JP4775716B2 - Relay device, relay method, and relay program - Google Patents

Description

  The present invention relates to a relay device, a relay method, and a relay program, and more particularly to a relay device, a relay method, and a relay program used in multicast communication.

  Protocols applied to multicast communication include IGMP (internet group management protocol) and MLD (multicast listener discovery). IGMP is a protocol applied to multicast communication in IPv4, and MLD is a protocol applied to multicast communication in IPv6. Both IGMP and MLD specify the same operation. Even if both IGMP and MLD are applied to multicast communication, IGMP and MLD do not affect each other's operation. Hereinafter, IGMP / MLD, or that both IGMP and MLD are applied is referred to as IGMP / MLD.

  Packets transmitted by multicast (hereinafter referred to as multicast packets) are distinguished in units called groups. This group is called a multicast group. A multicast address is determined for each multicast group. The start of reception of a multicast packet of a certain multicast group is expressed as joining a multicast group. In addition, it is expressed that the client stops receiving the multicast packet of a certain multicast group as leaving the multicast group.

  In some cases, the reception of a multicast packet of a certain multicast group by a client is expressed as viewing of the multicast group. For example, a client viewing a multicast group means a client receiving a multicast packet of the multicast group.

  In the following description, a multicast packet of a certain multicast group is simply referred to as a multicast group packet.

  In a system that performs multicast transmission using IGMP / MLD, a device that is a transmission source of a multicast packet (hereinafter referred to as a transmission source server) transmits a packet of the multicast group. A relay device (for example, a multicast router) transmits a packet of the multicast group to each client that has joined the multicast group. A client that performs communication using IGMP / MLD is hereinafter referred to as an IGMP / MLD client. Here, a case where the relay device is a multicast router will be described as an example.

  The multicast router transmits a general query packet (hereinafter referred to as a GQ packet) or a group specific query packet (hereinafter referred to as a GSQ packet) to the IGMP / MLD client. Check the status. That is, it is confirmed which multicast group each client is receiving, and which client is receiving a particular multicast group packet. The GQ packet is used to confirm the multicast group that each client is viewing. The GSQ packet is used to check whether there is a client who is viewing a specific multicast group.

  When an IGMP / MLD client newly joins a multicast group, an IGMP / MLD Membership Report packet (hereinafter referred to as an MR packet) requesting the IGMP / MLD client itself to transmit a packet of the multicast group. Send to multicast router. When an IGMP / MLD client viewing a multicast group receives a GQ packet or a GSQ packet, the IGMP / MLD client transmits an MR packet within the time specified by the GQ packet or the GSQ packet to view the multicast Inform the group. However, before an IGMP / MLD client transmits an MR packet for notifying a multicast group being viewed in response to a GQ packet or a GSQ packet, an MR packet for notifying the multicast group is transmitted by another IGMP / MLD client. When the MR packet is received, the MR packet is not transmitted.

  When the IGMP / MLD client stops viewing the multicast group, the IGMP / MLD client transmits a multicast group leaving packet (hereinafter referred to as a group leaving packet) requesting to stop transmission of the packet of the multicast group to the multicast router. The multicast router that has received the group leaving packet inquires whether the multicast group is being viewed in order to check whether there is another IGMP / MLD client that is viewing the multicast group that is requested to stop transmission. GSQ packet is transmitted. If the response to the GSQ packet is not within the predetermined time (Max Response Time) (when no MR packet is received), the multicast router is requested to stop transmission other than the IGMP / MLD client that transmitted the group leaving packet. It is determined that there is no IGMP / MLD client viewing the group, and distribution of the multicast group is stopped. On the other hand, when the MR packet is received within a predetermined time (Max Response Time) after transmitting the GSQ packet, distribution of the multicast group is continued.

  As described above, in IGMP / MLD, the multicast router is designed with a policy of managing only the viewing state of the multicast group. Therefore, when each IGMP / MLD client leaves the multicast group, the multicast router It is necessary to check by sending a GSQ packet whether there is another IGMP / MLD client viewing the group. There is a problem that multicast packet distribution cannot be stopped during a predetermined time (Max Response Time) for waiting for a response to the GSQ packet. In particular, when a channel switching operation called zapping is performed at a high speed, joining and leaving the multicast group are repeated, so that a state in which many multicast groups are temporarily joined occurs. As a result, there is a problem that a large amount of data flows, exceeds the performance of the transmission medium and the relay device, and data transmitted by multicast cannot be transferred.

  A general IGMP / MLD snooping device described in RFC4545 and the like is equipped with a function called “Fast-Leave” in order to solve this problem. FIG. 7 is an explanatory diagram showing an example of a general IGMP / MLD snooping device. On the downstream port side of the IGMP / MLD snooping device 20, the IGMP / MLD clients 21-24 receive multicast packets. In the example illustrated in FIG. 7, the IGMP / MLD clients 23 and 24 transmit and receive packets to and from the IGMP / MLD snooping device 20 via the L2 switch 25.

  The IGMP / MLD snooping device 20 manages a multicast group that is viewed on the downstream port side. The IGMP / MLD packets transmitted from the IGMP / MLD clients 21 to 24 are not transferred to the downstream port side, and the group leaving packet is uploaded only when there is no IGMP / MLD client watching on the downstream port. Forward to the upstream port. An IGMP / MLD packet is a control packet defined by IGMP or MLD. Through the processing as described above, in the general IGMP / MLD snooping device 20, the IGMP / MLD client joined to the multicast group is directly connected to the downstream port like the IGMP / MLD clients 21 and 22 illustrated in FIG. If it is guaranteed that only the IGMP / MLD client has been made, distribution of the multicast group can be stopped immediately after receiving the group leave packet from the IGMP / MLD client. This function is the Fast-Leave function.

  An example of a data distribution system is described in Patent Document 1. When a data distribution system described in Patent Document 1 receives a Report packet indicating a reception start request from a client via a certain network, the MAC address of the client is stored in a subscription state table corresponding to the network. Register and start distributing multicast data. Thereafter, when a Leave Group packet is received from the client, the MAC address of the client is deleted from the subscription state table.

  An example of a routing device is described in Patent Document 2. Patent Document 2 describes that a routing device counts the number of clients participating in a multicast group for each multicast group.

Japanese Patent Laying-Open No. 2003-244230 (paragraphs 0048-0057, FIG. 2) JP 2004-56584 A (paragraph 0015)

  The general IGMP / MLD snooping device illustrated in FIG. 7 has the following problems.

  The IGMP / MLD clients 23 and 24 (see FIG. 7) connected to the downstream port of the IGMP / MLD snooping device 20 via the L2 switch 25 detect each other's MR packet. If there are multiple IMGP / MLD clients in one downstream port, like this IGMP / MLD client 23, 24, the IGMP / MLD client detects each other's MR packet, so the Fast-Leave function is enabled. As a result, the same multicast group cannot be viewed simultaneously by two IGMP / MLD clients.

  In addition, since the Fast-Leave function can only be turned on or off at each port, the Fast-Leave function can be used in an environment where multiple IGMP / MLD clients may be connected to one downstream port. Cannot be used.

  As described above, in the Fast-Leave function, when the connection configuration of the IMGP / MLD client connected to the downstream port is clear, the Fast-Leave function can be set to an optimum setting by turning the Fast-Leave function on or off. . However, in a service that actually distributes multicast packets, it is difficult to guarantee the connection configuration of the IMGP / MLD client connected to the downstream port. Therefore, even when the Fast-Leave function can be turned on, there is a problem that the Fast-Leave function cannot be used in many cases.

  Further, even if the invention described in Patent Document 1 is applied to a relay device, it is determined whether or not the Fast-Leave function can be applied to a port in which client information is not registered in the joining state table. I can't.

  Therefore, an object of the present invention is to provide a relay device, a relay method, and a relay program that can learn a downstream port capable of fast-leaving.

The relay device of the present invention is a relay device that relays multicast packets, and is provided with a plurality of ports to which clients that receive multicast packets are connected, and holds a MAC address learning table that associates MAC addresses with ports. And a control unit that transmits an inquiry packet for inquiring whether or not a multicast group that is a group of multicast packets has been received, and the control unit connects the client that has requested transmission of the multicast group to the client. Client management database storage means for storing a client management database associated with a port, a port to which a client that has requested transmission of a multicast group is connected, and the multicast group Multicast group management database storage means for storing a multicast group management database in which identification information is associated with a lifetime that is a time to wait for a response to an inquiry packet; and when a transmission request packet requesting transmission of a multicast group is received The port that received the transmission request packet, the identification information of the multicast group, and the lifetime determined for the multicast group are associated with each other and registered in the multicast group management database, and the multicast MAC address of the multicast group Registration means for associating the port that received the transmission request packet with the MAC address learning table of the switch unit, and stopping the transmission of the multicast group An inquiry means for sending an inquiry packet for inquiring whether or not the multicast group has been received when a group leaving packet to be requested is received; When the number of clients corresponding to the port that received the leave packet is one or more, and when the number of clients corresponding to the port that received the group leave packet is one, transmitted by the group leave packet The leaving processing means for deleting the entry corresponding to the multicast group requested to be stopped from the multicast group management database and the MAC address learning table of the switch unit, and the inquiry means are the multicast group. After transmitting the inquiry packet for inquiring whether or not the packet is received, when a transmission request packet for requesting transmission of the multicast group is received as a response to the inquiry packet, the port that received the transmission request packet is set to the client Learning means that learns as a port that cannot leave at high speed, and when there are multiple clients corresponding to the port that received the group leaving packet, the lifetime corresponding to the multicast group that was inquired by the inquiry packet is determined in advance. A lifetime shortening means that shortens the transmission request time when the learning means receives the transmission request packet after the inquiry packet has been transmitted and before the shortened lifetime has elapsed. Receive packet The port, the client is characterized in that it learned as a port that can not be fast withdrawal.

Also, the relay method of the present invention is provided with a plurality of ports to which clients that receive multicast packets are connected, a switch unit that holds a MAC address learning table that associates MAC addresses with ports, and a multicast that is a group of multicast packets. A client management database that includes a control unit that transmits an inquiry packet for inquiring whether or not a group is received, and in which the control unit associates a client that requests transmission of a multicast group with a port to which the client is connected Client management database storage means for storing the port, the port to which the client that requested transmission of the multicast group is connected, identification information of the multicast group, and a response to the inquiry packet A relay method applied to a multicast packet relay apparatus having a multicast group management database storage unit that stores a multicast group management database associated with a lifetime that is a waiting time, wherein the transmission requests multicast group transmission When the request packet is received, the port that received the transmission request packet, the identification information of the multicast group, and the lifetime determined for the multicast group are associated and registered in the multicast group management database, The multicast MAC address of the multicast group and the port that received the transmission request packet are associated with each other and registered in the MAC address learning table of the switch unit. When a group leaving packet requesting to stop transmission is received, an inquiry packet for inquiring whether or not the multicast group has been received is transmitted, and when a group leaving packet is received, the client management database is referred to Judgment is made on whether the number of clients corresponding to the port that received the leave packet is one or more, and when the number of clients corresponding to the port that received the group leave packet is one, transmission stop was requested by the group leave packet Queries when an entry corresponding to a multicast group is deleted from the multicast group management database and the MAC address learning table of the switch unit, and there are multiple clients corresponding to the port that received the group leaving packet. As a response to the inquiry packet after sending the inquiry packet to inquire whether the multicast group has been received or not , the lifetime corresponding to the multicast group that is the target of inquiry by the packet packet is shortened from a predetermined time. When the transmission request packet for requesting transmission of the multicast group is received before the shortened lifetime elapses, the port that has received the transmission request packet is learned as a port from which the client cannot leave at high speed. Features.

The relay program of the present invention is provided with a plurality of ports to which clients that receive multicast packets are connected, and can access the MAC address learning table of the switch unit that holds the MAC address learning table that associates the MAC address with the port. Yes, a client management database storage unit that stores a client management database that associates a client that has requested transmission of a multicast group with a port to which the client is connected, and a port to which a client that has requested transmission of a multicast group is connected And a multicast group management database that associates the identification information of the multicast group with the lifetime that is the time to wait for a response to the inquiry packet A relay program installed in a computer comprising a multicast group management database storage means, and when the computer receives a transmission request packet requesting transmission of a multicast group, the port that has received the transmission request packet; The multicast group identification information and the lifetime determined for the multicast group are associated and registered in the multicast group management database, and the multicast MAC address of the multicast group and the port that received the transmission request packet are When a registration process for registering in the MAC address learning table of the switch unit in association with each other and a group leaving packet requesting to stop transmission of the multicast group are received, the multicast group is received. Inquiry processing for sending an inquiry packet for inquiring whether or not a group has been received. When a group leave packet is received, the client management database is referred to, and the number of clients corresponding to the port that received the group leave packet is 1 If the number of clients corresponding to the port that received the group leaving packet is 1, the entry corresponding to the multicast group requested to stop transmission by the group leaving packet is multicast. Deletion processing to be deleted from the group management database and the MAC address learning table of the switch unit , and inquiry by inquiry packet when there are multiple clients corresponding to the port that received the group leave packet Response to the inquiry packet after sending an inquiry packet for inquiring whether or not the multicast group is received , and a lifetime reduction process for shortening the lifetime corresponding to the target multicast group from a predetermined time. Learning that, when a transmission request packet for requesting transmission of the multicast group is received before the shortened lifetime elapses, the port that has received the transmission request packet is learned as a port that the client cannot leave at high speed Processing is executed.

  According to the present invention, it is possible to automatically learn a port from which the client cannot leave at high speed. As a result, a port that is not a port from which the client can leave at high speed is defined as a fast-leaveable downstream port. Can learn.

Embodiments of the present invention will be described below with reference to the drawings.
In the following description of each embodiment, a group of multicast packets distinguished as a group is called a multicast group. In addition, the fact that an IGMP / MLD client starts receiving a multicast packet of a certain multicast group is described as joining a multicast group. In addition, the fact that the IGMP / MLD client stops receiving a multicast packet of a certain multicast group is described as leaving the multicast group. In addition, viewing a multicast group means receiving a packet of the multicast group. The IGMP / MLD packet is a control packet defined by IGMP or MLD, and examples of the IGMP / MLD packet include an MR packet, a group leaving packet, a GQ packet, and a GSQ packet.

Example 1.
FIG. 1 is a block diagram showing an example of the relay device of the present invention. In the first embodiment, description will be made assuming that the relay device is an IGMP / MLD snooping device having an IGMP / MLD snooping function. IGMP / MLD snooping refers to transmitting a packet of a certain multicast group only from a port to which an IGMP / MLD client viewing the multicast group is connected. IGMP / MLD is applied to the IGMP / MLD snooping device 1.

  As shown in FIG. 1, the IGMP / MLD snooping device (relay device) 1 includes an IGMP / MLD processing unit 11 and an L2 switch unit with an IGMP / MLD snooping function (hereinafter referred to as an L2 switch unit) 12. . The IGMP / MLD processing unit 11 is provided with an upstream port (upstream port), and the L2 switch unit 12 is provided with a plurality of downstream ports (downstream ports). The IGMP / MLD processing unit 11 receives a multicast packet from a transmission source server (not shown) via an upstream port. Further, an IGMP / MLD client is connected to the downstream port. In FIG. 1, FIG. 2, and FIG. 6, the illustration of the IGMP / MLD client is omitted. The connection mode between the downstream port and the IGMP / MLD client may be any of the following. That is, the IGMP / MLD client may be directly connected to the downstream port. Further, as in the IGMP / MLD clients 23 and 24 shown in FIG. 7, the IGMP / MLD client may be connected to the downstream port via an L2 switch or the like provided separately from the IGMP / MLD snooping device 1. .

  The configuration of the L2 switch unit 12 is the same as the L2 switch with IGMP / MLD snooping function known to those skilled in the art. In the following description, the description of the L2 switch unit 12 is omitted except for the operation related to the present invention. .

  The IGMP / MLD processing unit 11 receives the IGMP / MLD packet received from the IGMP / MLD client by the L2 switch unit 12 from the L2 switch unit 12. Then, the IGMP / MLD processing unit 11 learns the multicast group viewed at each downstream port and the IGMP / MLD client viewing the multicast group. In other words, the IGMP / MLD processing unit 11 determines, based on the IGMP / MLD packet received from the L2 switch unit 12, the multicast group viewed by the IGMP / MLD client and the IGMP / MLD client viewing the multicast group. And manage. The IGMP / MLD processing unit 11 analyzes the received IGMP / MLD packet, performs processing in response to a request for joining or leaving the multicast group, and receives the received IGMP / MLD packet from the upstream port. Forward.

  Further, the IGMP / MLD processing unit 11 registers information on the multicast group viewed by the IGMP / MLD client connected to each downstream port in the L2 switch unit 12. Specifically, a multicast MAC address is registered as multicast group information.

  Further, the IGMP / MLD processing unit 11 transfers the packet received from the upstream port to the L2 switch unit 12.

  Specific contents of the processing of the IGMP / MLD processing unit 11 will be described later.

  When receiving the IGMP / MLD packet transmitted from the IGMP / MLD client from the downstream port, the L2 switch unit 12 transfers the IGMP / MLD packet only to the IGMP / MLD processing unit 11. The L2 switch unit 12 does not transfer the IGMP / MLD packet received from the downstream port from another downstream port.

  In addition, the L2 switch unit 12 uses the multicast MAC address and the downstream port information registered in the MAC address learning table by the IGMP / MLD processing unit 11 to transfer the multi-cast packet transferred from the IGMP / MLD processing unit 11. To the IGMP / MLD client.

  FIG. 2 is a block diagram showing the IGMP / MLD snooping device (relay device) shown in FIG. 1 in more detail. The same components as those shown in FIG. 1 are denoted by the same reference numerals as those in FIG.

  The L2 switch unit (L2 switch unit with IGMP / MLD snooping function) 12 includes a storage device (not shown) for registering a MAC address learning table. The L2 switch unit receives the IGMP / MLD packet transmitted from the IGMP / MLD client from the downstream port, and performs a bridge process. The MAC address learning table is a table in which each downstream port is associated with a MAC address. When transmitting a packet from the downstream port, the L2 switch unit 12 transmits the packet from the downstream port corresponding to the MAC address that is the destination of the packet. In addition, when a packet is received from a client, the bridge process stores the correspondence between the MAC address of the client (source MAC address of the received packet) and the downstream port that received the packet in the MAC address learning table. It is a process to register. In the present invention, in the MAC address learning table, not only the correspondence between the client MAC address and the downstream port, but also the correspondence between the multicast MAC address and the downstream port is registered. The correspondence between the multicast MAC address and the downstream port is registered by the IGMP / MLD processing unit 11.

  Further, as described above, when receiving the IGMP / MLD packet from the downstream port, the L2 switch unit 12 transfers the IGMP / MLD packet only to the IGMP / MLD processing unit 11.

  The IGMP / MLD processing unit 11 manages the multicast group and the IGMP / MLD client viewing the multicast group, and performs processing in response to a request for joining the multicast group or leaving the multicast group. And so on.

  The configuration of the IGMP / MLD processing unit 11 and the specific processing contents will be described. As shown in FIG. 2, the IGMP / MLD processing unit 11 includes an IGMP / MLD packet analysis / transmission / reception unit 111, an IGMP / MLD client management database unit 112, a multicast address management unit 113, a multicast group management database unit 114, Is provided. Hereinafter, the IGMP / MLD client management database unit 112 is referred to as an IGMP / MLD client management DB unit 112, and the multicast group management database unit 114 is referred to as a multicast group management DB unit 114.

  The multicast group management DB unit 114 is a storage device that stores a multicast management DB (database). FIG. 3 is an explanatory diagram showing an example of the multicast group management DB. As shown in FIG. 3, the multicast management DB is called a port number, a multicast address of a multicast group viewed by an IGMP / MLD client, and an IP address (“Source Specific Address”) of a transmission source server of the multicast group. ) And lifetime.

  The port number is port identification information for identifying each downstream port. Here, a case where the port identification information is a number is illustrated, but the port identification information is not limited to a number.

  The multicast address included in the multicast management DB is a multicast IP address added as a transmission destination to the multicast packet when the transmission source server transmits the packet of the multicast group.

  The IP address (Source Specific Address) of the transmission source server is the IP address of the transmission source server that transmits the packet of the multicast group. The multicast group can be managed by the multicast IP address and the IP address of the transmission source server. The IP address (Source Specific Address) of the transmission source server is optionally used when applying IGMPv3 / MLDv2. When IGMP / MLD of a version other than IGMPv3 / MLDv2 is applied and Source Specific Address is not used, the multicast group may be identified by the multicast IP address.

  The lifetime is a time for waiting for a response from the IGMP / MLD client after transmitting the GQ packet or the QSQ packet. If there is no response indicating that the multicast group is being viewed within a certain time after transmission of the GQ packet or GSQ packet, it is determined that there is no IGMP / MLD client viewing the multicast group. The lifetime is this fixed time. Therefore, after transmitting a GQ packet or a GSQ packet, there is no IGMP / MLD client viewing the multicast packet unless an MR packet designating the multicast group is received before the lime time corresponding to the multicast group elapses. It is determined not to. The lime time is predetermined for each multicast group. The time for waiting for a response to a GQ packet (Max Response Time) and the time for waiting for a response to a GSQ packet may be set as different values.

  The IGMP / MLD client management DB unit 112 is a database that stores an IGMP / MLD client management DB (database). FIG. 4 is an explanatory diagram showing an example of the IGMP / MLD client management DB. As shown in FIG. 4, the IGMP / MLD client management DB associates the port number with the MAC address of the transmission source of the IGMP / MLD packet (that is, the MAC address of the IGMP / MLD client that transmitted the IGMP / MLD packet). A collection of data. By referring to the IGMP / MLD client management DB, it is possible to determine how many IGMP / MLD clients are connected to each downstream port. For example, in the example shown in FIG. 4, since two combinations of port number 1 and MAC address are registered, it is determined that there are two IGMP / MLD clients connected to the downstream port of port number 1. .

  The IGMP / MLD packet analysis / transmission / reception unit 111 transfers the packet received from the upstream port to the L2 switch unit 12. Therefore, when receiving the multicast packet transmitted from the transmission source server from the upstream port, the IGMP / MLD packet analysis / transmission / reception unit 111 transfers the multicast packet to the L2 switch unit 12.

  Further, the IGMP / MLD packet analysis / transmission / reception unit 111 receives from the L2 switch unit 12 a packet received by the L2 switch unit 12 from the IGMP / MLD client. If the packet received from the L2 switch unit 12 is not an IGMP / MDL packet, the IGMP / MLD packet analysis / transmission / reception unit 111 transmits the packet from the upstream port. On the other hand, if the packet received from the L2 switch unit 12 is an IGMP / MDL packet, the packet is analyzed and the addition or deletion of data regarding the multicast group to the multicast group management DB is performed according to the type of the packet. Addition of a multicast MAC address to the MAC address learning table (not shown) of the unit 12 is performed. Further, the MAC address and port number are additionally registered in the IGMP / MLD client management DB according to the type of packet.

  Further, the IGMP / MLD packet analysis / transmission / reception unit 111 periodically transmits a GQ packet via the L2 switch unit 12. At this time, the IGMP / MLD packet analysis / transmission / reception unit 111 transmits the GQ packet to the L2 switch unit 12, and the L2 switch unit 12 transmits the GQ packet from each downstream port.

  The multicast address management unit 113 monitors the multicast group management DB stored in the multicast group management DB unit 114. Then, after transmitting a GQ packet or a GSQ packet, it waits for a response from the IGMP / MLD client, and if it does not receive an MR packet designating a multicast group before a predetermined time (lifetime) elapses, the multicast The entry corresponding to the group is deleted from the multicast group management DB. The multicast address management unit 113 further deletes the entry corresponding to the multicast group from the MAC address learning table (not shown) of the L2 switch unit 12. Specifically, the entry corresponding to the multicast MAC address of the multicast group is deleted.

  Since the GQ packet is an inquiry packet for reporting all multicast groups viewed by each IGMP / MLD client, the GQ packet does not include multicast group identification information (for example, multicast address). On the other hand, the GSQ packet is a packet for inquiring whether there is a client who is viewing a specific multicast group, and therefore includes identification information (for example, a multicast address) of the multicast group.

  As already described, when receiving an GQ packet or a GSQ packet, the IGMP / MLD client notifies the multicast group being viewed within the time specified by the packet. That is, an MR packet including identification information (for example, a multicast address) of the multicast group being viewed is transmitted. However, when another IGMP / MLD client transmits an MR packet including identification information (for example, a multicast address) of the multicast group within the specified time, and receives the MR packet, the MR packet is transmitted. do not do. The IGMP / MLD client also transmits an MR packet when requesting to join a multicast group.

  The IGMP / MLD client includes the multicast IP address serving as identification information of the designated multicast group in the MR packet and transmits the MR packet. When IGMPv3 / MLDv2 is applied and a multicast group is identified by a combination of a multicast IP address and an IP address (Source Specific Address) of a transmission source server, the Source Specific Address is also included in the MR packet. Further, lifetime information corresponding to the multicast group may be included in the MR packet. Hereinafter, a case where the IGMP / MLD client includes the multicast IP address, the source specific address, and the lifetime of the designated multicast group in the MR packet will be described as an example. The manner in which the IGMP / MLD client acquires the multicast IP address, source specific address, and lifetime information is not particularly limited. For example, the information may be acquired from a server that broadcasts the information or a Web server.

Next, the operation of the present invention will be described.
The L2 switch unit 12 transmits the packet received from the downstream port to the IGMP / MLD packet analysis / transmission / reception unit 111. In particular, when the packet received from the downstream port is an IGMP / MLD packet, the packet is transmitted only to the IGMP / MLD packet analysis / transmission / reception unit 111.

  FIG. 5 is a flowchart showing an example of the operation of the IGMP / MLD packet analysis / transmission / reception unit 111 when the IGMP / MLD packet analysis / transmission / reception unit 111 receives a packet from the L2 switch unit 12. When receiving the packet from the L2 switch unit 12, the IGMP / MLD packet analysis / transmission / reception unit 111 determines whether or not the packet is an IGMP / MLD packet (step S1).

  When the packet received from the L2 switch unit 12 is not an IGMP / MLD packet (No in step S1), the IGMP / MLD packet analysis / transmission / reception unit 111 transmits the packet from the upstream port (step S10). When the packet received from the L2 switch unit 12 is an IGMP / MLD packet (Yes in step S1), the IGMP / MLD packet analysis / transmission / reception unit 111 determines whether the packet is an MR packet (step S2). ).

  When the packet received from the L2 switch unit 12 is an MR packet (Yes in step S2), the IGMP / MLD packet analysis / transmission / reception unit 111 receives the port number of the downstream port that received the MR packet, and the MR packet The source MAC address is associated and registered in the IGMP / MLD client management DB (see FIG. 4) (step S3).

  After step S3, the IGMP / MLD packet analysis / transmission / reception unit 111 registers the multicast group requested to join by the MR packet from the IGMP / MLD in the multicast group management DB. That is, the IGMP / MLD packet analysis / transmission / reception unit 111 includes the multicast IP address, the IP address (Source Specific Address) and lifetime of the source server included in the MR packet, and the port of the downstream port that has received the MR packet. The numbers are associated with each other and registered in the multicast group management DB (see FIG. 3) (step S4).

  Further, in step S4, the IGMP / MLD packet analysis / transmission / reception unit 111 associates the multicast MAC address corresponding to the multicast IP address of the designated multicast group with the port number of the downstream port that has received the MR packet. , It is registered in the MAC address learning table (not shown) of the L2 switch unit 12. The multicast MAC address is assigned to the lower 23 bits of the multicast IP address and the lower 23 bits of “01: 00: 5e: 00: 00: 00”. The IGMP / MLD packet analysis / transmission / reception unit 111 generates a multicast MAC address by assigning the lower 23 bits of the multicast IP address included in the MR packet to “01: 00: 5e: 00: 00: 00”. The multicast MAC address and the port number of the downstream port that has received the MR packet may be associated with each other and registered in the MAC address learning table of the L2 switch unit 12.

  If there is no MR packet received from the L2 switch unit 12 (No in step S2), the IGMP / MLD packet analysis / transmission / reception unit 111 determines whether the packet is a group leaving packet (step S5). ). If the received packet is not a group leaving packet (No in step S5), the IGMP / MLD packet analysis / transmission / reception unit 111 transmits the packet from the upstream port (step S10).

  When the packet received from the L2 switch unit 12 is a group leaving packet (Yes in step S5), the IGMP / MLD packet analysis / transmission / reception unit 111 transmits the GSQ packet via the L2 switch unit 12 (step S6). In step S6, the IGMP / MLD packet analysis / transmission / reception unit 111 transmits the GQ packet to the L2 switch unit 12, and the L2 switch unit 12 transmits the GSQ packet from each downstream port. Also, the IGMP / MLD packet analysis / transmission / reception unit 111 sets the Max Response Time of the GSQ packet transmitted in step S6 to be shorter than a predetermined time. For example, it is set shorter than the Max Response Time of the GQ packet.

  Next, the IGMP / MLD packet analysis / transmission / reception unit 111 refers to the IGMP / MLD client management DB to determine whether one IGMP / MLD client is registered for the downstream port that has received the group leaving packet or a plurality of IGMP / MLD clients. It is determined whether the / MLD client is registered (step S7). That is, it is determined whether one MAC address or a plurality of MAC addresses are registered corresponding to the port number of the downstream port that has received the group leaving packet.

  When a plurality of MAC addresses are registered corresponding to the port number of the downstream port that has received the group leaving packet, the IGMP / MLD packet analysis / transmission / reception unit 111 of the multicast group management DB (see FIG. 3). Among the entries, the lifetime of the entry corresponding to the multicast group requested to leave using the group leave packet is shortened to the Max Response Time value of the GSQ packet set short in Step S6 (Step S9). After step S9, the IGMP / MLD packet analysis / transmission / reception unit 111 transmits the received group leaving packet from the upstream port (step S10).

  When one MAC address is registered corresponding to the port number of the downstream port that has received the group leave packet, the IGMP / MLD packet analysis / transmission / reception unit 111 receives the group leave packet from the multicast group management DB. The entry that associates the port number of the downstream port that received the message with the multicast group requested to leave using the group leave packet is deleted (step S8). Specifically, the entry that associates the port number with the multicast address, source specific address, and lifetime of the multicast group is deleted. Further, in step S8, the IGMP / MLD packet analysis / transmission / reception unit 111 sets an entry in which the port number of the downstream port that received the group leaving packet and the multicast MAC address of the multicast group are associated with each other in the L2 switch unit 12 Are deleted from the MAC address learning table (step S8).

  After step S8, the IGMP / MLD packet analysis / transmission / reception unit 111 transmits the received group leaving packet from the upstream port (step S10).

  As already described, if the multicast address management unit 113 does not receive an MR packet designating a multicast group before the lifetime elapses, the multicast address management unit 113 deletes the entry corresponding to the multicast group from the multicast group management DB. Further, it is also deleted from the MAC address learning table (not shown) of the L2 switch unit 12. Therefore, the multicast address management unit 113 monitors the multicast group management DB stored in the multicast group management DB unit 114 and determines the GSQ packet after the GSQ packet is transmitted in step S6 until the lifetime elapses. If the MR packet designating the multicast group is not received, the entry corresponding to the multicast group is deleted from the multicast group management DB. At this time, when the process proceeds to step S9, since the lifetime is shortened, the time for waiting for reception of the MR packet is shortened. Further, when the entry is deleted from the multicast group management DB, the multicast address management unit 113 deletes the entry including the multicast MAC address of the multicast group in the deleted entry from the MAC address learning table of the L2 switch unit 12.

  When the IGMP / MLD packet analysis / transmission / reception unit 111 receives the MR packet transmitted by the IGMP / MLD client as a response to the GSQ packet transmitted in step S6, the IGMP / MLD packet analysis / transmission / reception unit 111 sets the downstream port that has received the MR packet as the IGMP / The MLD client learns as a downstream port that cannot leave at high speed. The learning mode of the downstream port is not particularly limited. For example, the port number of the downstream port that has received the MR packet after the transmission of the GSQ packet in step S6 is used as the port number of the downstream port that cannot be disconnected at high speed. It may be stored in a port storage means (not shown). In this way, since the IGMP / MLD client learns the downstream port that cannot leave at high speed, the downstream port that cannot leave at high speed can be determined. For example, when the port number of the downstream port that received the MR packet after the transmission of the GSQ packet in step S6 is stored in the high-speed leave port storage means as in the above example, the high-speed leave port storage means stores the port number. The downstream port of the port number is a port that the IGMP / MLD client cannot leave at high speed, and the other downstream ports can be determined as ports that the IGMP / MLD client can leave at high speed.

  As described above, according to the present invention, after receiving a group leaving packet, when a GSQ packet is transmitted and an MR packet is received as a response to the GSQ packet, the downstream port that has received the MR packet is It learns as a downstream port where the IGMP / MLD client cannot leave at high speed. Therefore, it is possible to determine the downstream port where the IGMP / MLD client cannot leave at high speed. Therefore, a downstream port that can turn on the Fast-Leave function (a port that the IGMP / MLD client can leave at high speed) and a downstream port that cannot turn on the Fast-Leave function (the IGMP / MLD client that uses a high speed) Since a downstream port that cannot be removed at high speed is learned, the Fast-Leave function can be appropriately set, and the IGMP / MLD client can be appropriately removed at high speed.

  Also, in the present invention, when there is one IGMP / MLD client corresponding to the downstream port that has received the group leaving packet, the corresponding entry is immediately deleted from the multicast group management DB and the MAC address learning table of the L2 switch unit 12. Therefore, the IGMP / MLD client can be disconnected at high speed (step S8).

  Even if the downstream port that leaves the IMGP / MLD client at a high speed is not learned as a downstream port that cannot leave at high speed, a group leave packet is transmitted from the upstream port in step S10. Then, at a port that has not been learned as a downstream port that cannot leave at high speed, viewing may be interrupted even though there are clients viewing the multicast group. However, in the present invention, in step S9, the lifetime of the entry corresponding to the multicast group requested to leave is shortened using the group leave packet. Accordingly, since the response (MR packet) of the GSQ packet can be received quickly, such a viewing interruption time can be shortened.

  In addition, after transmitting a GSQ packet, when an MR packet is not received before the lifetime expires, you may repeat transmitting a GSQ packet again. Then, it may be determined that there is no response from the IGMP / MLD client when the MR packet is not received for a predetermined number of times after the lifetime period elapses after the GSQ packet is transmitted. The same applies to GQ packets.

Example 2
FIG. 6 is a block diagram showing the configuration of the second embodiment of the present invention. The second embodiment shows a case where the relay device of the present invention is mounted on an IGMP / MLD proxy. Constituent elements similar to those shown in the first embodiment are denoted by the same reference numerals as in FIG. In this embodiment, a relay device (hereinafter referred to as an IGMP / MLD proxy device) 10 includes an IGMP / MLD processing unit 11a, an L2 switch unit (L2 switch unit with an IGMP / MLD snooping function) 12, and a router unit 13. With. The IGMP / MLD processing unit 11a includes an IGMP / MLD proxy processing unit 115, an IGMP / MLD client management DB unit 112, a multicast address management unit 113, and a multicast group management DB unit 114. The IGMP / MLD proxy processing unit 115 includes an IGMP / MLD packet analysis / transmission / reception unit 111.

  The L2 switch unit 12 transmits the IGMP / MLD packet received from the downstream port to the router unit 13. When receiving a packet from the IGMP / MLD processing unit 11a, the packet is received via the router unit 13. Other points are the same as those of the L2 switch unit 12 described in the first embodiment.

  The router unit 13 performs routing of multicast packets based on the multicast group management DB stored in the multicast group management DB unit 114. In addition, the router unit 13 transmits a packet addressed to the IGMP / MLD Queryer to the IGMP / MLD proxy processing unit 115. The packet addressed to the IGMP / MLD Queryer is an IMGP / MLD packet addressed to the IGMP / MLD proxy device 10. The router 13 is provided with an upstream port, and the router unit 13 transmits an IGMP / MLD packet that the IGMP / MLD processing unit 11a transfers to the upstream port side from the upstream port. Then, the packet transmitted from the IGMP / MLD processing unit 11a to the IGMP / MLD client is transmitted to the L2 switch unit 12.

  The IGMP / MLD client management DB unit 112, the multicast address management unit 113, and the multicast group management DB unit 114 are respectively the IGMP / MLD client management DB unit 112 and the multicast address management unit 113 shown in the first embodiment. This is the same as the multicast group management DB unit 114.

  In other words, the IGMP / MLD client management DB unit 112 stores an IGMP / MLD client management DB in which the port number is associated with the MAC address of the IGMP / MLD client that has transmitted the IGMP / MLD packet.

  The multicast group management DB unit 114 stores a multicast group management DB in which port numbers, multicast addresses, “Source Specific Address”, and lifetimes are associated with each other. However, when a version of IGMP / MLD other than IGMPv3 / MLDv2 is applied, “Source Specific Address” is not included in the multicast group management DB.

  In addition, the multicast address management unit 113 monitors the multicast group management DB stored in the multicast group management DB unit 114, waits for a response from the IGMP / MLD client after transmitting the GQ packet or the GSQ packet, and is determined. If an MR packet designating a multicast group is not received before the time (lifetime) elapses, the entry corresponding to the multicast group is deleted from the multicast group management DB. Further, the entry corresponding to the multicast group is deleted from the MAC address learning table (not shown) of the L2 switch unit 12.

  The IGMP / MLD proxy processing unit 115 performs IGMP / MLD proxy processing. The IGMP / MLD proxy processing by the IGMP / MLD proxy processing unit 115 is the same as the IGMP / MLD proxy processing known to those skilled in the art.

  The IGMP / MLD packet analysis / transmission / reception unit 111 provided in the IGMP / MLD proxy processing unit 115 receives the IGMP / MLD packet received from the IGMP / MLD client by the L2 switch unit 12 via the router unit 13. Then, depending on the type of the IGMP / MLD packet, addition or deletion of data regarding the multicast group to the multicast group management DB, multicast MAC address to the MAC address learning table (not shown) of the L2 switch unit 12 is performed. Perform additional registration. This operation is the same as the operation shown in FIG. However, since the router unit 13 transmits the IMGP / MLD packet addressed to the IGMP / MLD proxy device 10 to the IGMP / MLD proxy processing unit 115, the IGMP / MLD packet analysis / transmission / reception unit 111 determines that the received packet is an IMGP / MLD packet. What is necessary is just to perform the process after step S2 without determining whether it is a packet (step S1).

  However, the IGMP / MLD packet analysis / transmission / reception unit 111 terminates the received IGMP / MLD packet. The IGMP / MLD packet analysis / transmission / reception unit 111 transmits the IGMP / MLD packet via the router unit 13 on behalf of the IGMP / MLD packet analysis / transmission / reception unit 111. For example, the IGMP / MLD packet analysis / transmission / reception unit 111 terminates the received MR packet or group leaving packet. Then, the IGMP / MLD packet analysis / transmission / reception unit 111 transmits the MR packet and the group leaving packet via the router unit 13.

  According to the present embodiment, the IGMP / MLD proxy processing unit that performs IGMP / MLD processing and performs multicast group management and the IGMP / MLD packet analysis / transmission / reception unit 111 can be integrated as an original function. The MLD processing unit 11a can be easily mounted.

  The IGMP / MLD proxy processing unit 115 may be a multicast router unit.

  In the first and second embodiments, the IGMP / MLD processing units 11 and 11a are computers that can access the MAC address learning table of the L2 switch unit 12, and are IGMP / MLD client management DB units. 112 and a computer having the multicast group management DB unit 114 may be realized. In this case, the computer may read the relay program stored in the storage device in advance, and perform operations as the IGMP / MLD packet analysis / transmission / reception unit 111 and the multicast address management unit 113 according to the relay program.

  In the above embodiment, the switch unit is realized by the L2 switch unit 12, and the control unit is realized by the IGMP / MLD processing units 11 and 11a. The client management database storage unit is realized by the IGMP / MLD client management DB unit 112, and the multicast group management database storage unit is realized by the multicast group management DB unit 114. The registration means is realized by the IGMP / MLD packet analysis / transmission / reception unit 111 that executes Step S4. The inquiry means is realized by the IGMP / MLD packet analysis / transmission / reception unit 111 that executes step S6. The leaving processing means is realized by the IGMP / MLD packet analysis / transmission / reception unit 111 that executes Step S8. The learning means is realized by the IGMP / MLD packet analysis / transmission / reception unit 111.

  In addition, according to the above description, when there are a plurality of clients corresponding to the port that has received the group leaving packet, the control unit determines in advance the lifetime corresponding to the multicast group that is the target of the inquiry by the inquiry packet. Has a lifetime shortening means that shortens the requested time, and when the learning means receives the transmission request packet after transmitting the inquiry packet and before the shortened lifetime elapses, the learning means receives the transmission request packet. A configuration is disclosed in which the learned port is learned as a port that the client cannot leave at high speed.

  In addition, when the control unit receives the transmission request packet, the control unit includes a client registration unit that associates the port that has received the transmission request packet with the client that is the transmission source of the transmission request packet and registers the client registration in the client management database. It is disclosed. The client registration means is realized by the IGMP / MLD packet analysis / transmission / reception unit 111 that executes Step S3.

  Further, a configuration is disclosed in which the inquiry means transmits an inquiry packet to a client via a switch unit.

  Also, the router is used as an IGMP / MLD proxy device, and the switch unit includes a router unit that transmits a transmission request packet and a group leaving packet received from the client to the control unit, and the inquiry unit sends the inquiry packet via the router unit and the switch unit. A configuration for transmitting to a client is disclosed.

  The present invention is suitably applied to devices having an IGMP / MLD Query function, such as a multicast router, a router with an IGMP / MLD proxy function, and an L2 switch with an IGMP / MLD snooping function.

It is a block diagram which shows the example of the relay apparatus of this invention. It is a block diagram which shows the relay apparatus shown in FIG. 1 in detail. It is explanatory drawing which shows the example of multicast group management DB. It is explanatory drawing which shows the example of IGMP / MLD client management DB. 5 is a flowchart showing an example of operation of an IGMP / MLD packet analysis / transmission / reception unit 111. It is a block diagram which shows the structure of the 2nd Example of this invention. It is explanatory drawing which shows the example of a general IGMP / MLD snooping apparatus.

Explanation of symbols

1 IGMP / MLD snooping device (relay device)
11 IGMP / MLD processing unit 12 L2 switch unit with IGMP / MLD snooping function 111 IGMP / MLD packet analysis / transmission / reception unit 112 IGMP / MLD client management DB unit 113 multicast address management unit 114 multicast group management DB unit

Claims (6)

A relay device that relays multicast packets,
A plurality of ports to which clients that receive multicast packets are connected; a switch unit that holds a MAC address learning table that associates MAC addresses with ports; and
A control unit that transmits an inquiry packet for inquiring whether or not a multicast group that is a group of multicast packets has been received;
The control unit
Client management database storage means for storing a client management database in which a client that has requested transmission of a multicast group is associated with a port to which the client is connected;
Multicast group management database storing a multicast group management database in which a port to which a client that has requested transmission of a multicast group is connected, identification information of the multicast group, and a lifetime that is a time to wait for a response to an inquiry packet are associated with each other Storage means;
When a transmission request packet for requesting transmission of a multicast group is received, the port that has received the transmission request packet, identification information of the multicast group, and a lifetime determined for the multicast group are associated with each other in the multicast A registration unit that registers in the group management database and registers the multicast MAC address of the multicast group and the port that has received the transmission request packet in the MAC address learning table of the switch unit,
Inquiry means for sending an inquiry packet for inquiring whether or not the multicast group is received when a group leaving packet for requesting transmission stop of the multicast group is received;
Client number determination means for determining whether the number of clients corresponding to the port that has received the group leave packet is one or more when referring to the client management database when the group leave packet is received;
When the number of clients corresponding to the port that has received the group leave packet is one, an entry corresponding to the multicast group requested to stop transmission by the group leave packet is sent to the multicast group management database and the MAC address learning of the switch unit. Detachment processing means to be deleted from the table,
After sending an inquiry packet inquiring whether or not the inquiry means has received the multicast group, when the transmission request packet requesting transmission of the multicast group is received as a response to the inquiry packet, the transmission request packet is received. Learning means to learn the port as a port that the client cannot leave at high speed ,
A lifetime shortening means for shortening the lifetime corresponding to the multicast group to be inquired by the inquiry packet from a predetermined time when the number of clients corresponding to the port receiving the group leaving packet is plural; Have
When the learning means receives a transmission request packet after the inquiry packet is transmitted and before the shortened lifetime elapses, the learning means learns the port that has received the transmission request packet as a port that the client cannot leave at high speed. A relay device characterized by that. The control unit
The relay apparatus according to claim 1, further comprising: a client registration unit that registers a port that has received the transmission request packet and a client that has transmitted the transmission request packet in the client management database when the transmission request packet is received. . Inquiry means, a relay device according to claim 1 or claim 2 transmits the inquiry packet to the client via the switch unit. Used as an IGMP / MLD proxy device,
The switch unit includes a router unit that transmits the transmission request packet and group leaving packet received from the client to the control unit,
Inquiry means, a relay device according to claim 1 or claim 2 to the client via the router and switch unit an inquiry packet. A plurality of ports to which clients that receive multicast packets are connected are provided, a switch unit that holds a MAC address learning table that associates MAC addresses with ports, and whether a multicast group that is a group of multicast packets is received. A client management database storage unit that stores a client management database that associates a client that has requested transmission of a multicast group with a port to which the client is connected, and a control unit that transmits an inquiry packet for inquiry. , The port to which the client that requested the transmission of the multicast group is connected, the identification information of the multicast group, and the life time that is the time to wait for the response to the inquiry packet A relay method to be applied to the relay device of a multicast packet having a multicast group management database storage means for storing the multicast group management database that associates bets,
When a transmission request packet for requesting transmission of a multicast group is received, the port that has received the transmission request packet, identification information of the multicast group, and a lifetime determined for the multicast group are associated with each other in the multicast Registering in the group management database, associating the multicast MAC address of the multicast group with the port that received the transmission request packet, and registering it in the MAC address learning table of the switch unit,
When a group leaving packet requesting to stop transmission of a multicast group is received, an inquiry packet for inquiring whether or not the multicast group is received is transmitted,
When receiving a group leave packet, refer to the client management database to determine whether the number of clients corresponding to the port that received the group leave packet is one or more,
When the number of clients corresponding to the port that has received the group leave packet is one, an entry corresponding to the multicast group requested to stop transmission by the group leave packet is sent to the multicast group management database and the MAC address learning of the switch unit. Delete from the table and
When the number of clients corresponding to the port that received the group leaving packet is plural, the lifetime corresponding to the multicast group that is the inquiry target by the inquiry packet is shortened from a predetermined time,
When a transmission request packet requesting transmission of the multicast group is received as a response to the inquiry packet after transmitting an inquiry packet asking whether or not the multicast group is received before the shortened lifetime elapses In addition, the relay method is characterized in that the port that received the transmission request packet is learned as a port that the client cannot leave at high speed. Multiple ports to which clients that receive multicast packets are connected are provided, and it is possible to access the MAC address learning table of the switch unit that holds the MAC address learning table that associates the MAC address with the port, and requested transmission of the multicast group Client management database storage means for storing a client management database in which a client is associated with a port to which the client is connected; a port to which a client that has requested transmission of a multicast group is connected; identification information for the multicast group; Multicast group management data for storing a multicast group management database in association with a lifetime that is a time to wait for a response to an inquiry packet A relay program installed on a computer with an over scan memory means,
On the computer,
When a transmission request packet for requesting transmission of a multicast group is received, the port that has received the transmission request packet, identification information of the multicast group, and a lifetime determined for the multicast group are associated with each other in the multicast A registration process for registering in the group management database and associating the multicast MAC address of the multicast group with the port that received the transmission request packet in the MAC address learning table of the switch unit,
An inquiry process for transmitting an inquiry packet for inquiring whether or not the multicast group is received when a group leaving packet requesting to stop transmission of the multicast group is received;
A client number determination process for determining whether the number of clients corresponding to the port that has received the group leave packet is one or more when referring to the client management database when the group leave packet is received;
When the number of clients corresponding to the port that has received the group leave packet is one, an entry corresponding to the multicast group requested to stop transmission by the group leave packet is sent to the multicast group management database and the MAC address learning of the switch unit. Leave processing to be deleted from the table ,
Lifetime shortening processing for shortening the lifetime corresponding to the multicast group to be inquired by the inquiry packet from a predetermined time when the number of clients corresponding to the port receiving the group leaving packet is plural, and after transmitting an inquiry packet for inquiring whether it is receiving a multicast group, as a response to the inquiry packet, the transmission request packet requesting transmission of the multicast group and received before shortened lifetime has elapsed Sometimes, a relay program for executing learning processing that learns the port that received the transmission request packet as a port that the client cannot leave at high speed.

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