JP2009267917A - Packet transfer apparatus and packet transfer method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a packet transfer apparatus which transmits a PADI packet only to a GW device which sets Service Name that a user has designated, and transmits a PADO packet only to a PADO packet waiting terminal. <P>SOLUTION: In a packet transfer apparatus, correspondence between Service Name and a GW device, to which the Service Name is registered, is set to a management table, beforehand. When a PADI packet is received from a terminal, the packet transfer apparatus determines the presence or the absence of Service Name, transfers the PADI packet to each of corresponding GW devices in the management table, and registers on a PADO wait management table. When a PADO packet is received from a GW device and there is an entry on the PADO wait management table, the PADO packet is transferred to the terminal, and clearing of the entry on the PADO wait management table is carried out. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a packet transfer apparatus and a packet transfer method, and more particularly to a packet transfer apparatus and a packet transfer method for connecting a terminal to a connection destination communication network using PPPoE.

  A communication network (IP network) using IP (Internet Protocol) has become widespread, and various communication services such as WEB access, file transfer, VoIP (Voice over IP), and multicast have been provided. It was. As a communication system that provides such a communication service, a gateway (GW) device that appropriately performs communication processing on a received IP packet and forwards it, and a network (access network: communication carrier) that accommodates a user terminal that enjoys the communication service. Provided) and a network providing communication services (ISP (Internet Service Provider for each communication service, managed / provided by a communication carrier)), and a communication system configured to transfer packets from a terminal to ISP equipment Widely adopted.

  In an access network, in order to ensure the safety and reliability of a packet to be transmitted and received, a packet is established by establishing a PPP session between a user terminal and a GW apparatus using a protocol called PPP over Ethernet (registered trademark). A configuration for packet transfer using PPPoE (Point to point protocol over Ethernet: defined in Non-Patent Document 1) for transferring a packet has been widely adopted.

  PPPoE is a protocol that establishes a PPP session between a GW device on Ethernet and a terminal on the user side (access network), and transfers packets as if using a dedicated line.

  The PPPoE sequence starts by broadcasting a start packet called a PADI (The PPPoE Active Discovery Initiation) packet to the GW apparatus in order to search for a packet transfer apparatus that provides a desired communication service from the terminal side. The GW apparatus that can support the requested communication service (packet transfer to the communication service provider's equipment) returns a PADO (The PPPoE Active Discovery Offer) packet to the terminal. Next, the terminal transmits a PADR (The PPPoE Active Discovery Request) packet for requesting the start of the PPP session to the identified GW device. The corresponding GW apparatus assigns a unique session ID to the terminal and returns a confirmation packet called PADS (The PPPoE Active Discovery Session-Confirmation). With these sequences, a PPP session is established. After the PPP session is established, packet transfer using PPP is executed using the session ID.

  In the above-described sequence, the user designates Service Name and transmits a PADI packet by broadcast. The GW apparatus in which the corresponding Service Name is set returns a PADO packet. However, the GW device for which Service Name is not set also returns a PADO packet.

  In a communication system that performs communication using PPPoE, the terminal side can specify a Service Name indicating the type of communication service to be requested and a TAG length indicating the length of the Service Name in the PADI packet. When the Service Name is not specified in the PADI packet parameter, the GW apparatus regards the TAG length of the Service Name as 0. A PADI packet with a Service Name TAG length of 0 indicates that any service can be accepted, and the PADI packet is transferred to all GW devices. As a result, all the GW apparatuses that have received the PADI packet transmit the PADO packet to the terminal.

  By setting Service Name in the GW device in advance, the PADO packet is transmitted to the terminal only from the GW device desired by the terminal by specifying the Service Name or TAG length in the PADI packet. . GW apparatuses with different Service Names do not transmit PADO packets to terminals. However, even in the GW apparatus in which the Service Name is set, if a PADI packet in which the Service Name is not set is received from the terminal, the PADO packet is transmitted to the terminal.

  As a means for solving this problem, Patent Document 2 discloses that when Service Name is set in the GW device, when a PADI packet in which Service Name is not set is received, a PADO packet is not transmitted to the terminal. Is described. However, even in this case, the GW apparatus places a load on the CPU due to the PADI packet determination process.

  In Patent Document 1, one GW device is selected as a packet transfer device, and a PADI packet is transferred only to the selected GW device, whereby load distribution of each GW device is performed. However, even in this case, the GW device is selected according to the load information notified by the PADO packet from each GW device without identifying the Service Name of the PADI packet. In addition, the PADI packet must be transferred by converting the broadcast MAC address to the unicast MAC address for the selected GW device.

  Further, Patent Document 3 transfers a PADI packet in a packet transfer device, selects one PADO packet from PADO packets received from each GW device, and transfers the selected PADO packet to a terminal. As a result, the load distribution control of the GW apparatus can be performed in the packet transfer apparatus, and the load of the PADO packet reception process in the terminal is reduced. However, there is no description of recognizing the Service Name of the PADI packet and transferring the PADI packet to the GW device.

Japanese Patent Application Laid-Open No. 2004-158977 JP 2006-191541 A JP 2007-208352 A RFC2516

  An object of the present invention is to control network traffic. Specifically, in a packet transfer device installed between a terminal and a plurality of GW devices, when receiving a PADI packet from the terminal, the service name is identified, and the GW device in which the service name is registered in advance is identified. A function to transfer the PADI packet only. This reduces the PADI packet reception processing of the GW device. Furthermore, in consideration of load distribution from PADO packets from a plurality of GW apparatuses, one PADO packet is selected, and the selected PADO packet is transferred to the terminal. This reduces the PADO packet reception process of the terminal. Furthermore, load distribution control of a plurality of GW apparatuses is performed in the packet transfer apparatus.

  In order to solve the above problems, a packet transfer apparatus according to the present invention controls a packet transfer between a plurality of line interfaces accommodating a connection line with a terminal and a connection line with a GW apparatus, and communication between the line interfaces. An internal switch, a control processor, and a memory are provided for transferring a PADI packet to a plurality of redundant GW devices when a PADI packet to a network providing a service is received. The memory includes various management tables for storing transfer control information of communication control packets for each user terminal, and a plurality of the above-mentioned plurality of the same PADI packets based on the transfer information indicated by the management table and the port management table for managing the load. One of the PADO packets returned from the GW apparatus is selectively transferred to the requesting user terminal, and the other PADO packets are discarded.

  Here, when the user terminal is a PPPoE terminal, the connection start request packet is a PADI packet, the response packet from the GW apparatus is a PADO packet, and the packet transfer apparatus selectively transfers the PADO packet to the PPPoE terminal. The PPPoE packet is transferred between the user terminal and the selected GW device.

  By specifying the Service Name or TAG length in the PADI packet that is issued when the terminal requests connection, the PADI packet is issued only to the GW device desired by the terminal. In addition, the packet transfer apparatus is set in advance so that all PADO packets (connection response packets) are not returned to the terminal in response to the PADI packet (connection request packet) issued by the terminal. As a result, the transfer efficiency of the GW device is reduced and the load on the CPU is reduced. Further, when the packet transfer apparatus accepts a plurality of PADO packets, it has a function of determining a connection destination in consideration of first-come-first-served basis or load distribution.

  In the packet transfer apparatus, the internal switch transfers the communication control packet received from each line interface to the control processor, and selects either the communication control packet received from the control processor or the user packet received from each line interface according to the respective header information. To the line interface. However, the internal switch may transfer only the PADO packets specified in the above-described various management tables among the PADO packets received from each line interface to the control processor.

  The above-described problems include a plurality of line interfaces, internal switches connected to these line interfaces, transmission buffers and reception buffers connected to the internal switches, and control processors that control the internal switches, transmission buffers, and reception buffers. And a memory that holds the program of the control processor, and the memory holds a service management table that associates the line interface numbers corresponding to the plurality of connected gateway devices with the services of the gateway devices. When a connection request packet specifying a service is received from a terminal, a packet transfer device that refers to a service management table, specifies a destination gateway device of the connection request packet, and transfers the connection request packet to the specified gateway device Can be achieved.

  A plurality of line interfaces; internal switches connected to the line interfaces; transmission buffers and reception buffers connected to the internal switches; a control processor that controls the internal switches, transmission buffers, and reception buffers; and A memory for holding a program of the control processor, a step of holding a service management table for associating line interface numbers corresponding to a plurality of gateway devices connected to the memory and services of the gateway device, and from a connected terminal Receiving a connection request packet specifying a service, referring to a service management table, specifying a destination gateway device of the connection request packet, and transferring the connection request packet to the specified gateway device The packet transfer method comprising, can be achieved.

  Note that the packet transfer apparatus of the present specification has a line interface having a function of a station side device (OLT: Optical Line Terminal) of a metal line interface, an optical line interface, or a passive optical network PON (Passive Optical Network) as a line interface. By applying, L2SW and OLT are included.

  ADVANTAGE OF THE INVENTION According to this invention, in the communication system which communicates using PPPoE, the packet transfer apparatus which requests a connection only to the communication network which a terminal requests | requires can be provided. Furthermore, if the load distribution function at the time of session establishment is selected, access is not concentrated on a specific GW device.

  Embodiments of the present invention will be described below with reference to the drawings using examples. The same reference numerals are assigned to substantially the same parts, and the description will not be repeated.

  A first embodiment will be described with reference to FIGS. Here, FIG. 1 and FIG. 2 are block diagrams of the communication system. FIG. 3 is a block diagram of the packet transfer apparatus. FIG. 4 is a diagram for explaining the format of the PADI packet. FIG. 5 is a diagram for explaining a TAG format. FIG. 6 is a diagram for explaining the Service Name management table. FIG. 7 is a diagram for explaining the port management table. FIG. 8 is a diagram for explaining the PADO waiting management table. FIG. 9 is a sequence diagram among a terminal, a packet transfer apparatus, and two GWs. FIG. 10 is a flowchart of PADI reception by the packet transfer apparatus. FIG. 11 is a flowchart of PADO reception of the packet transfer apparatus.

  In FIG. 1, the communication network 100 includes an access network 1, the Internet 2, a VoIP network 3, and a plurality of GW devices 20 that connect the access network 1 and the Internet 2 or VoIP network 3.

  The Internet 2 includes a layer 2 SW (L2 SW) 30-1 and a WEB server 40. The VoIP network 3 includes a layer 2 SW 30-2 and a SIP (Session Initiation protocol) server 50. The access network 1 is connected to terminals 60-5 and 60-6 via a packet transfer apparatus 10-1 connected to the terminals 60-1 to 60-4, a star coupler 90, and an ONU (Optical Network Unit) 80. And the packet transfer apparatus 10-2 directly connected to the terminal 60-7.

  The access network 1 is connected to the Internet 2 via GW apparatuses 20-1 and 20-2 having a communication frame termination function based on different protocols of IEEE802.1X and PPPoE. The access network 1 is also connected to the VoIP network 3 via the GW devices 20-3 and 20-4.

  Each terminal 60 has a session connection function based on IEEE802.1X or PPPoE. The packet transfer apparatus 10 is connected to a plurality of redundant GW apparatuses 20-1 to 20-4.

  The packet transfer apparatus 10 is used for selectively connecting one of a plurality of redundant GW apparatuses 20 to the terminal 60 in addition to a general L2SW function for transferring a received packet according to layer 2 header information. A GW device selection function is provided.

  The packet transfer apparatus 10-1 accommodates the terminals 60-1 to 60-4 via individual access lines. On the other hand, the packet transfer apparatus 10-2 accommodates terminals 60-5 to 60-6 via a passive optical network PON (Passive Optical Network). The PON includes subscriber connection devices (ONUs) 80-1 and 80-2, a station side device OLT (Optical Line Terminal) (not shown) built in the packet transfer device 10-2, and one light accommodated in the OLT. The optical fiber network has a structure in which a fiber is branched into a plurality of branch optical fibers by a star coupler (SC) 90.

  With reference to FIG. 2, the GW apparatus selection function with which a packet transfer apparatus is provided is demonstrated. Although described here as the packet transfer apparatus 10-1, the packet transfer apparatus 10-2 in FIG. 1 also has a GW apparatus selection function similar to that of the packet transfer apparatus 10-1.

  In FIG. 2, a communication network 100A includes an access network 1, an Internet 2, a VoIP network 3, n GW devices 20I-1 to 20I-n that connect the access network 1 and the Internet 2, and an access network 1 And m GW devices 20V-1 to 20V-m that connect the VoIP network 3.

  A WEB server 40 exists in the Internet 2 and is connected to the GW apparatuses 20I-1 to 20I-n. The VoIP network 3 includes a SIP server and is connected to the GW devices 20V-1 to 20V-m. The access network 1 includes a packet transfer apparatus 10-1, which is connected to the terminals 60-1 to 60-4. Here, it is assumed that the terminals 60-1 and 60-2 use the WEB reference service, and the terminals 60-3 and 60-4 use the VoIP service.

  A terminal 60-1 is connected to port 1 of the packet transfer apparatus 10-1. Similarly, terminals 60-2 to 60-4 are connected to the ports 2 to 4, respectively. Furthermore, GW apparatuses 20I-1 to 20I-n are connected to the ports 5 to 4 + n. GW devices 20V-1 to 20V-m are connected to the ports 5 + n to 4 + n + m.

  Each of the terminal 60 and the GW apparatus 20 holds an attached MAC address. In the GW apparatuses 20I-1 to 20I-n, WEB is set as the Service Name. In the GW devices 20V-1 to 20V-m, VoIP is set as the Service Name.

  Here, the operation when the packet transfer apparatus 10-1 receives a session connection request from the terminals 60-1 to 60-4 executing the session connection procedure according to PPPoE will be described.

  When the packet transfer apparatus 10-1 receives a PPPoE PADI packet (Service Name: WEB) from the terminal 60-1, the packet transfer apparatus 10-1 transmits a PADI packet to the GW apparatuses 20I-1 to 20I-n connected to the packet transfer apparatus 10-1. Forward. The packet transfer apparatus 10-1 monitors the connection control procedure of the GW apparatuses 20I-1 to 20I-n. When the PADO packet corresponding to the connection request is received from the GW apparatuses 20I-1 to 20I-n, the packet transfer apparatus 10-1 selects one of the GW apparatuses, here the GW apparatus 20I-1, and then connects Continue the control procedure. After selecting the GW device 20I-1, the packet transfer device 10-1 does not transfer packets from the other GW devices 20I-2 to 20I-n to the PPPoE terminal 60-1. Thereafter, the PPPoE terminal 60-1 communicates with the Internet 2 via the selected GW apparatus 20I-1 (thick solid line in FIG. 2).

  When the packet transfer apparatus 10-1 receives a PPPoE PADI packet (Service Name: VoIP) from the terminal 60-3, the packet transfer apparatus 10-1 transmits the PADI packet to the GW apparatuses 20V-1 to 20V-m connected to the packet transfer apparatus 10-1. Forward. The packet transfer apparatus 10-1 monitors the connection control procedure of the GW apparatuses 20V-1 to 20V-m. When the PADO packet corresponding to the connection request is received from the GW devices 20V-1 to 20V-m, the packet transfer device 10-1 selects one of the GW devices, here the GW device 20V-1, and then connects Continue the control procedure. After selecting the GW device 20V-1, the packet transfer device 10-1 does not transfer packets from the other GW devices 20V-2 to 20V-m to the PPPoE terminal 60-3. Thereafter, the PPPoE terminal 60-3 communicates with the VoIP network 3 via the selected GW apparatus 20V-1 (thick broken line in FIG. 2).

  The configuration of the packet transfer apparatus will be described with reference to FIG. In FIG. 3, the packet transfer apparatus 10 includes (4 + n + m) line interfaces 11 to which individual ports (Port-1 to Port-4 + n + m) are assigned, and an internal switch 12 connected to these line interfaces 11. The communication control packet transmission buffer 13T and the reception buffer 13R, the control processor 14, and the memory 15. A control terminal 70 is connected to the packet transfer apparatus 10.

  The internal switch 12 and the control processor 14 control packet transfer between the line interfaces 11. The memory 15 stores a communication control routine 16 executed by the processor, a Service Name management table 151, a PADO waiting management table 152, and a port management table 153. The communication control routine 16 includes various control packet reception processing routines and a load distribution processing routine which will be described later. The Service Name management table 151 specifies the type of communication control packet to be processed by the control processor 14. When the operator operates the control terminal 70 to rewrite the contents of the Service Name management table 151, the operation of the control processor 14 can be changed. The PADO waiting management table 152 and the port management table 153 will be described in detail with reference to FIGS.

  When the packet transfer apparatus 10 is the packet transfer apparatus 10-1 of the access network 1 shown in FIG. 1, the line interface 11 is a communication protocol applied on the accommodated line such as Ethernet, ATM, POS (PPP over SONET) or the like. Frame termination function corresponding to When the packet transfer apparatus 10 is a packet transfer apparatus 10-2 that accommodates a PON, the line interface 11 has an OLT function that terminates a PON frame such as GE-PON, G-PON, WDM-PON, and the like. Become.

  With reference to FIG. 4, the format structure of the PADI packet will be described. In FIG. 4, the PADI packet 900 is composed of an Ethernet header 910, a PPPoE header 920, and a payload 930. The Ethernet header 910 includes a transmission destination MAC address 911, a transmission source MAC address 912, and a protocol type 913. The PPPoE header 920 includes a version 921, a type 922, a code 923, a session ID 924, and a length 925. The payload 930 includes TAG931 and the rest is Don't Care (D.C.).

  The configuration of the TAG format will be described with reference to FIG. In FIG. 5, the TAG 931 includes a TAG type 9311, a TAG length 9312, and a TAG VALUE 9313. When setting the Service Name, the terminal 60 sets 0x0101 to the TAG type 9311, and sets Service Name to the TAG VALUE 9313 field. The packet transfer apparatus 10 determines whether the TAG length is 0 based on the TAG length 9312. Further, the packet transfer apparatus 10 determines Service Name by comparing with TAG VALUE9313.

  The configuration of the Service Name management table will be described with reference to FIG. In FIG. 6, the Service Name management table 151 includes Service Name 1511, Port No. 1512. The packet transfer apparatus 10 uses a port number to be used according to the type of Service Name 1511 set in the PADI packet. Specify 1512. Here, if Service Name is not specified, port 5 and port (4 + n) are used. If Service Name is WEB, Port 5 and port (4 + n) are used. Similarly, Service Name is VoIP. In this case, port (5 + n) and port (4 + n + m) are set to be used.

  The configuration of the port management table will be described with reference to FIG. In FIG. 7, the port management table 153 includes a port number. 1531, a MAC address 1532, a transmission counter 1533, and a reception counter 1534. The port management table 153 indicates the port number of the line interface 11. And each table entry has a port number. Reference numeral 1531 denotes a source MAC address 1532 of each packet received from the line interface, a transmission counter 1533, and a reception counter 1534. Here, the port management table 153 includes the port number. 2 and the MAC address value, the packet transfer apparatus 10-1, the PPPoE terminals 60-1 to 60-4, the GW apparatus 20I-1 in the network configuration schematically shown in FIG. The connection relationship with 20I-n, 20V-1, and 20V-m is shown. The transmission counter 1533 and the reception counter 1534 are counters that are incremented when a packet is transmitted or received from the port. The maximum value of the counter is “9999”.

  The configuration of the PADO waiting management table will be described with reference to FIG. In FIG. 8, the PADO waiting management table 152 includes a terminal MAC address 1521, a GW MAC address 1522, and a reception counter 1523. FIG. 8A shows the PADO waiting management in a state where the PADI packet transmission source terminal MAC address is registered in the terminal MAC address 1521 when the packet transfer apparatus 10 receives the PADI packet and transmits the PADI packet to the GW apparatus. It is a table. On the other hand, FIG. 8B is a PADO waiting management table when the packet transfer apparatus 10 transmits a PADO packet. If the terminal MAC address is registered in FIG. 8A, the packet transfer apparatus 10 receives the PADO packet, transmits the PADO packet to the terminal, and then clears the MAC address (FIG. 8B). If the transmission destination MAC address is not registered, the packet transfer apparatus 10 does not transmit the PADO packet to the terminal.

  Next, PPPoE connection control by the packet transfer apparatus will be described with reference to FIGS. In the first embodiment, a case will be described in which the packet transfer apparatus 10-1 validates the first received PADO packet received from the GW apparatus 20I-1 or GW apparatus 20I-n.

  FIG. 9 is a sequence diagram in the case where WEB is designated in the Service Name of the PADI packet. In FIG. 9, the terminal 60-1 transmits a PADI packet of Service Name: WEB to the packet transfer device (S11). The packet transfer apparatus 10-1 searches the Service Name management table and determines the transmission port. Further, the packet transfer apparatus 10-1 registers the MAC address “00-00-00-00-00-01” of the transmission source terminal in the PADO waiting management table 152 as shown in FIG. 8A (S12). Then, the packet transfer apparatus 10-1 transmits the PADI packet only to the GW apparatuses 20I-1 and 20I-n of the same Service Name connected to the searched transmission port (S13, S14). The packet transfer apparatus 10-1 does not transmit a PADI packet to the GW apparatuses 20V-1 and 20V-m having different Service Names.

  The GW devices 20I-1 and 20I-n that have received the PADI packet transmit the PADO packet to the packet transfer device 10-1 (S16, S19). Here, it is assumed that the PADO packet from the GW 20I-1 has reached the packet transfer apparatus 10 first. The packet transfer apparatus 10-1 refers to the PADO waiting management table 152 in FIG. Since the transmission destination MAC address “00-00-00-00-00-01” is registered, the packet transfer apparatus 10-1 deletes the record of the MAC address in the PADO waiting management table (S17). The packet transfer apparatus 10-1 transmits a PADO packet to the terminal 60-1 (S18). In sequence 19, the packet transfer apparatus 10-1 receives the PADO packet from the GW 20I-n. However, since there is no registration in the PADO waiting management table 152, the packet transfer apparatus 10-1 discards the PADO packet (S21).

  When receiving the PADO packet from the packet transfer apparatus 10-1, the terminal 60-1 transmits the PADR packet to the GW apparatus 20I-1 (S22). The GW apparatus 20I-1 that has received the PADR packet assigns a session ID and returns a PADS packet to the terminal 60-1 (S23).

  When the PPPoE discovery stage is completed and the PPPoE session is established by the above operation, PPP communication using the assigned session ID is performed in the PPPoE session stage, and the terminal 60 transmits the Internet via the GW device 20I-1. WEB access is possible. When the PPP communication is terminated, the terminal 60-1 transmits a PADT (PPPoE Active Discovery Terminate) packet to the GW apparatus 20I-1 (S24). The PADT packet is a packet for requesting the end of the PPPoE session.

  With reference to FIG. 10, the operation when the packet transfer apparatus receives a PADI packet will be described. In FIG. 10, the packet transfer apparatus 10-1 receives the PADI packet from the terminal 60 by the line interface unit 11 and transmits it to the reception buffer 13 </ b> R via the internal switch 12. The control processor 14 reads out the PADI packet from the reception buffer 13R using the Service Name management table 151. The control processor 14 determines the type of the TAG value 9313 from the TAG type 9311 (S31). The control processor 14 reads the TAG length 9312 and the TAG VALUE 9313, and determines whether or not Service Name is specified (S32).

  If the Service Name is specified, the control processor 14 extracts the Service Name (S33). The control processor 14 searches for the Service Name 1511 in the Service Name management table 151 (S34). The control processor 14 determines whether or not the extracted Service Name matches the record of the Service Name 1511 (S36). If the Service Name matches, the control processor 14 registers the source MAC address in the PADO waiting management table 152 (S37), transmits the PADI packet to the corresponding GW apparatus 20 (S38), and ends. If the Service Name does not match in Step 36, the control processor 14 discards the PADI packet (S39) and ends. If service name is not specified in step 32, the control processor 14 jumps to step 33 and transitions to step 34.

With reference to FIG. 11, the operation when the packet transfer apparatus receives a PADO packet will be described. In FIG. 11, the line interface unit 11 included in the packet transfer apparatus 10-1 receives the PADO packet from the GW apparatus 20. The PADO packet is stored in the reception buffer 13R via the line interface unit 11. The control processor 14 reads the PADO packet from the reception buffer 13R and reads the transmission destination MAC address (S51). The control processor 14 determines whether there is a transmission destination MAC address in the PADO waiting management table 152 (S52). If there is a destination MAC address (S52: YES), the control processor 14 clears the record of the MAC address in the PADO waiting management table 152 (S53). The control processor 14 transmits a PADO packet to the terminal 60 (S54) and ends. If NO in step 52, the control processor 14 discards the PADO packet (S56) and ends.
According to the present embodiment, in a communication system that performs communication using PPPoE, it is possible to provide a packet transfer apparatus that requests connection of a terminal only to a communication network requested by the terminal.

  A second embodiment of PPPoE connection control will be described with reference to FIGS. Here, FIG. 12 is a diagram for explaining the transition of the contents of the PADO waiting management table. FIG. 13 is a sequence diagram of the terminal, the packet transfer device, and the GW device. 14 to 16 are flowcharts of the packet transfer apparatus.

  In the second embodiment, among the PADO packets received by the packet transfer apparatus 10-1 illustrated in FIG. 2 from the GW apparatus 20, the GW apparatus having the lowest reception counter 1534 is assigned to the GW apparatus having the highest priority. A case where the selected method is adopted will be described. Here, it is assumed that a PADI packet is received from the terminal 60-3, and PADO packets corresponding to the PADI packet are received in the order of the GW device 20V-m and the GW device 20V-1.

  First, the transition of the contents of the PADO waiting management table will be described with reference to FIG. FIG. 12A shows the PADO waiting management table 152 after receiving the PADI packet from the terminal 60-3. The terminal MAC address 1521 records “00-00-00-00-00-03” that is the MAC address of the terminal 60-3, and the reception counter 1523 records “9999” that is the maximum value. . FIG. 12B shows the PADO waiting management table 152 after the PADO packet is received from the GW apparatus 20V-m. In the GW MAC address, “00-00-00-00-00-08”, which is the MAC address of the GW device 20V-m, is recorded, and the reception counter 1523 receives the reception counter of the connection port of the GW device 20V-m. “732” of 1534 is recorded.

  FIG. 12C shows the PADO waiting management table 152 after the PADO packet is received from the GW apparatus 20V-1. In the GW MAC address, “00-00-00-00-00-07”, which is the MAC address of the GW device 20V-1, is recorded, and the reception counter 1523 stores the reception counter of the connection port of the GW device 20V-1. “453” of 1534 is recorded. FIG. 12D is a PADO waiting management table 152 when the packet transfer apparatus 10-1 transmits a PADO packet. The terminal MAC address 1521, the GW MAC address 1522, and the reception counter 1523 are all cleared.

  With reference to FIG. 13, the operation when the packet transfer apparatus receives the PADO packet in the case where VoIP is specified in the Service Name of the PADI packet will be described. In FIG. 13, the terminal 60-3 transmits a PADI packet in which VoIP is specified for Service Name to the packet transfer apparatus 10-1 (S61). The packet transfer apparatus 10-1 performs the Service Name determination process, and registers the MAC address and the reception counter maximum value of the terminal 60-3 in the PADO waiting management table 152 as shown in FIG. 12A (S62). . The packet transfer apparatus 10-1 starts a PADO transmission timer (S63). Since the service name is VoIP, the packet transfer apparatus 10-1 transmits the PADI packet to the GW apparatuses 20V-1 and 20V-m (S64, S66).

  The GW apparatus 20V that has received the PADI packet transmits the PADO packet to the packet transfer apparatus 10 (S67, S69). The packet transfer apparatus 10-1 performs GW apparatus selection processing (S68, S71). Here, when the PADO transmission timer times out, the packet transfer apparatus 10-1 clears the corresponding record in the PADO waiting management table 152 (S72). The packet transfer apparatus 10-1 transmits a PADO packet to the terminal 60-3 (S73).

  Note that the transmission of the PADR packet (S74) and the transmission of the PADS packet (S76) are the same as in FIG. Further, the PADO waiting management table 152 after step 68 is shown in FIG. The PADO waiting management table 152 after step 71 is shown in FIG.

  Next, an operation flow of the packet transfer apparatus when a PADO packet for the PADI packet is received from the GW apparatus 20V will be described with reference to FIG. In FIG. 14, when receiving the PADO, the control processor 14 extracts the transmission destination MAC address (S81). The control processor 14 determines whether the terminal MAC address 1521 of the PADO waiting management table 152 is entered (S82). If there is an entry (YES), the control processor 14 executes GW device selection processing (described later in FIG. 15) (S83) and ends. If there is no entry in step 82 (NO), the control processor 14 discards the PADO packet (S84) and ends.

  The GW selection process will be described with reference to FIG. The GW selection process (S83) is a process of extracting a transmission source with the highest priority from the transmission sources of the received PADO packet. The control processor 14 searches the reception counter 1534 of the port management table 153, and extracts the GW device with the smallest reception number (S831). The control processor 14 determines whether the transmission source of the PADO packet is the GW device with the smallest number of receptions (S832). If it is a PADO packet from the smallest reception number GW device, the control processor 14 ends the GW device selection process. If NO in step 82, the control processor 14 compares with the reception counter 1523 of the PADO waiting management table (S833). The control processor 14 determines whether or not the reception counter of the received PADO packet transmission source is small (S834). If equal or larger (NO), the control processor 14 discards the PADO packet (S837) and ends. If it is smaller in step 834 (YES), the control processor 14 updates the GW MAC address 1522 and the reception counter 1523 in the PADO waiting management table (S836) and ends.

With reference to FIG. 16, the monitoring process of the PADO transmission timer of the packet transfer apparatus will be described. The monitoring process of the PADO transmission timer is started with the start of the PADO transmission timer, and the control processor 14 determines whether the timer value is 0 (timeout) (S91). If NO, the process returns to step 91. If YES, the control processor 14 deletes the information of the corresponding record in the PADO waiting management table 152 (S92). The control processor 14 transmits a PADO packet to the corresponding terminal (S93) and ends.
According to the present embodiment, access is not concentrated on a specific GW apparatus when a session is established.

1 is a block diagram of a communication system. 1 is a block diagram of a communication system. It is a block diagram of a packet transfer apparatus. It is a figure explaining the format of PADI. It is a figure explaining the format of TAG. It is a figure explaining a Service Name management table. It is a figure explaining a port management table. It is a figure explaining a PADO waiting management table. It is a sequence diagram among a terminal, a packet transfer apparatus, and two GWs. It is a flowchart of PADI reception of a packet transfer apparatus. It is a flowchart of PADO reception of a packet transfer apparatus. It is a figure explaining the transition of the content of the PADO waiting management table. It is a sequence diagram with a terminal, a packet transfer apparatus, and a GW apparatus. It is a flowchart of a packet transfer apparatus. It is a flowchart of a packet transfer apparatus. It is a flowchart of a packet transfer apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Access network, 2 ... Internet, 3 ... VoIP network, 10 ... Packet transfer apparatus, 11 ... Line interface, 12 ... Internal switch, 13 (13T, 13R) ... Transmission / reception buffer, 14 ... Control processor, 15 ... Memory, 16 ... Communication control routine, 20 ... GW device, 30 ... L2SW, 40 ... WEB server, 50 ... SIP server, 60 ... Terminal, 70 ... Control terminal, 80 ... ONU, 90 ... Star coupler, 100 ... Communication network.

Claims (4)

A plurality of line interfaces; internal switches connected to these line interfaces; transmission buffers and reception buffers connected to the internal switches; a control processor for controlling the internal switches, the transmission buffers, and the reception buffers; In a packet transfer device comprising a memory for holding a program of this control processor,
The memory holds a service management table that associates the line interface numbers corresponding to a plurality of connected gateway devices with services of the gateway devices,
When a connection request packet specifying a service is received from a connected terminal, the destination gateway device of the connection request packet is specified by referring to the service management table, and the connection request packet is sent to the specified gateway device. A packet transfer apparatus for transferring. The packet transfer apparatus according to claim 1, wherein
When a plurality of connection response packets are received from the specified gateway device, the packet transfer device transfers the specific connection response packet to the terminal. The packet transfer device according to claim 2, wherein
A packet transfer apparatus that identifies the specific connection response packet from the plurality of connection response packets based on a first-come-first-served basis or a reception count. A plurality of line interfaces; internal switches connected to these line interfaces; transmission buffers and reception buffers connected to the internal switches; a control processor for controlling the internal switches, the transmission buffers, and the reception buffers; In a packet transfer method in a packet transfer device comprising a memory for holding a program of the control processor,
Holding a service management table associating the line interface numbers corresponding to a plurality of gateway devices connected to the memory and services of the gateway devices;
Receiving a connection request packet specifying a service from a connected terminal;
Referring to the service management table;
Identifying a destination gateway device of the connection request packet;
And a step of transferring the connection request packet to the identified gateway device.

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