JP2017183960A - Switch control device, method and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a switch control device which, if accesses are concentrated to a terminal connected to a switch, can prevent an increased number of flow entries set to the switch.SOLUTION: Flow entry set means 52 sets to a relay switch a flow entry which prescribes that a packet, having a destination address which corresponds to a subnetwork address supported by a gateway switch, shall be transferred to the gateway switch. Also, flow entry set means 52, on receiving a packet from the gateway switch, sets to the gateway switch a flow entry which prescribes to transfer a packet, having a terminal thereof as a transmission source, and a destination address which corresponds to the subnetwork address supported by the gateway switch, to the relay switch, for each gateway switch other than the gateway switch concerned.SELECTED DRAWING: Figure 15

Description

  The present invention relates to a switch control device, a switch control method, and a switch control program for controlling a switch that transfers a packet.

  An open flow (OpenFlow) is known as a protocol in which a control device controls a switch for transferring a packet.

  In the open flow, the control device sets a flow entry in the switch. Then, the switch processes the received packet according to the flow entry. The flow entry is information that defines how to process a packet (for example, where to transfer the packet). The flow entry is set for each packet flow. When the switch receives a packet and there is a flow entry corresponding to the flow of the packet, the switch processes the packet according to the flow entry. On the other hand, when there is no flow entry corresponding to the flow of the received packet, the switch transmits the packet to the control device. Then, the control device determines a flow entry corresponding to the flow of the packet and sets it in the switch.

  Examples of messages transmitted and received between the control device and the switch in the open flow include “packet in (Packet_in)” and “packet out (Packet_out)”.

  “Packet-in” is a message sent from the switch to the control device. “Packet-in” is used to send a packet for which no corresponding flow entry exists from the switch to the control device.

  “Packet out” is a message sent from the control device to the switch. “Packet out” is a message instructing packet output from the port.

  Each switch is connected to the control device through a dedicated path. This dedicated path is called a control channel. The control device communicates with individual switches via a control channel.

  Patent Document 1 describes a technique related to a function distribution type packet transfer processing apparatus in which a control signal processing unit and a data signal processing unit physically distributed on a network cooperate to perform packet transfer processing.

JP 2008-54129 A

  In this specification, a device connected to a switch and serving as a packet transmission source or destination is referred to as a terminal.

  In a network including a switch controlled by OpenFlow, access from other terminals may concentrate on a terminal connected to any switch.

  In a switch to which a terminal to which access is concentrated is connected, it is necessary to set flow entries for the number of terminals that are communication partners of the terminal. At this time, if the number of terminals that are communication partners is large, a large number of flow entries need to be set in the switch. Further, when the number of flow entries exceeds the number of flow entries that can be set in the switch, there may be a flow entry that cannot be set in the switch.

  FIG. 16 is a schematic diagram illustrating an example of a network configuration in which access concentrates on one terminal. In FIG. 16, a DNS (Domain Name System) server is illustrated as an example of a terminal where access is concentrated. Further, the case where the other terminal is a personal computer (hereinafter referred to as PC) is illustrated. In the following description, the control device in the open flow is denoted as OFC, and the switch in the open flow is denoted as OFS.

  In FIG. 16, the packet communication path is indicated by a solid line, and the control channel is indicated by a broken line. The numbers marked with # are OFS port numbers. The OFC 7 sets flow entries in the OFS 1 to 5. In the example illustrated in FIG. 16, accesses from the n PCs 10 a to 10 n are concentrated on the DNS server 20. In this case, it is necessary to set n flow entries in the OFS 4 to which the DNS server 20 is connected. Further, when m terminals with concentrated access are connected to the OFS 4, it is necessary to set n × m flow entries in the OFS 4.

  FIG. 17 is a schematic diagram showing each flow entry set in the OFS 4 to which the DNS server 20 is connected. In FIG. 17, an action corresponding to a set of a source MAC (Media Access Control) address and a destination MAC address is shown for each destination PC. “Port # 1” shown as an action means that a packet is output from port # 1. If the number of PCs is n, n flow entries are set in OFS4. When the number of PCs is large, it is necessary to set a large number of flow entries in the OFS 4 as described above, or flow entries that cannot be set in the OFS 4 are generated.

  In order to reduce the number of flow entries set in the OFS 4, it is conceivable to distribute the DNS server 20 to a plurality of OFSs, but in that case, the difficulty of network design becomes high.

  Therefore, the present invention provides a switch control device, a switch control method, and a switch control device capable of preventing an increase in the number of flow entries set in a switch even when access is concentrated on a terminal connected to the switch. An object is to provide a switch control program.

  A switch control apparatus according to the present invention sets a flow entry that defines an action for a packet in a gateway switch that is a switch associated with a subnetwork and a relay switch that relays the packet between gateway switches. And the flow entry setting means relays a flow entry that specifies that a packet whose destination address corresponds to the address of the subnetwork corresponding to the gateway switch is forwarded to the gateway switch. Set for each gateway switch other than the switch, when a packet is received from the gateway switch, the packet destined to the terminal that sent the packet is forwarded to that terminal. In addition to setting a flow entry that specifies the destination address for the gateway switch, the destination address corresponds to the address of the sub-network corresponding to the gateway switch for each gateway switch other than the gateway switch. It is characterized by setting a flow entry that defines that a packet to be transferred to a relay switch.

  In addition, the switch control method according to the present invention provides a sub-network corresponding to a gateway switch with respect to a relay switch in which a switch control device that controls the switch relays packets between gateway switches that are switches associated with the sub-network. A flow entry that specifies that a packet whose destination address corresponds to that address is forwarded to the gateway switch is set for each gateway switch other than the relay switch, and when the packet is received from the gateway switch, the gateway switch Set a flow entry that specifies that a packet destined for the terminal of the packet source is forwarded to that terminal, and sets a gateway other than the gateway switch to the gateway switch. For each switch, and the terminal as the transmission source, and sets a flow entry that destination address to the address of the sub-network corresponding to the gateway switch has provisions to forward packets that correspond to a relay switch.

  The switch control program according to the present invention is a switch control program installed in a computer that controls a switch, and is a relay switch that relays packets between gateway switches that are switches associated with a subnetwork. On the other hand, a process for setting a flow entry that specifies that a packet whose destination address corresponds to a subnetwork address corresponding to the gateway switch is transferred to the gateway switch for each gateway switch other than the relay switch, and When a packet is received from a gateway switch, a flow entry that specifies that the packet destined for the packet source terminal is forwarded to the terminal is set for the gateway switch. For the gateway switch, for each gateway switch other than the gateway switch, a packet whose destination address corresponds to the address of the subnetwork corresponding to the gateway switch is forwarded to the relay switch. A process for setting a prescribed flow entry is executed.

  According to the present invention, it is possible to prevent an increase in the number of flow entries set in a switch even when access concentrates on a terminal connected to the switch.

It is a schematic diagram which shows the example of a management object network. It is a block diagram which shows the structural example of the switch control apparatus of this invention. It is explanatory drawing which shows the example of the information which a switch control apparatus memorize | stores as GWS information. It is explanatory drawing which shows the example of the flow entry which a flow setting process part sets with respect to a relay switch. It is explanatory drawing which shows the example of process progress when the address of the terminal which communicates corresponds to the address of the subnetwork corresponding to GWS connected to the terminal. It is explanatory drawing which shows the example of process progress when the address of the terminal which communicates corresponds to the address of the subnetwork corresponding to GWS connected to the terminal. It is explanatory drawing which shows the example of the flow entry set by step S3. It is explanatory drawing which shows the example of the flow entry set by step S8. It is explanatory drawing which shows the example of a process progress when the address of the terminal which communicates does not correspond to the address of the subnetwork corresponding to GWS connected to the terminal. It is explanatory drawing which shows the example of a process progress when the address of the terminal which communicates does not correspond to the address of the subnetwork corresponding to GWS connected to the terminal. It is explanatory drawing which shows the example of a process progress when the address of the terminal which communicates does not correspond to the address of the subnetwork corresponding to GWS connected to the terminal. It is explanatory drawing which shows the example of the flow entry set by step T3a. It is explanatory drawing which shows the example of the flow entry set by step T3b. It is explanatory drawing which shows the example of the flow entry set by step T8. It is a block diagram which shows the outline | summary of the switch control apparatus of this invention. It is a schematic diagram which shows the example of a network structure where access concentrates on one terminal. It is a schematic diagram which shows each flow entry set to OFS to which the DNS server shown in FIG. 16 is connected.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  As described above, in this specification, a device connected to a switch and serving as a packet transmission source or destination is referred to as a terminal.

  The switch control device of the present invention corresponds to a control device in open flow. Also in the following description, the control device in the open flow is denoted as OFC, and the switch in the open flow is denoted as OFS.

  The switch control device of the present invention divides the IP (Internet Protocol) address band of the management target network into a plurality of sub-networks. Then, the switch control device associates the IP address (IP address bandwidth) of the divided subnetwork with the OFS. The OFS associated with the IP address of the subnetwork is referred to as a gateway switch or GWS (Gateway Switch).

  A switch that relays packets between GWSs is referred to as a relay switch. The relay switch may be GWS.

  FIG. 1 is a schematic diagram illustrating an example of a management target network. In FIG. 1, a route indicated by a solid line and a route indicated by an alternate long and short dash line are packet transfer routes. A route indicated by a solid line is a route used when transferring a packet via a relay switch. The route indicated by the alternate long and short dash line is a route used when a packet is directly transferred between GWSs without going through a relay switch. A path indicated by a broken line is a control channel. Note that the topology of the managed network is not limited to the topology shown in FIG. In FIG. 1, the numbers marked with # are OFS port numbers.

  The switch control apparatus (OFC) 700 of the present invention sets a flow entry for each of the OFS 100-500.

  The OFSs 100, 200, 300, 400, and 500 are assumed to be GWS.

  The OFS 500 is a relay switch that relays packets between GWSs. In the example shown in FIG. 1, the ports # 1, # 2, # 3, and # 4 of the relay switch (OFS 500) are connected to the OFSs 100, 200, 300, and 400, respectively.

  In the example illustrated in FIG. 1, PCs 11 a and 11 b are connected to the OFS 100 as terminals. A PC is also connected to the OFS 200, 300 as a terminal. A DNS server 30 is connected to the OFS 400 as a terminal.

  The PC 11a is connected to the port #X of the OFS 100. The PC 11b is connected to the port #Y of the OFS 100. DNS server 30 is connected to port #Z of OFS 400.

  The OFS 100 is connected to the port #W of the OFS 200.

  In FIG. 1, addresses described in the vicinity of the OFS 100, 200, 300, and 400 are subnetwork addresses corresponding to the OFS 100, 200, 300, and 400, respectively.

  In the following description, the OFS 100 to 500 shown in FIG.

  The switch control device 700 sets a flow entry in which an action is associated with a set of a transmission source MAC address and a subnetwork IP address corresponding to the GWS in the GWS connected to the terminal.

  FIG. 2 is a block diagram showing a configuration example of the switch control device of the present invention. The switch control device 700 of the present invention includes a communication processing unit 305, a configuration setting unit 310, a configuration information management unit 320, a flow setting processing unit 340, a route calculation processing unit 350, a topology information receiving unit 360, a topology An information management unit 370, a station information reception unit 390, a station information management unit 405, and a GWS management unit 430 are provided.

  The communication processing unit 305 is a communication interface for communicating with each OFS. For example, the communication processing unit 305 transmits / receives a packet to / from each OFS.

  The configuration setting unit 310 is a user interface for writing configuration information to the configuration information management unit 320. The configuration information is information indicating the IP address bandwidth of the management target network.

  The configuration information management unit 320 includes, for example, a memory, and writes configuration information (IP address band of the management target network) designated by the user via the configuration setting unit 310 into the memory.

  When the switch control device 700 and each OFS are connected, each OFS detects the topology of the OFS network by a standard method such as LLDP (Link Layer Discovery Protocol) and notifies the switch control device 700 of the topology information. To do. The topology information reception unit 360 receives the topology information notified from each OFS via the communication processing unit 305 and instructs the topology information management unit 370 to write the topology information.

  The topology information management unit 370 includes, for example, a memory, and writes the topology information received from each OFS by the topology information receiving unit 360 in accordance with instructions from the topology information receiving unit 360.

  The route calculation processing unit 350 acquires the configuration information 330 from the configuration information management unit 320 and acquires the topology information 380 from the topology information management unit 370. As described above, the configuration information 330 is information indicating the IP address bandwidth of the management target network. Based on the topology information 380 and the configuration information 330, the route calculation processing unit 350 determines which OFS in the managed network is the GWS, and how to divide the IP address bandwidth of the managed network To decide. Further, the route calculation processing unit 350 determines which subnetwork IP address (IP address bandwidth) obtained by the division is associated with the OFS determined as GWS. Information indicating the above contents determined by the route calculation processing unit 350 is referred to as GWS information. The route calculation processing unit 350 instructs the GWS management unit 430 to write the GWS information 420.

  The GWS management unit 430 includes a memory, for example, and writes the GWS information 420 in the memory according to an instruction from the route calculation processing unit 350.

  FIG. 3 is an explanatory diagram illustrating an example of information stored as the GWS information 420 by the switch control device (OFC) 700. In FIG. 3, for example, it means that OFS 100, 200, 300, 400 is determined as GWS. For example, this means that the OFS 100 is associated with a subnetwork whose IP address bandwidth is “192.168.0.0/26”. In addition, the route calculation processing unit 350 may determine the OFS 500 as GWS.

  The route calculation processing unit 350 also determines a relay switch based on the topology information 380 and instructs the GWS management unit 430 to write information indicating the OFS corresponding to the relay switch. In the present embodiment, a case where the OFS 500 is determined as a relay switch will be described as an example.

  When the GWS connected to the terminal receives a packet from the terminal and the flow entry corresponding to the packet is not set in the GWS, the GWS sends the packet to the switch control apparatus 700 together with the “packet in” message. Send. At this time, the GWS also transmits station information to the switch control device 700. The station information is information indicating a set of a MAC address of a packet transmission source terminal and a DPID (Datapath ID) / port number of an OFS connected to the terminal.

  The station information reception unit 390 receives the station information notified from each OFS to which the terminal is connected via the communication processing unit 305 and instructs the station information management unit 405 to write the station information.

  The station information management unit 405 includes a memory, for example. Then, the station information management unit 405 writes the station information received by the station information receiving unit 390 from each OFS to which the terminal is connected in the memory according to the instruction of the station information receiving unit 390. It can be said that the station information indicates an address (MAC address) of a terminal connected to the GWS. Therefore, the station information management unit 405 can also be referred to as a terminal address storage unit that stores the address of a terminal connected to the GWS.

  The flow setting processing unit 340 receives, via the communication processing unit 305, a packet transmitted by the OFS to which the terminal is connected together with the “packet in” message. Then, the flow setting processing unit 340 sets the OFS that transmitted the packet based on the station information transmitted together with the “packet-in” message, the topology information 380 and the GWS information 420 known by the route calculation processing unit 350. A flow entry to be generated is generated. Then, the flow setting processing unit 340 sets the flow entry in the OFS by transmitting the flow entry to the OFS via the communication processing unit 305.

  The configuration information management unit 320, the topology information reception unit 360, the topology information management unit 370, the station information reception unit 390, the station information management unit 405, the route calculation processing unit 350, the GWS management unit 430, and the flow setting processing unit 340 are, for example, It is realized by a CPU of a computer that operates according to a switch control program. In this case, for example, the CPU reads a switch control program from a program recording medium such as a program storage device (not shown) of the computer, and in accordance with the switch control program, the configuration information management unit 320, the topology information reception unit 360, and the topology information management. The unit 370, the station information reception unit 390, the station information management unit 405, the route calculation processing unit 350, the GWS management unit 430, and the flow setting processing unit 340 may be operated. Further, the configuration information management unit 320, the topology information reception unit 360, the topology information management unit 370, the station information reception unit 390, the station information management unit 405, the route calculation processing unit 350, the GWS management unit 430, and the flow setting processing unit 340 are separately provided. It may be realized by hardware.

  Next, an example of processing progress of the present invention will be described.

  First, a process corresponding to advance preparation will be described. The configuration information management unit 320 is designated with configuration information from the user of the switch control device 700 via the configuration setting unit 310. Then, the configuration information management unit 320 writes the configuration information in the memory. As a result, the configuration information management unit 320 stores, for example, configuration information indicating that the IP address bandwidth of the management target network is “192.168.0.0/24 (see FIG. 1)”.

  When the switch control device 700 and each OFS are connected, each OFS detects the topology of the OFS network by a standard method such as LLDP and notifies the switch control device 700 of the topology information. The topology information reception unit 360 instructs the topology information management unit 370 to write the topology information notified from each OFS. The topology information management unit 370 writes the topology information in the memory according to this instruction. As a result, the topology information management unit 370 stores the topology information of the network of the OFS.

  After the configuration information and the network topology information of the OFS are stored, the route calculation processing unit 350 determines which OFS in the managed network is the GWS based on the topology information and the configuration information. And how to divide the IP address bandwidth of the managed network. Further, the route calculation processing unit 350 determines which subnetwork IP address (IP address bandwidth) obtained by the division is associated with the OFS determined as GWS. The route calculation processing unit 350 instructs the GWS management unit 430 to write the GWS information 420 indicating the determination result. In this example, it is assumed that OFS 100, 200, 300, 400, and 500 are determined as GWS. Further, it is assumed that the correspondence between the OFS 100, 200, 300, 400 and the IP address of the subnetwork is determined as shown in FIG.

  The route calculation processing unit 350 also determines a relay switch based on the topology information, and instructs the GWS management unit 430 to write information indicating the OFS corresponding to the relay switch. In the present embodiment, description will be made assuming that the switch 500 is determined as a relay switch.

  When the correspondence between the GWS and the IP address of the subnetwork and the relay switch are determined, the flow setting processing unit 340 corresponds to the IP address (IP address band) of the subnetwork corresponding to the GWS and the IP address. A flow entry that defines an action is created for each GWS (except for OFS 500, which is a relay switch), and the flow entry is set in the relay switch (OFS 500). The flow setting processing unit 340 describes that the packet is transferred to the GWS corresponding to the IP address described in the flow entry as an action.

  An example of a flow entry that the flow setting processing unit 340 sets for the relay switch (OFS 500) is shown in FIG. In FIG. 4, for example, “Port # 1” means that a packet is output from port # 1. For example, the first flow entry shown in FIG. 4 stipulates that a packet whose destination address corresponds to “192.168.0.0/26” is output from port # 1. Port # 1 of the OFS 500 is connected to the OFS 100 (see FIG. 1). Therefore, outputting a packet from port # 1 of the OFS 500 means transferring the packet to the OFS 100. Here, the first flow entry shown in FIG. 4 has been described as an example, but the other three flow entries shown in FIG. 4 are similar flow entries corresponding to OFS 200, 300, and 400.

  The flow setting processing unit 340 sends to the relay switch a flow entry that specifies that a packet whose destination address corresponds to the address of the subnetwork corresponding to the GWS is transferred to the GWS for each GWS other than the relay switch. It is set to. The flow setting processing unit 340 does not need to set a flow entry in the OFS 500 that specifies that the packet is transferred toward the OFS 500.

  The above is the process corresponding to the advance preparation.

  Next, processing progress when communication between terminals occurs will be described. Here, a case will be described first where the address of a terminal that performs communication corresponds to the address of a subnetwork corresponding to the GWS connected to the terminal.

  5 and 6 are explanatory diagrams illustrating an example of processing progress when the address of a terminal that performs communication corresponds to the address of a subnetwork corresponding to the GWS connected to the terminal. 5 and 6 are diagrams in which a part of FIG. 1 is extracted and step numbers are added.

  Here, the IP address of the PC 11a corresponds to the IP address of the subnetwork corresponding to the GWS (OFS 100) to which the PC 11a is connected, and the IP address of the DNS server 30 is the GWS (OFS 400 to which the DNS server 30 is connected). ) Is assumed to correspond to the IP address of the sub-network corresponding to.

  First, the PC 11a transmits a packet having the PC 11a as a transmission source and the DNS server 30 as a destination to the OFS 100 (step S1 shown in FIG. 5).

  It is assumed that the flow entry corresponding to this packet has not been set in the OFS 100 yet. In this case, the OFS 100 transmits the packet together with the “packet in” message to the switch control device 700 (step S2 shown in FIG. 5). At this time, the OFS 100 also transmits station information regarding the PC 11a and the OFS 100 to the switch control device 700.

  Upon receiving the packet and station information, the flow setting processing unit 340 of the switch control device 700 creates a flow entry to be set in the OFS 100 that has transmitted the “packet in” message, and sets the flow entry in the OFS 100 ( Step S3) shown in FIG. FIG. 7 is an explanatory diagram illustrating an example of a flow entry set in the OFS 100 in step S3.

  From the station information received from the OFS 100, the flow setting processing unit 340 recognizes that the PC 11a that is the packet transmission source terminal is connected to the port #X of the OFS 100. Based on the station information, the flow setting processing unit 340 sets, in the OFS 100, a flow entry that stipulates that a packet destined for the packet transmission source terminal (PC 11a in this example) is transferred to the terminal. . The first flow entry shown in FIG. 7 is this flow entry. The first flow entry shown in FIG. 7 specifies that a packet whose destination MAC address and destination IP address match the MAC address and IP address of PC 11a is output from port #X (that is, transferred to PC 11a). Yes.

  Further, the flow setting processing unit 340 forwards, to the OFS 100, a packet whose destination is the address of the subnetwork corresponding to the GWS and the destination address for each GWS other than the OFS 100 to the relay switch. Set the flow entry that stipulates to do. The three flow entries from the second to the fourth shown in FIG. 7 are this flow entry. For example, in the second flow entry shown in FIG. 7, the source MAC address is the MAC address of the PC 11a, and the destination IP address corresponds to the address of the subnetwork corresponding to the OFS 200 (“192.168.0.64/26”). It defines that a packet is output from port # 1 (that is, transferred to a relay switch). The third and fourth flow entries shown in FIG. 7 are similar flow entries corresponding to the OFSs 300 and 400.

  Further, the station information reception unit 390 of the switch control device 700 stores the station information received from the OFS 100 in the station information management unit 405.

  After step S3, the flow setting processing unit 340 stores in the station information management unit 405 which port of which GWS the terminal having the destination MAC address of the packet received together with the “packet in” message is connected. The inspection is performed based on the station information 410 being present. However, here, the terminal (DNS server 30) having the packet destination MAC address does not transmit the station information to the switch control device 700. For this reason, the flow setting processing unit 340 cannot identify which port of which GWS the terminal having the destination MAC address of the packet received together with the “packet in” message is connected. In this case, the flow setting processing unit 340 transmits the packet received from the OFS 100 in step S2 and the “packet out” message indicating that the packet is broadcasted to all the GWSs (step S4 illustrated in FIG. 6). ).

  The operation of the flow setting processing unit 340 is an operation for broadcasting the packet to all the GWSs when the destination address of the packet is not stored in the station information management unit 405 when the packet is received from the GWS. Can be said.

  The OFS 400 outputs a packet from the port #Z of the OFS 400 based on the “packet out” message (step S5 shown in FIG. 6). As a result, the DNS server 30 receives from the OFS 400 a packet whose source is the PC 11a.

  When the DNS server 30 receives a packet whose source is the PC 11a, the DNS server 30 transmits, as a response to the PC 11a, a packet whose source is the DNS server 30 and whose destination is the PC 11a to the OFS 400 (step S6 shown in FIG. 6).

  It is assumed that a flow entry corresponding to this packet has not been set in the OFS 400 yet. In this case, the OFS 400 transmits the packet together with the “packet in” message to the switch control device 700 (step S7 shown in FIG. 6). At this time, the OFS 400 also transmits station information regarding the DNS server 30 and the OFS 400 to the switch control device 700.

  Upon receiving the packet and station information, the flow setting processing unit 340 of the switch control device 700 creates a flow entry to be set in the OFS 400 that has transmitted the “packet in” message, and sets the flow entry in the OFS 400 ( Step S8 shown in FIG. FIG. 8 is an explanatory diagram showing an example of a flow entry set in the OFS 400 in step S8.

  The flow setting processing unit 340 recognizes from the station information received from the OFS 400 that the DNS server 30 that is the terminal of the packet transmission source is connected to the port #Z of the OFS 400. Based on the station information, the flow setting processing unit 340 sends to the OFS 400 a flow entry that specifies that a packet destined for the terminal of the packet transmission source (DNS server 30 in this example) is transferred to the terminal. Set. The first flow entry shown in FIG. 8 is this flow entry. The first flow entry shown in FIG. 8 outputs a packet in which the destination MAC address and the destination IP address match the MAC address and IP address of the DNS server 30 from the port #Z (that is, forwards to the DNS server 30). Is stipulated.

  Further, the flow setting processing unit 340 forwards, to the OFS 400, packets whose destination address corresponds to the address of the subnetwork corresponding to the GWS to the relay switch for each GWS other than the OFS 400. Set the flow entry that stipulates to do. The three flow entries from the second to the fourth shown in FIG. 8 are this flow entry. For example, in the second flow entry shown in FIG. 8, the source MAC address is the MAC address of the DNS server 30, and the destination IP address is the address of the subnetwork corresponding to the OFS 100 (“192.168.0.0/26”). It stipulates that the corresponding packet is output from port # 1 (that is, transferred to the relay switch). The third and fourth flow entries shown in FIG. 8 are similar flow entries corresponding to the OFSs 200 and 300.

  Further, the station information reception unit 390 of the switch control device 700 stores the station information received from the OFS 400 in the station information management unit 405.

  After step S8, the flow setting processing unit 340 determines which port of which GWS the terminal having the destination MAC address of the packet received together with the “packet in” message (here, the PC 11a) is connected to which station information. Inspection is performed based on the station information 410 stored in the management unit 405. Station information indicating that the PC 11a is connected to the port #X of the OFS 100 is already stored in the station information management unit 405. Accordingly, the flow setting processing unit 340 recognizes that the terminal (PC 11a) having the packet destination MAC address is connected to the port #X of the OFS 100. Then, the flow setting processing unit 340 sends the packet received from the OFS 400 in step S7 and a “packet out” message indicating that the packet is output from the port #X to the OFS 100 (the terminal having the destination MAC address of the packet). To the connected GWS) (step S9 shown in FIG. 5).

  The OFS 100 outputs a packet from the port #X of the OFS 100 based on the “packet out” message (step S10 shown in FIG. 5). As a result, the PC 11a receives from the OFS 100 a packet whose source is the DNS server 30.

  After the processing of steps S1 to S10, the flow entry set in the GWS (OFS 100, 400) in the process of steps S1 to S10 and the flow entry set in the relay switch (OFS 500) in the preliminary preparation stage, The GWS can transfer packets transmitted and received between the PC 11a and the DNS server 30.

  For example, it is assumed that the OFS 100 receives a packet addressed to the DNS server 30 from the PC 11a. The destination IP address (IP address of the DNS server 30) of this packet corresponds to the IP address (“192.168.0.192/26”) of the subnetwork corresponding to the OFS 400. Accordingly, the OFS 100 outputs a packet from the port # 1 according to the fourth flow entry shown in FIG. When the relay switch (OFS 500) receives this packet, it outputs the packet from the port # 4 according to the flow entry (specifically, the fourth flow entry shown in FIG. 4) set in the OFS 500 in the preparation stage. To do. When receiving this packet, the OFS 400 outputs the packet from the port #Z according to the first flow entry shown in FIG. As a result, the packet reaches the DNS server 30.

  For example, it is assumed that the OFS 400 receives a packet addressed to the PC 11a from the DNS server 30. The destination IP address of this packet (the IP address of the PC 11a) corresponds to the IP address (“192.168.0.0/26”) of the subnetwork corresponding to the OFS 100. Therefore, the OFS 400 outputs a packet from the port # 1 according to the second flow entry shown in FIG. When receiving this packet, the relay switch (OFS 500) outputs the packet from the port # 1 according to the flow entry (specifically, the first flow entry shown in FIG. 4) set in the OFS 500 in the stage of preparation. To do. When receiving this packet, the OFS 100 outputs the packet from the port #X according to the first flow entry shown in FIG. As a result, the packet reaches the PC 11a.

  Next, a case where the address of the terminal that performs communication does not correspond to the address of the subnetwork corresponding to the GWS connected to the terminal will be described.

  FIG. 9, FIG. 10 and FIG. 11 are explanatory diagrams showing examples of processing progress when the address of a terminal that performs communication does not correspond to the address of a subnetwork corresponding to the GWS connected to the terminal. 9, FIG. 10 and FIG. 11 are diagrams in which a part of FIG. 1 is extracted and step numbers are added.

  Here, description will be made assuming that the IP address of the PC 11b does not correspond to the IP address of the subnetwork corresponding to the GWS (OFS 100) to which the PC 11b is connected. Further, it is assumed that the IP address of the PC 11b corresponds to the IP address of the subnetwork corresponding to the OFS 200. Note that the IP address of the DNS server 30 corresponds to the subnetwork IP address corresponding to the GWS (OFS 400) to which the DNS server 30 is connected, as in the above case.

  First, the PC 11b transmits a packet addressed to the PC 11b and addressed to the DNS server 30 to the OFS 100 (step T1 shown in FIG. 9).

  It is assumed that the flow entry corresponding to this packet has not been set in the OFS 100 yet. In this case, the OFS 100 transmits the packet together with the “packet in” message to the switch control device 700 (step T2 shown in FIG. 9). At this time, the OFS 100 also transmits station information regarding the PC 11b and the OFS 100 to the switch control device 700.

  Upon receiving the packet and station information, the flow setting processing unit 340 of the switch control device 700 creates a flow entry to be set in the OFS 100 that has transmitted the “packet in” message, and sets the flow entry in the OFS 100 ( Step T3a) shown in FIG. FIG. 12 is an explanatory diagram illustrating an example of a flow entry set in the OFS 100 in step T3a.

  From the station information received from the OFS 100, the flow setting processing unit 340 recognizes that the PC 11b that is the packet transmission source terminal is connected to the port #Y of the OFS 100. Based on the station information, the flow setting processing unit 340 sets, in the OFS 100, a flow entry that stipulates that a packet destined for the packet transmission source terminal (PC 11b in this example) is transferred to the terminal. . The first flow shown in FIG. 12 is this flow entry. The first flow entry shown in FIG. 12 specifies that a packet whose destination MAC address and destination IP address match the MAC address and IP address of PC 11b is output from port #Y (that is, transferred to PC 11b). Yes.

  Further, the flow setting processing unit 340 forwards, to the OFS 100, a packet whose destination is the address of the subnetwork corresponding to the GWS and the destination address for each GWS other than the OFS 100 to the relay switch. Set the flow entry that stipulates to do. The three flow entries from the second to the fourth shown in FIG. 12 are this flow entry. For example, in the second flow entry shown in FIG. 12, the source MAC address is the MAC address of the PC 11b, and the destination IP address corresponds to the address of the subnetwork corresponding to the OFS 200 (“192.168.0.64/26”). It defines that a packet is output from port # 1 (that is, transferred to a relay switch). The third and fourth flow entries shown in FIG. 12 are similar flow entries corresponding to the OFSs 300 and 400.

Further, the station information reception unit 390 of the switch control device 700 stores the station information received from the OFS 100 in the station information management unit 405.

  The flow setting processing unit 340 refers to the transmission source IP address of the packet received from the OFS 100 in step T2, and the transmission source IP address (the IP address of the PC 11b) corresponds to the OFS 100 that transmitted the packet in step T2. Recognize that it does not correspond to the subnetwork address ("192.168.0.0/26"). In this case, for the GWS corresponding to the subnetwork to which the source IP address of the packet corresponds, the flow setting processing unit 340 sets the source address of the packet to the GWS (OFS 100) that transmitted the packet in Step T2. A flow entry that defines the transfer of the destination packet is set (step T3b shown in FIG. 10). In Step T3b, first, the flow setting processing unit 340 specifies the GWS corresponding to the subnetwork to which the transmission source IP address of the packet corresponds based on the GWS information 420. Here, the source IP address of the packet is the IP address of the PC 11b. The IP address of the PC 11b corresponds to the IP address of the subnetwork corresponding to the OFS 200. Therefore, the flow setting processing unit 340 identifies the OFS 200 as the GWS corresponding to the subnetwork to which the transmission source IP address of the packet corresponds. Then, the flow setting processing unit 340 sets, for the OFS 200, a flow entry that specifies that the packet whose destination address is the source address of the packet is transferred to the GWS (OFS 100) that transmitted the packet in step T2. .

  FIG. 13 is an explanatory diagram showing an example of a flow entry set in the OFS 200 in step T3b. The flow entry shown in FIG. 13 is a packet whose destination MAC address and destination IP address match the source MAC address and source IP address of the packet received from the OFS 100 in step T2 (that is, the MAC address and IP address of the PC 11b). Is output from the port #W (that is, transferred to the OFS 100).

  After step T3b, the flow setting processing unit 340 stores in the station information management unit 405 which port of which GWS the terminal having the destination MAC address of the packet received together with the “packet in” message is connected. The inspection is performed based on the station information 410 being present. However, here, the terminal (DNS server 30) having the packet destination MAC address does not transmit the station information to the switch control device 700. For this reason, the flow setting processing unit 340 cannot identify which port of which GWS the terminal having the destination MAC address of the packet received together with the “packet in” message is connected. In this case, the flow setting processing unit 340 transmits the packet received from the OFS 100 in step T2 and the “packet out” message indicating that the packet is broadcasted to all GWSs (step T4 shown in FIG. 11). ).

  The operation in step T4 is the same as that in step S4. When a packet is received from the GWS, if the destination address of the packet is not stored in the station information management unit 405, the packet is broadcast to all the GWSs. It can be said that this is an operation to transmit.

  The OFS 400 outputs a packet from the port #Z of the OFS 400 based on the “packet out” message (step T5 shown in FIG. 11). As a result, the DNS server 30 receives from the OFS 400 a packet whose source is the PC 11b.

  When the DNS server 30 receives a packet whose source is the PC 11b, the DNS server 30 transmits, as a response to the PC 11b, a packet whose source is the DNS server 30 and whose destination is the PC 11b to the OFS 400 (step T6 shown in FIG. 11).

  It is assumed that a flow entry corresponding to this packet has not been set in the OFS 400 yet. In this case, the OFS 400 transmits the packet together with the “packet in” message to the switch control device 700 (step T7 shown in FIG. 11). At this time, the OFS 400 also transmits station information regarding the DNS server 30 and the OFS 400 to the switch control device 700.

  Upon receiving the packet and station information, the flow setting processing unit 340 of the switch control device 700 creates a flow entry to be set in the OFS 400 that has transmitted the “packet in” message, and sets the flow entry in the OFS 400 ( Step T8 shown in FIG. FIG. 14 is an explanatory diagram showing an example of a flow entry set in the OFS 400 in step T8.

  The flow setting processing unit 340 recognizes from the station information received from the OFS 400 that the DNS server 30 that is the terminal of the packet transmission source is connected to the port #Z of the OFS 400. Based on the station information, the flow setting processing unit 340 sends to the OFS 400 a flow entry that specifies that a packet destined for the terminal of the packet transmission source (DNS server 30 in this example) is transferred to the terminal. Set. The first flow entry shown in FIG. 14 is this flow entry. The first flow entry shown in FIG. 14 outputs a packet whose destination MAC address and destination IP address match the MAC address and IP address of the DNS server 30 from the port #Z (that is, forwards it to the DNS server 30). Is stipulated.

  Further, the flow setting processing unit 340 forwards, to the OFS 400, packets whose destination address corresponds to the address of the subnetwork corresponding to the GWS to the relay switch for each GWS other than the OFS 400. Set the flow entry that stipulates to do. The three flow entries from the second to the fourth shown in FIG. 14 are the flow entries. For example, in the second flow entry shown in FIG. 14, the source MAC address is the MAC address of the DNS server 30, and the destination IP address is the address of the subnetwork corresponding to the OFS 100 (“192.168.0.0/26”). It stipulates that the corresponding packet is output from port # 1 (that is, transferred to the relay switch). The third and fourth flow entries shown in FIG. 14 are similar flow entries corresponding to the OFSs 200 and 300.

  Further, the station information reception unit 390 of the switch control device 700 stores the station information received from the OFS 400 in the station information management unit 405.

  The operation of step T8 is the same as the operation of step S8 described above, and the flow entry shown in FIG. 14 is the same flow entry as the flow entry shown in FIG.

  After step T8, the flow setting processing unit 340 determines which port of which GWS the terminal having the destination MAC address of the packet received together with the “packet in” message (here, the PC 11b) is connected to which station information. Inspection is performed based on the station information 410 stored in the management unit 405. Station information indicating that the PC 11b is connected to the port #Y of the OFS 100 is already stored in the station information management unit 405. Therefore, the flow setting processing unit 340 recognizes that the terminal (PC 11b) having the packet destination MAC address is connected to the port #Y of the OFS 100. Then, the flow setting processing unit 340 sends the packet received from the OFS 400 in step T7 and a “packet out” message indicating that the packet is output from the port #Y to the OFS 100 (the terminal having the destination MAC address of the packet). To the connected GWS) (step T9 shown in FIG. 9).

  The OFS 100 outputs a packet from the port #Y of the OFS 100 based on the “packet out” message (step T10 shown in FIG. 9). As a result, the PC 11b receives from the OFS 100 a packet whose source is the DNS server 30.

  After the processing of steps T1 to T10, the flow entry set in the GWS (OFS 100, 200, 400) in the process of steps T1 to T10, and the flow entry set in the relay switch (OFS 500) in the preparatory stage As a result, the GWS can transfer packets transmitted and received between the PC 11b and the DNS server 30.

  For example, it is assumed that the OFS 100 receives a packet addressed to the DNS server 30 from the PC 11b. The destination IP address (IP address of the DNS server 30) of this packet corresponds to the IP address (“192.168.0.192/26”) of the subnetwork corresponding to the OFS 400. Accordingly, the OFS 100 outputs a packet from the port # 1 in accordance with the fourth flow entry shown in FIG. When the relay switch (OFS 500) receives this packet, it outputs the packet from the port # 4 according to the flow entry (specifically, the fourth flow entry shown in FIG. 4) set in the OFS 500 in the preparation stage. To do. When receiving this packet, the OFS 400 outputs the packet from the port #Z according to the first flow entry shown in FIG. As a result, the packet reaches the DNS server 30.

  For example, it is assumed that the OFS 400 receives a packet addressed to the PC 11b from the DNS server 30. The destination IP address of this packet (the IP address of the PC 11b) corresponds to the IP address (“192.168.0.64/26”) of the subnetwork corresponding to the OFS 200. Accordingly, the OFS 400 outputs a packet from the port # 1 according to the third flow entry shown in FIG. When the relay switch (OFS 500) receives this packet, it outputs the packet from the port # 2 according to the flow entry (specifically, the second flow entry shown in FIG. 4) set in the OFS 500 in the preparation stage. To do. When receiving this packet, the OFS 200 outputs the packet from the port #W according to the flow entry shown in FIG. As a result, the OFS 110 receives a packet from the OFS 200 without passing through the OFS 500. Then, the OFS 100 outputs a packet from the port #Y according to the first flow entry shown in FIG. As a result, the packet arrives at the PC 11b.

  Next, the effect of the present invention will be described.

  First, the number of flow entries set in one GWS in the present invention will be described. The number of flow entries that are set in one GWS and that specify that a packet is transferred to the relay switch is expressed by the following equation (1).

  Number of terminals connected to GWS × (Number of GWS−1) (1)

  In addition, the number of flow entries that are set in one GWS and specify that a packet is transferred to a terminal is the number of terminals that are connected to the GWS.

  Therefore, the number of flow entries set in one GWS is the sum of “number of terminals connected to GWS × (number of GWS−1)” and “number of terminals connected to GWS”. It is represented by the following formula (2).

  Number of terminals connected to GWS x number of GWS (2)

  Next, the number of flow entries set in one OFS in a general technique will be described. In the general technique, the number of flow entries that are set in one OFS and specify that the packet is transferred to the relay switch is expressed by the following equation (3).

  Number of terminals connected to OFS x number of destination terminals (3)

  In addition, the number of flow entries that are set in one OFS in a general technique and specify that a packet is transferred to a terminal is the number of terminals that are connected to the OFS.

  Therefore, in general technology, the number of flow entries set in one OFS is “the number of terminals connected to OFS × the number of terminals serving as destinations” and “the number of terminals connected to OFS”. And is represented by the following formula (4).

  Number of terminals connected to OFS × (number of destination terminals + 1) (4)

  The ratio of the number of flow entries set in one OFS in the present invention to the number of flow entries set in one OFS in a general technique is expressed by the following equation (5).

  Since “the number of terminals connected to the GWS” = “the number of terminals connected to the OFS”, Expression (5) is expressed by Expression (6) below.

  Number of GWS / (Number of destination terminals + 1) (6)

  Here, the number of GWS is about several to several tens, for example. Further, the number of terminals serving as destinations is, for example, several tens to several hundreds. Therefore, according to the present invention, the number of flow entries set in one GWS can be suppressed to about 1/10 to 1/100 of the number of flow entries set in one OFS in a general technique. it can.

  Therefore, according to the present invention, an increase in the number of flow entries set in an OFS can be prevented even when access is concentrated on terminals connected to the OFS.

  Next, the outline of the present invention will be described. FIG. 15 is a block diagram showing an outline of the switch control device of the present invention. The switch control device 51 is a flow entry setting unit 52 that sets a flow entry that defines an action for a packet for a gateway switch that is a switch associated with the subnetwork and a relay switch that relays the packet between the gateway switches. (For example, a flow setting processing unit 340).

  The flow entry setting means 52 sends a flow entry that specifies that a packet whose destination address corresponds to the address of the subnetwork corresponding to the gateway switch to the gateway switch is transferred to the gateway switch. Set for each gateway switch.

  Further, the flow entry setting means 52, when receiving a packet from the gateway switch, sends a flow entry that specifies that the packet destined for the terminal of the packet transmission source is transferred to the gateway switch. Set. Further, the flow entry setting means 52 uses the terminal as the transmission source for each gateway switch other than the gateway switch, and the destination address corresponds to the address of the subnetwork corresponding to the gateway switch. Set the flow entry that specifies that the packet is forwarded to the relay switch.

  With such a configuration, it is possible to prevent an increase in the number of flow entries set in the switch even when access is concentrated on terminals connected to the switch.

  When the flow entry setting means 52 receives a packet from a gateway switch, if the packet source address does not correspond to the address of the subnetwork corresponding to the gateway switch, the subnetwork corresponding to the packet source address For the gateway switch corresponding to the above, a configuration may be used in which a flow entry that defines that a packet destined for the source address of the packet is transferred to the gateway switch that transmitted the packet is set.

Terminal address storage means (for example, station information management unit 405) for storing the address of the terminal connected to the gateway switch,
The flow entry setting means 52
When a packet is received from the gateway switch, if the destination address of the packet is not stored in the terminal address storage unit, the configuration may be such that all the gateway switches broadcast the packet.

  The present invention is preferably applied to a switch control device that controls a switch that transfers a packet.

100, 200, 300, 400, 500 OFS
305 Communication processing unit 310 Configuration setting unit 320 Configuration information management unit 340 Flow setting processing unit 350 Route calculation processing unit 360 Topology information reception unit 370 Topology information management unit 390 Station information reception unit 405 Station information management unit 430 GWS management unit

Claims (9)

A flow entry setting means for setting a flow entry that defines an action for a packet for a gateway switch that is a switch associated with the sub-network and a relay switch that relays the packet between the gateway switches;
The flow entry setting means includes:
For each relay switch other than the relay switch, a flow entry that specifies that a packet whose destination address corresponds to the address of the subnetwork corresponding to the gateway switch is transferred to the relay switch. And
When a packet is received from the gateway switch, a flow entry is set for the gateway switch that specifies that the packet destined for the terminal of the packet transmission source is forwarded to the terminal. On the other hand, for each gateway switch other than the gateway switch, a flow specifying that the terminal is a transmission source and that a packet whose destination address corresponds to the address of the subnetwork corresponding to the gateway switch is transferred to the relay switch A switch control device characterized by setting an entry. Flow entry setting means
When the packet is received from the gateway switch, if the source address of the packet does not correspond to the address of the subnetwork corresponding to the gateway switch, the gateway switch corresponding to the subnetwork corresponding to the source address of the packet The switch control device according to claim 1, wherein a flow entry that specifies forwarding of a packet whose destination is the source address of the packet is set to the gateway switch that has transmitted the packet. Terminal address storage means for storing the address of the terminal connected to the gateway switch,
Flow entry setting means
The switch according to claim 1 or 2, wherein, when a packet is received from a gateway switch, if the destination address of the packet is not stored in the terminal address storage unit, the packet is transmitted to all gateway switches by broadcast. Control device. A switch control device for controlling the switch
For a relay switch that relays packets between gateway switches that are switches associated with a subnetwork, a packet whose destination address corresponds to the address of the subnetwork corresponding to the gateway switch is transferred to the gateway switch. Is set for each gateway switch other than the relay switch,
When a packet is received from the gateway switch, a flow entry is set for the gateway switch that specifies that the packet destined for the terminal of the packet transmission source is forwarded to the terminal. On the other hand, for each gateway switch other than the gateway switch, a flow specifying that the terminal is a transmission source and that a packet whose destination address corresponds to the address of the subnetwork corresponding to the gateway switch is transferred to the relay switch A switch control method characterized by setting an entry. The switch controller
When the packet is received from the gateway switch, if the source address of the packet does not correspond to the address of the subnetwork corresponding to the gateway switch, the gateway switch corresponding to the subnetwork corresponding to the source address of the packet The switch control method according to claim 4, wherein a flow entry specifying that a packet whose destination is a source address of the packet is transferred to the gateway switch that has transmitted the packet is set. The switch controller
Store the address of the terminal connected to the gateway switch in the terminal address storage means,
The switch according to claim 4 or 5, wherein when a packet is received from a gateway switch, if the destination address of the packet is not stored in the terminal address storage means, all the gateway switches are broadcasted. Control method. A switch control program mounted on a computer for controlling a switch,
In the computer,
For a relay switch that relays packets between gateway switches that are switches associated with a subnetwork, a packet whose destination address corresponds to the address of the subnetwork corresponding to the gateway switch is transferred to the gateway switch. Processing for setting the flow entry for each gateway switch other than the relay switch, and
When a packet is received from the gateway switch, a flow entry is set for the gateway switch that specifies that the packet destined for the terminal of the packet transmission source is forwarded to the terminal. On the other hand, for each gateway switch other than the gateway switch, a flow specifying that the terminal is a transmission source and that a packet whose destination address corresponds to the address of the subnetwork corresponding to the gateway switch is transferred to the relay switch A switch control program for executing the process of setting entries. On the computer,
When the packet is received from the gateway switch, if the source address of the packet does not correspond to the address of the subnetwork corresponding to the gateway switch, the gateway switch corresponding to the subnetwork corresponding to the source address of the packet The switch control program according to claim 7, wherein a processing is performed to set a flow entry that defines that a packet whose destination is the source address of the packet is transferred to the gateway switch that has transmitted the packet. On the computer,
Processing for storing the address of the terminal connected to the gateway switch in the terminal address storage means; and
9. When a packet is received from a gateway switch, if the destination address of the packet is not stored in the terminal address storage means, a process for broadcasting the packet to all gateway switches is executed. Switch control program described in 1.

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