of independent routing tables on one router, and a plurality of virtual routers appear to operate on one router.

  In the VRF, a plurality of independent routing tables are realized by combining a group identifier and an IP address on one routing table, and the IP network space handled according to different groups is virtually I know. In the VRF, route information used for creating a routing table is different between a plurality of virtual routers. The VRF divides network space by dividing path information that can be used by virtually creating a plurality of virtual routers on one router.

  In contrast, in this embodiment, a different routing table is created for each transfer group, but the routing information used to create the routing table is common to a plurality of transfer groups, and unlike a VRF, a plurality of routing tables are used. The same IP network space is handled in the group.

  In this embodiment, packets are transferred as much as possible within the same transfer group in which the distance between the transfer apparatuses 200 is short. In this embodiment, route information acquired by different transfer groups can also be used. In this embodiment, a virtual router that can be seen as a single router is adopted from the viewpoint of surrounding devices. If an attempt is made to show a plurality of virtual routers as the same router in the VRF, the plurality of virtual routers cannot exchange route information as there are a plurality of the same routers as their own routers. Therefore, the transfer grouping as in the present embodiment cannot be realized with the VRF.

  In this way, in this embodiment, the control server virtually shows a transfer device network composed of a plurality of transfer devices as one router, connects a plurality of transfer devices and routers existing outside thereof, Transfer device 1 is divided into several transfer groups, and a transfer system 1 is constructed that performs packet transfer according to a group-specific route information database 143 that creates packets input to the transfer device network according to the transfer group to which the transfer device belongs. .

  Since the group-specific route information database 143 has different entries for each transfer group in the group-specific current route information table 1000, a packet of a destination that has entered the transfer device network is the address of the transfer device that received the packet from the outside. When transfer is possible from any of the belonging group and other groups, it is possible to transfer via the route within the belonging group. As a result, it is possible to suppress transmission delay caused by passing through a route of another group.

  When dividing this transfer group, by grouping the transfer devices so that the distance of the physical line between the transfer devices is shortened, packets are transferred as much as possible within the same transfer group where the distance between the transfer devices is close, Packet transfer between groups with a long distance between transfer devices is suppressed. This makes it possible to suppress the addition of expensive long-distance lines.

  The present invention is not limited to the above-described embodiments, and includes various modifications and equivalent configurations within the scope of the appended claims. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and the present invention is not necessarily limited to those having all the configurations described. A part of the configuration of one embodiment may be replaced with the configuration of another embodiment. Moreover, you may add the structure of another Example to the structure of a certain Example. Moreover, you may add, delete, or replace another structure about a part of structure of each Example.

  In addition, each of the above-described configurations, functions, processing units, processing means, etc. may be realized in hardware by designing a part or all of them, for example, with an integrated circuit, and the processor realizes each function. It may be realized by software by interpreting and executing the program to be executed.

  Information such as programs, tables, and files that realize each function can be stored in a storage device such as a memory, a hard disk, and an SSD (Solid State Drive), or a recording medium such as an IC card, an SD card, and a DVD.

  Further, the control lines and the information lines are those that are considered necessary for the explanation, and not all the control lines and the information lines that are necessary for the mounting are shown. In practice, it can be considered that almost all the components are connected to each other.

1 Transfer system 10 Transfer device network (virtual router)
100 Control server 120 Processing unit 140 Storage unit 141 Route information table 142 Differential route information table 143 Route information database by group 144 Neighboring router management table 145 Group information table 146 Differential route information table 147 Forwarding device information table 148 Physical link information table 149 Path Management table 200 Transfer device 300 Router 400 Physical link 500 PoP
600 network

Claims (9)

A control server configured to control a transfer device network configured by a plurality of transfer devices that transfer data and connected to a router group,
The control server includes a processor that executes a program, a memory that stores the program, a communication interface that communicates with the router group via the plurality of transfer devices and the plurality of transfer devices,
The processor is
A grouping process for grouping the connection points into a plurality of groups based on the priority set for each of the plurality of connection points in the transfer device network to which at least one of the plurality of transfer devices belongs. When,
For each group grouped by the grouping process, a destination that is reached from the transmission source via the transfer device network, a router that advertises the destination, and a connection point to which the transfer device connected to the router belongs And a generation process for generating route information for specifying
A setting process for setting the plurality of transfer apparatuses via the communication interface so that the plurality of transfer apparatuses transfer data according to the path information generated by the generation process;
Advertising processing for advertising the route information to the router specified by the route information via the communication interface;
A control server characterized by executing In the grouping process, the processor groups the first connection points having a priority higher than a predetermined value among the plurality of connection points into the plurality of groups based on the priority,
The processor is
The first transfer apparatus belonging to the first connection point grouped by the grouping process, and the second transfer point belonging to the second connection point of which the priority is equal to or lower than the predetermined value among the plurality of connection points In the combination with the second transfer device, the combination indicating that the cost indicating the distance between the first transfer device and the second transfer device is not the maximum or less than the threshold is selected, and the selected combination is configured. 2. The control server according to claim 1, wherein a distribution process of distributing the second transfer devices that constitute the selected combination to a group to which the first transfer device belongs is executed.   3. The control server according to claim 2, wherein, in the distribution process, the processor selects a combination that minimizes the cost in a combination of the first transfer device and the second transfer device. 4. .   In the generation process, when a plurality of route information having the same destination is generated, the processor performs grouping by the grouping process among the belonging groups of connection points respectively included in the plurality of route information. The control server according to claim 1, wherein route information that is the same group as the group that has been set is selected as route information that is a setting target of the setting process.   In the generation process, when a plurality of pieces of route information having the same destination are generated, the processor selects the plurality of pieces of route information from the plurality of pieces of route information based on the priorities included in the plurality of pieces of route information. The control server according to claim 1, wherein route information to be set in setting processing is selected.   When there is a change in the order based on the priority of the connection point due to the change in the priority, the processor, based on the priority after the change, the grouping process, the generation process, the setting process, and the The control server according to claim 1, wherein advertisement processing is re-executed. A transfer system for transferring data,
The transfer system includes a transfer device network configured by a plurality of transfer devices that transfer the data and connected to a router group, and a control server that controls the transfer device network,
The control server
A grouping process for grouping the connection points into a plurality of groups based on the priority set for each of the plurality of connection points in the transfer device network to which at least one of the plurality of transfer devices belongs. When,
For each group grouped by the grouping process, a destination that is reached from the transmission source via the transfer device network, a router that advertises the destination, and a connection point to which the transfer device connected to the router belongs And a generation process for generating first route information for specifying
A setting process for setting the plurality of transfer devices to transfer the data according to the first path information generated by the generation process;
Advertising processing for advertising the first route information to the router specified by the first route information;
A control unit for executing
Each of the plurality of transfer devices includes:
Transferring the second route information held by the router group advertised from the router group to which each of the plurality of transfer devices is connected to the control server;
The controller is
When receiving the second route information from any one of the plurality of transfer devices,
In the generation process, the first route information is generated based on a connection point to which a transfer device that transferred the second route information belongs and the second route information. When the control unit receives a plurality of the second route information including information on the same destination from the plurality of transfer devices,
In the generation process, among the second route information including a plurality of received information on the same destination, a connection with a high priority of a connection point to which each of a plurality of transfer devices that transferred the second route information belongs The transfer system according to claim 7, wherein the second route information transferred by the transfer device belonging to the point is used for generating the first route information. A control server setting method for controlling a transfer device network configured by a plurality of transfer devices for transferring data and connected to a router group,
The control server includes a processor that executes a program and a memory that stores the program,
The setting method is as follows:
The processor is
A grouping process for grouping the connection points into a plurality of groups based on the priority set for each of the plurality of connection points in the transfer device network to which at least one of the plurality of transfer devices belongs. When,
For each group grouped by the grouping process, a destination that is reached from the transmission source via the transfer device network, a router that advertises the destination, and a connection point to which the transfer device connected to the router belongs And a generation process for generating route information for specifying
A setting process for setting the plurality of transfer devices to transfer according to the route information generated by the generation process; and
Advertising processing for advertising the route information to the router specified by the route information;
The setting method characterized by performing.

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