JP6475086B2 - Communication apparatus, relay method, validity confirmation response method, and computer program - Google Patents

Description

  The present invention relates to a communication frame relay method in a communication system.

  In a communication network in which communication frames are relayed via a plurality of relay devices, it is common for the relay device to manage a route for relaying received communication frames by learning. For example, it is known that a relay apparatus having a filtering database function compliant with IEEE 802.1D called a spanning tree protocol learns a source MAC (Media Access Control) address of a received layer 2 (L2) frame. Such a relay apparatus registers the transmission source MAC address of the received L2 frame in the filtering database (learned information) in association with the reception port that has received the frame. Then, when the destination MAC address of the L2 frame to be subsequently received is registered in the filtering database (learned), the relay device transmits the received L2 frame to the associated reception port (unicode). Cast transfer). On the other hand, when the destination MAC address of the received L2 frame is not learned, the relay device transmits the L2 frame to all ports except the port that received the L2 frame (flooding transfer). It is known that this filtering database is managed by aging monitoring in which old MAC addresses that have become invalid are periodically deleted.

  As a technique related to management of such learned information, for example, Patent Document 1 discloses a relay apparatus that updates learning information in response to a change in a communication environment. When receiving the Ethernet (registered trademark) frame, the relay device described in Patent Document 1 stores the correspondence between the transmission source MAC address and the reception port of the Ethernet frame as learning information. And this relay apparatus prevents the learning information which becomes effective after the environment change at all by receiving the learning information which becomes effective after the change of the communication environment by the encapsulated frame from the other relay apparatus. In this way, this relay apparatus can suppress the occurrence of flooding even when the communication environment changes. In addition, the learning information management unit in this relay device searches the learning table in order at regular intervals, and adds 1 to the aging value of each learned entry. The learning information management unit deletes the entry when the aging value exceeds a predetermined value as a result of the addition.

  Patent Document 2 discloses a communication method for managing a MAC address table for registering correspondence between MAC addresses and ports of a plurality of terminal devices in a network in which a plurality of bases are connected by a plurality of wide area Ethernet networks. Yes. In the communication method described in Patent Document 2, the information on the terminal of the terminal device (MAC address as the transmission source) is periodically connected to the multi-route broadcast switching hub that connects the Ethernet networks. Frame) is transmitted to another multi-route broadcast switching hub. Other multi-route broadcast switching hubs update the MAC address table with the received terminal information. In this way, the multi-path broadcast switching hub can prevent the information on the connected (valid) terminal device from being deleted from the MAC address table of the other switching hub.

JP 2012-019391 A Japanese Patent Application Laid-Open No. 2014-082803

  However, if the relay apparatus disclosed in Patent Document 1 does not receive an L2 frame with the MAC address that was the target of unicast transfer as the transmission source within the valid time, the bandwidth in all networks connected to itself There is a problem of pressure. In other words, even if a communication device having a learned (unicast transfer target) MAC address can communicate with the relay device, the communication device must perform transmission via the relay device for a certain period of time. There is a problem of flooding transfer.

  In addition, the communication method disclosed in Patent Document 2 has a problem that the multi-path broadcast switching hub constantly consumes network bandwidth by transmitting unnecessary terminal information. This is because the multi-path broadcast switching hub transmits other terminal information even when there is a frame transmitted from the terminal itself.

  One object of the present invention is to reduce the bandwidth of a network connected to another port when a communication frame whose source is an address targeted for unicast transfer is not received beyond a predetermined valid time. An object of the present invention is to provide a communication device that reduces the pressure.

  In order to achieve the above object, a first communication device according to an aspect of the present invention includes the following configuration.

That is, the first communication device according to one aspect of the present invention is provided.
Multiple ports,
After receiving the first communication frame, when the second communication frame addressed to the transmission source address of the first communication frame is received, the second communication frame is changed to the port that has received the first communication frame. Relay control means for performing unicast transfer to transmit to the receiving port,
After receiving the first communication frame, when a state in which a communication frame whose transmission source address is a transmission source has not been received exceeds a predetermined valid time, an inquiry is made as to whether communication with the transmission source address is possible. A validity inquiry means that can send a validity confirmation request to the receiving port and receive a validity confirmation response that is a response to the validity confirmation request;
In response to the validity confirmation request, the relay control means, when an validity confirmation response indicating that communication with the source address is possible is not obtained, is addressed to the source address received thereafter. A flooding transfer is performed in which the second communication frame is transmitted to each port other than the port that has received the second communication frame.

In order to achieve the above object, a relay method according to an aspect of the present invention is performed by an information processing device.
After receiving the first communication frame, when receiving the communication frame addressed to the transmission source address of the first communication frame, the second communication frame addressed to the transmission source address is received and the first communication frame is received. Unicast transfer to send to the receiving port
After receiving the first communication frame, when a state in which a communication frame whose transmission source address is a transmission source has not been received exceeds a predetermined valid time, an inquiry is made as to whether communication with the transmission source address is possible. Send a validation request to the receiving port,
In response to the validity confirmation request, if a validity confirmation response indicating that communication with the transmission source address is possible is not obtained, a second communication frame addressed to the transmission source address is received thereafter. Flooding transfer is performed in which the second communication frame is transmitted to each port other than the port that has received the second communication frame.

  Further, the object is to provide a computer program for realizing the first communication apparatus having the above-described configurations and the corresponding method by a computer, and a computer-readable storage medium storing the computer program. Is also achieved.

  The present invention has an effect of reducing the time during which flooding transfer is performed. Thus, the present invention has an effect of reducing the pressure on the network band connected to the relay device.

1 is a block diagram showing a configuration of a communication system according to a first embodiment of the present invention. It is a block diagram which shows an example of the communication environment in the communication system which concerns on 2nd and 3rd embodiment. It is a block diagram which shows the structure of the frame relay apparatus 100,110,120 which concerns on the 2nd Embodiment of this invention. It is a figure which shows an example of the relay information 104 of the frame relay apparatus 100 in 2nd Embodiment. It is a state transition diagram which shows the change of the state of the relay information 104 in 2nd Embodiment. 10 is a flowchart illustrating an operation performed by the frame relay apparatuses 100 and 110 in the second embodiment. It is a figure which shows an example of the relay information 104 of the frame relay apparatus 100 in the modification of 2nd Embodiment. It is a state transition diagram which shows the change of the state of the relay information 104 in the modification of 2nd Embodiment. It is a block diagram which shows the structure of the frame relay apparatuses 300, 310, and 320 which concern on the 3rd Embodiment of this invention. It is a figure which illustrates the structure of each computer (information processing apparatus) applicable to each embodiment of this invention, and the communication system which concerns on the modification.

  Next, embodiments of the present invention will be described in detail with reference to the drawings.

<First Embodiment>
FIG. 1 is a block diagram showing a configuration of a communication system according to the first embodiment of the present invention. Referring to FIG. 1, the communication system according to the present embodiment includes a first communication device 1 and a second communication device 10.

  The first communication device 1 and the second communication device 10 are communicably connected via a local area network (LAN) or a communication network such as the Internet (hereinafter simply referred to as a network). The first communication device 1 is a frame relay device capable of relaying communication frames related to communication performed between the second communication device 10 and other connected communication devices (not shown). And so on. The second communication device 10 can operate as a terminal device or a frame relay device that communicates with other communication devices (not shown) via the first communication device 1.

  The first communication apparatus 1 and the second communication apparatus 10 are general information processing that operates under the control of a computer program (software program) executed using a CPU (Central Processing Unit: not shown). You may comprise by an apparatus (computer). Alternatively, each unit of the first communication device 1 and the second communication device 10 may be configured by a dedicated hardware device or a logic circuit. A hardware configuration example in which the first communication device 1 and the second communication device 10 are realized by a computer will be described later with reference to FIG.

  The first communication device 1 includes a communication control unit 2, a relay control unit 3, an effectiveness inquiry unit 4, and a plurality of ports 5.

  The communication control unit 2 can communicate with the connected second communication device 10 and a communication device (not shown) via each port 5.

  When the relay control unit 3 receives the first communication frame via the communication control unit 2 and then receives the second communication frame addressed to the transmission source address of the first communication frame, the relay control unit 3 receives the second communication frame. Is transferred by unicast. Unicast transfer is a relay method in which a first communication frame is transmitted to port 5 (hereinafter referred to as “reception port”) that has received the communication frame. Further, the relay control unit 3 receives after that, when the validity inquiry unit 4 described later cannot obtain the validity confirmation response indicating that communication with the transmission source address of the first communication frame is possible. The second communication frame addressed to the source address is flooded and transferred. The flooding transfer is a relay method for transmitting the second communication frame to each port 5 other than the port 5 that has received the communication frame.

  After receiving the first communication frame, the validity inquiring unit 4 performs communication for the transmission source address when a state where the transmission source address does not receive the transmission frame that is the transmission source continues for a predetermined effective time. Send a validation request to inquire whether or not The validity inquiry unit 4 transmits a validity check request to the reception port that is the port 5 that has received the first communication frame. Further, the validity inquiry unit 4 can receive a validity confirmation response that is a response to the validity confirmation request. The validity inquiry unit 4 may notify the relay control unit 3 of the content of the received validity confirmation response and the absence of the validity confirmation response.

  The second communication device 10 includes a communication control unit 11 and an effectiveness response unit 12. In FIG. 1, the port of the second communication device 10 is omitted. The second communication device 10 may include a plurality of ports.

  The communication control unit 11 can communicate with the connected first communication device 1 and a communication device (not shown) via a port (not shown).

  The validity response unit 12 receives a validity confirmation request from the first communication device 1 via the communication control unit 11. When the validity response unit 12 recognizes at least that the communication addressed to the transmission source address that is the target of the validity confirmation request (that is, the first communication frame) is possible, the validity response unit 12 addresses the transmission source address. A validity confirmation response indicating that communication is possible is transmitted to the first communication device 1.

  Next, the operation of the present embodiment having the above-described configuration will be described in detail.

  When the relay control unit 3 of the first communication device 1 receives the first communication frame via a certain port 5 (reception port), the relay control unit 3 has a node having a transmission source address of the first communication frame (hereinafter referred to as “the first communication frame”). Recognizing that communication is possible at the end of the receiving port. Specifically, in FIG. 1, the first communication frame is a communication frame received from the second communication device 10. The first communication frame is a communication in which a communication frame received from a transmission source node other than the first communication device 1 connected to the second communication device 10 is relayed (transmitted) to the first communication device 1. It may be a frame. Alternatively, the second communication device 10 itself may be a transmission source node that has transmitted the first communication frame. Then, based on this recognition, the relay control unit 3 performs unicast transfer to the reception port (that is, the second communication device 10), which is received thereafter, and is transmitted to the transmission source address.

  After that, if the state where the communication frame is not received from the transmission source node of the first communication frame continues beyond the predetermined valid time, the transmission source node may not be able to communicate. Therefore, the validity inquiry unit 4 transmits a validity check request for inquiring whether or not communication to the transmission source address is possible to the reception port (second communication device 10).

  In the second communication device 10, the validity response unit 12 receives the validity confirmation request. The validity response unit 12 determines that the transmission source node having the transmission source address (the second communication device 10 itself or a communication device connected to the second communication device 10) can communicate, the transmission source A validity confirmation response indicating that communication addressed to the address is possible is transmitted to the first communication device 1.

  There is a possibility that the second communication device 10 can recognize that the transmission source node can communicate even if the communication frame issued by the transmission source node has not been transmitted to the first communication device 1. is there. For example, the second communication device 10 may continue to receive a communication frame issued by the transmission source node even during a predetermined valid time. When the second communication device 10 itself is a transmission source node, the second communication device 10 can naturally know that communication with the transmission source address is possible. As a specific method for determining whether or not the transmission source node can communicate, a well-known general technique can be adopted, and a detailed description thereof in this embodiment will be omitted.

  When the relay controller 3 of the first communication device 1 fails to obtain an validity confirmation response indicating that communication addressed to the transmission source address is possible via the validity inquiry unit 4, at least the reception port It is recognized that communication with the source address is no longer possible. Then, the relay control unit 3 floods and transfers each communication frame (second communication frame) received thereafter and addressed to the source address. As a result, if the transmission source node having the transmission source address is communicable at the other port 5, the second communication frame is sent to the new route via the other port 5 by flooding transfer. The source node can be reached via.

  When the validity confirmation response indicating that communication addressed to the transmission source address is possible via the validity inquiry unit 4, the relay control unit 3 does not particularly change the relay method for the transmission source address. May be. That is, since the relay control unit 3 has confirmed that communication addressed to the source address is possible by the validity confirmation response, the relay control unit 3 can continue the unicast transfer to the reception port for the source address. it can.

  In this manner, the present embodiment can reduce the possibility that flooding transfer is performed to another port 5 even though communication with a transmission source address is possible.

  As described above, the present embodiment is connected to another port 5 when a communication frame whose source is a unicast transfer target address is not received beyond a predetermined valid time. It is possible to reduce the pressure on the network bandwidth.

  The reason is that the validity inquiry unit 4 makes an inquiry as to whether or not communication to the transmission source address is possible when a state in which a communication frame whose transmission source address is the transmission source has not been received continues for a predetermined effective time. This is because a sex confirmation request is transmitted. This is because the relay control unit 3 performs flooding transfer when it is not confirmed by the validity confirmation response to the validity confirmation request that communication with the transmission source address is possible. That is, the relay control unit 3 is wasteful compared to the case where the communication frame having the address as the transmission source is not received beyond the predetermined valid time and the unicast transfer is immediately stopped and the flooding transfer is switched. It can be said that there is a low possibility of performing flooding transfer.

  In addition, the following can be considered as a modification of this embodiment.

  For example, when the validity response unit 12 of the second communication device 10 determines that the transmission source node is not communicable, it transmits an validity confirmation response indicating that communication addressed to the transmission source address is impossible. May be. Alternatively, the validity response unit 12 may indicate that communication addressed to the transmission source address is impossible by not transmitting the validity confirmation response. In this modified example, the validity inquiry unit 4 and the relay control unit 3 of the first communication device 1 receive the validity confirmation response indicating that communication is impossible, and the validity confirmation by a predetermined time. If no response is received, it is determined that the validity confirmation response indicating that communication is possible has not been obtained.

  The validity inquiry unit 4 of the first communication device 1 receives a validity confirmation response indicating that communication addressed to the transmission source address is possible, and then transmits a communication frame whose transmission source address is the transmission source. When the state of not receiving continues for a predetermined effective time, the processing subsequent to the transmission of the validity check request may be performed again.

  In addition, the communication control unit 2 of the first communication device 1 may perform flooding transfer on a communication frame addressed to a transmission source address received after transmission of the validity check request. When the communication control unit 2 obtains a validity confirmation response indicating that communication with the transmission source address is possible, the communication control unit 2 again performs unicast on the communication frame addressed to the transmission source address. Transfer may be performed. That is, in this modified example, the communication control unit 2 changes the relay method to flooding transfer at a timing when a state in which a communication frame whose transmission source address is a transmission source has not been received exceeds a predetermined valid time. Good. And the communication control part 2 may return to unicast transfer, when it can confirm that the communication with respect to a transmission source address is possible by a validity confirmation response. Also in this modified example, there is an effect that the time during which the flooding transfer is performed and the time during which the bandwidth of the network connected to another port is compressed are shortened.

<Second Embodiment>
Next, a second embodiment based on the above-described first embodiment will be described. In the following, the characteristic part according to the second embodiment will be mainly described, and the components of the second embodiment having the same configuration as the first embodiment are attached in the first embodiment. The same reference numerals as those of the reference numerals are attached, and the detailed description of the constituent elements is omitted.

  First, the configuration of this embodiment will be described below with reference to FIG. FIG. 2 is a configuration diagram illustrating an example of a communication environment in the communication system according to the second and third embodiments. Referring to FIG. 2, the communication system according to the present embodiment includes frame relay apparatuses 100, 110, and 120 (hereinafter referred to as “frame relay apparatuses 100 to 120”) and terminals 200, 210, and 220 that are connected to the frame relay apparatuses. And 230 (hereinafter referred to as “terminals 200 to 230”).

  The frame relay device 100 is communicably connected to the terminal 200, the frame relay device 110, and the frame relay device 120. In addition to the frame relay device 100, the frame relay device 110 is communicably connected to the terminals 210 and 230. In addition to the frame relay device 100, the frame relay device 120 is communicably connected to the terminal 220. The frame relay apparatuses 100 to 120 and the terminals 200 to 230 are connected as described above via a local area network or a communication network such as the Internet.

  The frame relay devices 100 to 120 can relay a communication frame related to communication performed between two devices connected to each other. For example, the terminal 200 can communicate with the terminal 210 via the frame relay device 100 and the frame relay device 110. In addition, the terminal 200 can communicate with the terminal 220 via the frame relay device 100 and the frame relay device 120. The terminal 210 can communicate with the terminal 220 via the frame relay device 110 and the frame relay device 120.

  The frame relay apparatuses 100 to 120 and the terminals 200 to 230 may be configured by a general information processing apparatus (computer) that operates under the control of a computer program (software program) executed using a CPU. Or each part of the frame relay apparatus 100-120 and the terminals 200-230 may be comprised by a dedicated hardware device or a logic circuit. A hardware configuration example in which the frame relay apparatuses 100 to 120 and the terminals 200 to 230 are realized by a computer will be described later with reference to FIG.

  FIG. 3 is a block diagram showing the configuration of the frame relay devices 100, 110, and 120 according to the second embodiment of the present invention. Each of the frame relay devices 100 to 120 includes a communication control unit 2, a relay control unit 3, a validity inquiry unit 4, a plurality of ports 5, and a validity response unit 12. As a specific example, the relay control unit 3 in the present embodiment includes a relay information management unit 101, a relay unit 102, and a storage device 103 that can store the relay information 104. The storage device 103 is realized by, for example, a semiconductor memory device or a disk device.

  The communication control unit 2, the relay control unit 3, the validity inquiry unit 4, the plurality of ports 5, and the validity response unit 12 in the present embodiment are basically based on the respective configurations given the same reference numerals in the first embodiment. To do. In the present embodiment, the frame relay devices 100 to 120 are based on the first communication device 1 and the second communication device 10 in the first embodiment. The frame relay devices 100 to 120 can each operate as the first communication device 1 or the second communication device 10 in the first embodiment. The relay control unit 3 according to the present embodiment is different from the first embodiment described above in that the correspondence between the transmission source MAC address and the port 5 is stored as the relay information 104 by the learning described in the background art column. . The frame relay apparatuses 100 to 120 in the present embodiment, based on the relay information 104, transfer of communication frames and the validity of addresses realized by the first communication apparatus 1 and the second communication apparatus 10 in the first embodiment. Realize each function such as management. The “MAC address” in the present embodiment is a specific example based on the address in the first embodiment.

  Since the configurations and functions of the communication control unit 2 and the port 5 in the present embodiment are the same as those in the first embodiment, a detailed description thereof is omitted.

  The relay information 104 is generated and managed by the relay information management unit 101. The relay information 104 is information stored in the storage device 103. The relay information 104 is an example of learning information described above as a filtering database in the background art column. The relay information 104 includes a plurality of MAC address entries (also simply referred to as “address entries”). Each MAC address entry includes at least columns of “MAC address”, “port number”, and “status”. The relay information 104 in the present embodiment further includes a “VLANID (Virtual LAN Identifier)” column.

  The “MAC address” column includes MAC address information. The “port number” column is the port 5 where the communication frame having the transmission source address as the MAC address information (hereinafter referred to as “corresponding MAC address”) stored in the associated “MAC address” column is received. The port number information indicating is included. The “VLANID” column includes VLANID information indicating the ID of the VLAN with which the corresponding MAC address is associated. The “status” column includes status information indicating the status related to the validity of the corresponding MAC address. In the present embodiment, status information includes “valid” and “under confirmation” as an example. “Valid” indicates that communication with the corresponding MAC address is possible. “Checking” represents waiting for a response to a validity check request for inquiring whether communication with the corresponding MAC address is possible.

  Note that the effects of this embodiment can be realized even when the relay information 104 does not include VLANID information. In the filtering database, the MAC address information and the VLAN ID information are generally managed by a combined unit. The present embodiment is a specific example realized as a form in which a “status” column is added to the general filtering database.

  In this embodiment, MAC address information is always handled as information combined with VLANID information. The same MAC address information combined with different VLANID information is individually handled as different information. In the following description, descriptions of “VLANID” and “VLANID information” are omitted. That is, the description “MAC address” or “MAC address information” can be read as the description “combination of MAC address and VLANID” or “information combining MAC address information and VLANID information”. For example, when “source MAC address information is acquired from a communication frame”, it can be read as “VLANID information combined with source MAC address information is also acquired from the communication frame”.

  The function of the relay control unit 3 in the present embodiment is realized by the relay information management unit 101 and the relay unit 102 performing a cooperative operation via the relay information 104 stored in the storage device 103. That is, when the first communication frame is received, the relay information management unit 101 associates the transmission source address of the first communication frame with the port 5 (reception port) that has received the first communication frame. The entry is registered in the relay information 104. Then, the relay information management unit 101 manages the MAC address entry according to a certain degree (effectiveness) of communication addressed to the registered transmission source address.

  The relay unit 102 relays the received communication frame (unicast transfer or flooding transfer) based on the MAC address entry of the relay information 104 managed by the relay information management unit 101.

  In addition, the relay information management unit 101 performs aging monitoring on the transmission source MAC address (MAC address entry) registered in the relay information 104. Aging monitoring is to monitor whether a communication frame with the same source address is received again within a predetermined valid time. When the relay information management unit 101 does not receive a communication frame having a transmission source address registered as a valid MAC address entry as a transmission source beyond a predetermined valid time (aging monitoring has timed out), the validity inquiry unit 4 is instructed to perform the validity check. Further, the relay information management unit 101 obtains the content of the validity confirmation response from the validity inquiry unit 4.

  Since the configuration and functions of the relay control unit 3 in the present embodiment other than those described above are the same as those of the relay control unit 3 in the first embodiment, a detailed description thereof is omitted.

  As described above, the validity inquiry unit 4 transmits a validity confirmation request based on an instruction from the relay information management unit 101. When the validity confirmation response is received, the validity inquiry unit 4 notifies the relay information management unit 101 of the content of the validity confirmation response. Since the configuration and functions other than those described above of the validity inquiry unit 4 in the present embodiment are the same as those of the validity inquiry unit 4 in the first embodiment, a detailed description thereof will be omitted.

  The validity response unit 12 receives the validity confirmation from the other frame relay apparatuses 100 to 120 via the communication control unit 2. Further, the validity response unit 12 determines whether or not communication addressed to the transmission source address that is the target of the validity confirmation request is possible by searching the relay information 104 via the relay information management unit 101. be able to. Since the configuration and functions of the validity response unit 12 in the present embodiment other than those described above are the same as those of the validity response unit 12 in the first embodiment, a detailed description thereof is omitted.

  Next, the operation of the present embodiment having the above-described configuration will be described in detail. As described above, each of the frame relay devices 100 to 120 has the same configuration and function. Hereinafter, as an example, an operation when the frame relay apparatus 100 relays a communication frame between the terminal 200 and the terminal 210 via the frame relay apparatus 110 will be described. FIG. 6 is a flowchart illustrating an operation performed by the frame relay apparatuses 100 and 110 in the second embodiment.

  In the specific example described below, it is assumed that the MAC address information of the terminals 200 and 210 is “a1” and “a2”, respectively. In frame relay apparatus 100, it is assumed that the port numbers of ports 5 connected to terminal 200, frame relay apparatus 110, and frame relay apparatus 120 are “110”, “111”, and “112”. . It is assumed that the VLAN ID of the VLAN to which the terminals 200 and 210 belong is “4000”.

  For example, the frame relay device 100 receives a communication frame (first communication frame) transmitted from the terminal 210 to the terminal 200 via the frame relay device 110 for the first time. Then, in the frame relay device 100, the relay information management unit 101 receives the first communication frame via the communication control unit 2. Then, the relay information management unit 101 registers the transmission source MAC address of the received communication frame in the relay information 104 as a valid MAC address entry (step A100).

  With reference to FIG. 5, the details of the operation when the relay information management unit 101 manages the state of each MAC address will be described. FIG. 5 is a state transition diagram showing a change in the state of the relay information 104 in the second embodiment. In FIG. 5, a “no entry” state S1, a “valid” state S2, and a “confirming” state S3 indicate management states relating to the validity of a MAC address entry for a certain MAC address. In the following, for example, the state S1 of “no entry” is described as “no entry (S1) state”.

  The no entry (S1) state indicates that the MAC address entry including the MAC address information is not registered in the relay information 104 (hereinafter referred to as “MAC address is not registered in the relay information 104”). Represent. The valid (S2) state indicates that the MAC address entry including the MAC address information is registered in the relay information 104 and is in a valid state. The valid state is a state in which a communication frame having the MAC address as a transmission source address is received within a predetermined valid time. The in-confirmation (S3) state indicates that a predetermined valid time has been exceeded since the communication frame having the MAC address as the transmission source address was last received. This checking (S3) state is also a state waiting for transmission of a validity check request for inquiring whether or not communication with the MAC address is possible and for a response to the validity check request.

  In step A100, when receiving the first communication frame transmitted from the terminal 210, the relay information management unit 101 searches the relay information 104 based on the transmission source MAC address. When the transmission source MAC address is not registered in the relay information 104 (there is no entry (S1) state), the relay information management unit 101 sets the MAC address entry for the transmission source MAC address to a valid (S2) state. And registered in the relay information 104. FIG. 4 is a diagram illustrating an example of the relay information 104 of the frame relay device 100 according to the second embodiment. Specifically, the relay information management unit 101 sets the “MAC address” field, the “port number” field, the “VLANID” field, and the “status” field to “a2”, “111”, “4000”, and “valid”, respectively. The MAC address entry (second line in FIG. 4) including information regarding the terminal 210 that is the transmission source is registered. By registering such a MAC address entry, the state of the MAC address “a2” of the terminal 210 changes from the no entry (S1) state to the valid (S2) state (C1 in FIG. 5).

  When the relay unit 102 receives a communication frame addressed to the terminal 210 (MAC address “a2”) in this state, the relay unit 102 unicast-transfers the received communication frame based on the valid (S2) state MAC address entry. be able to. For example, when receiving a communication frame addressed to the terminal 210 from the terminal 200, the relay unit 102 converts the communication frame to the port number “111” based on the “port number” field corresponding to the MAC address “a2” of the relay information 104. ”To port 5.

  Note that the relay unit 102 transfers the first communication frame received in step A100 based on the relay information 104 at the time of reception. When the MAC address “a1” of the terminal 200 that is the destination of the first communication frame is in the no entry (S1) state (no MAC address entry), the relay unit 102 receives the received port 5 (port number “111”). ) Are transferred to all the ports 5 (port numbers “110” and “111”) (flooding transfer). As shown in the first line of FIG. 7, in the valid (S2) state, the relay unit 102 receives the received communication frame for the port 5 whose port number is “110” based on the corresponding MAC address entry. Is transferred (unicast transfer).

  Next, the relay information management unit 101 performs aging monitoring on the transmission source MAC address registered as the valid (S2) state (step A101). As described above, aging monitoring is to monitor whether or not a communication frame with the same source address is received again within a predetermined effective time.

  When the relay information management unit 101 receives again the communication frame of the source MAC address “a2” subject to aging monitoring within a predetermined valid time (NO in step A102), the validity of the MAC address is continued. (C2 in FIG. 5). Then, the relay information management unit 101 starts again aging monitoring for the MAC address, starting from when the communication frame is received again (step A101).

  On the other hand, when the communication frame of the source MAC address “a2” subject to aging monitoring has not been received again (timed out) after a predetermined valid time (YES in step A102), the relay information management unit 101 Recognize that the valid time has expired due to address aging monitoring. Then, the relay information management unit 101 sets the “status” column of the MAC address entry for the source MAC address “a2” to “confirming” (step A103). In this way, the state of the MAC address “a2” of the terminal 210 transitions from the valid (S2) state to the confirming (S3) state (C3 in FIG. 5).

  Next, the relay information management unit 101 instructs the validity inquiring unit 4 to perform validity checking on the MAC address “a2” that has been checked (S3) in step A103. The validity inquiry unit 4 transmits a validity check request for inquiring whether or not communication with the MAC address “a2” is possible (step A104). Specifically, the relay information management unit 101 notifies the validity inquiry unit 4 of the MAC address information “a2” together with the port number information and VLAN ID information corresponding to the MAC address “a2”. To do. The validity inquiry unit 4 transmits a validity check request including “a2” as the MAC address information and “4000” as the VLANID information from the port 5 of the notified port number “111”.

  The transmitted validity check request is sent to the frame relay apparatus 110 connected via the port 5 with the port number “111”. In the frame relay device 110, the validity response unit 12 receives a validity check request for the MAC address “a2” via the communication control unit 2 (step B110).

  The validity response unit 12 of the frame relay apparatus 110 confirms the validity of the MAC address “a2” designated as the target of the validity confirmation request (step B111). In this embodiment, also in the frame relay device 110, the relay information management unit 101 generates and manages the relay information 104. As one specific example, the validity response unit 12 confirms the validity of the MAC address based on the relay information 104 in the frame relay apparatus 110. For example, the validity response unit 12 may determine that the MAC address “a2” is valid (communicable) when the MAC address “a2” is present in the relay information 104 (FIG. 5). . Alternatively, the validity response unit 12 determines that the MAC address “a2” is valid when there is a MAC address entry whose status column is “valid” for the MAC address “a2” in the relay information 104. May be.

  The validity response unit 12 transmits an validity confirmation response indicating the validity of the MAC address “a2” that is the target of the validity confirmation request to the transmission source of the validity confirmation request (step B112). That is, when the MAC address “a2” is valid, the validity response unit 12 sends an validity confirmation response indicating that the MAC address “a2” is valid (communication is possible) to the frame relay apparatus 100. To send. When the MAC address “a2” is not valid, the validity response unit 12 sends an validity confirmation response indicating that the MAC address “a2” is not valid (communication is impossible) to the frame relay apparatus 100. May be transmitted. Alternatively, the validity response unit 12 may indicate that the MAC address “a2” is not valid by not sending a validity confirmation response.

  In the frame relay device 100, the validity inquiry unit 4 receives the validity confirmation response via the communication control unit 2 (step A105). The validity inquiry unit 4 notifies the relay information management unit 101 of the content of the received validity confirmation response. In addition, the validity inquiry unit 4 relays that the MAC address is not valid as the contents of the validity confirmation response when the validity confirmation response is not received within a predetermined time after transmitting the validity confirmation request. You may notify with respect to the information management part 101. FIG.

  When the content of the validity confirmation response notified from the validity inquiry unit 4 is “communication addressed to the address to be confirmed is possible” (YES in step A106), the relay information management unit 101 determines that the MAC address “a2”. Is recognized as valid. Then, the relay information management unit 101 sets “valid” in the “status” column of the MAC address entry for the MAC address “a2” (step A107). In this way, the state of the MAC address “a2” of the terminal 210 transitions from the confirming (S3) state to the valid (S2) state (C4 in FIG. 5). That is, the relay unit 102 can continuously unicast the communication frame addressed to the MAC address “a2” (terminal 210) without performing flooding transfer even after aging monitoring times out (YES in step A102). .

  On the other hand, if the content of the validity confirmation response notified from the validity inquiry unit 4 is not “communication to the address to be confirmed is possible” (NO in step A106), the relay information management unit 101 determines that the MAC address “a2 Is recognized as unnecessary. Then, the relay information management unit 101 deletes the MAC address entry for the MAC address “a2” from the relay information 104 (step A120). In this way, the state of the MAC address “a2” of the terminal 210 transitions from the confirming (S3) state to the no entry (S1) state (C5 in FIG. 5).

  Thereafter, when receiving a communication frame addressed to the MAC address “a2” (terminal 210), the relay unit 102 searches the relay information 104 to recognize that there is no entry (S1). Then, the relay unit 102 performs flooding transfer to all the ports 5 other than the port (port number “111”) that has received the communication frame.

  In this way, the frame relay device 100 can reduce the possibility that a communication frame addressed to the MAC address is flooded and transferred even though communication to the MAC address is possible.

  The reason is that, when the validity inquiry unit 4 of the frame relay device 100 times out the aging monitoring for the MAC address, the validity of the MAC address “a2” is sent to the frame relay device 110 closer to the terminal 210 having the MAC address. This is because sex is inquired. When the relay information management unit 101 receives a response from the frame relay device 110 that the MAC address “a2” is valid (communicable), the MAC address “a2” is not deleted from the relay information 104. It is.

  Even when the aging monitoring for the MAC address “a2” has timed out in the frame relay device 100, the MAC address “a2” may still be valid (S2) in the frame relay device 110. This is because, for example, the frame relay apparatus 110 may transfer a communication frame transmitted from the terminal 210 to the terminal 230 or the like during aging monitoring of the frame relay apparatus 100. That is, the frame relay device 110 is more likely to accurately grasp the validity of the MAC address of the terminal 210 than the frame relay device 100 far from the terminal 210 having the MAC address. Accordingly, the frame relay device 100 makes an inquiry about the validity of the MAC address to the frame relay device 110 having more accurate information, thereby reducing the fact that the communication frame for the communicable MAC address is flooded and transferred. I can expect that.

As described above, in the present embodiment, as in the first embodiment described above, a communication frame having a transmission source of an address that is a target of unicast transfer is received beyond a predetermined valid time. In the case where there is not, there is an effect that it is possible to reduce the pressure of the network band connected to the other port 5 being compressed.
(Modification of the second embodiment)
In addition, the following can be considered as a modification of this embodiment.

  For example, the relay control unit 3 may check the validity of the MAC address based on conditions other than the timeout of aging monitoring. As an example of such a condition, the relay control unit 3 can perform validity confirmation based on the number of times a communication frame addressed to the MAC address being confirmed (S3) is received. In this case, for example, the hit number information may be added to each MAC address entry of the relay information 104 for management. The hit number information is information representing the value (number of hits) of the number of times a communication frame addressed to the MAC address being confirmed (S3) is received during a predetermined period. FIG. 7 is a diagram illustrating an example of the relay information 104 of the frame relay device 100 according to the modification of the second embodiment.

  Referring to FIG. 7, the present modification is different from the second embodiment in that a “number of hits” field is added to each MAC address entry. When the relay information management unit 101 changes the state of a certain MAC address from the valid (S2) state to the confirming (S3) state in step A103, the relay information management unit 101 displays the hit number information included in the MAC address entry for the MAC address as “ Initially set to “0”. Then, the relay information management unit 101 refrains from the validity inquiry unit 4 for performing the validity check. In other words, in the present modification, the operation of sending the validity confirmation request (step A104) is not performed immediately after the transition to the confirmation (S3).

  The relay information management unit 101 increments the value of the hit number information by one each time a communication frame having the MAC address as a transmission source is received in a predetermined period after the transition to the confirming (S3) state. That is, the state of the MAC address remains in the confirmation state (S3) (C6 in FIG. 8). FIG. 8 is a state transition diagram illustrating a change in the state of the relay information 104 in the modification of the second embodiment. Then, when the value of the hit number information reaches a predetermined threshold value, the relay information management unit 101 instructs the validity inquiry unit 4 to perform validity confirmation on the MAC address. In response to the instruction, the validity inquiry unit 4 transmits a validity confirmation request to the port 5 that has received the communication frame having the MAC address as the transmission source address (step A104). Since the operation of each part in the present modification is the same as that of the second embodiment except for the above, overlapping description is omitted.

  In this way, the relay information management unit 101 in the present modification extracts a MAC address having a large number of communication frames (with a large number of hits) destined for the MAC address from among the MAC addresses for which aging monitoring has timed out, Validity queries can be made. In other words, the present modification has an effect of reducing the number of times of inquiries about validity for the MAC address while maintaining the effect of the second embodiment to some extent. Therefore, it is possible to reduce the load on the frame relay apparatus 110 and the like that receives the validity check request.

<Third Embodiment>
Next, a third embodiment based on the above-described second embodiment will be described. In the following, characteristic parts according to the third embodiment will be mainly described, and components of the third embodiment having the same configuration as the second embodiment will be attached in the second embodiment. The same reference numerals as those of the reference numerals are attached, and the detailed description of the constituent elements is omitted.

  First, the configuration of this embodiment will be described below with reference to FIGS. FIG. 9 is a block diagram showing a configuration of frame relay apparatuses 300, 310, and 320 according to the third embodiment of the present invention. The communication system according to the present embodiment includes frame relay apparatuses 300, 310, and 320 (hereinafter referred to as “frame relay apparatuses 300 to 320”) and terminals 200 to 230 connected to the respective frame relay apparatuses. The connection relationship and hardware configuration of each device included in the communication system according to the present embodiment can be obtained by replacing the “frame relay devices 100 to 120” with “frame relay devices 300 to 320”. Since it is the same as that of a form, the detailed description which overlaps is abbreviate | omitted.

  Referring to FIG. 9, the frame relay apparatuses 300 to 320 according to the present embodiment are added to the communication control unit 2, the relay control unit 3, the validity inquiry unit 4, the plurality of ports 5, and the validity response unit 12, respectively. And a storage device 301 capable of storing the validity setting information 302. The storage device 301 is realized by, for example, a semiconductor memory device or a disk device. The storage device 301 and the storage device 103 may be the same device.

  This embodiment is different from the second embodiment in that the validity setting information 302 and the storage device 301 are included. The validity setting information 302 includes information representing a setting relating to validity (that communication is possible) of the MAC address. For example, the validity setting information 302 may hold MAC address information, VLAN ID information, and valid or invalid information. The validity setting information 302 may be registered in advance with the frame relay apparatuses 300 to 320 by a maintenance person, for example.

  Components other than the storage device 301 and the validity setting information 302 (the communication control unit 2, the relay control unit 3, the validity inquiry unit 4, the plurality of ports 5, and the validity response unit 12) are the same as those in the second embodiment. Basic. The operation of the constituent elements based on the second embodiment described above is based on the operation of each constituent element of the second embodiment shown in FIG. Below, the characteristic part which concerns on this embodiment is demonstrated, and the overlapping description regarding the structure and operation | movement similar to 2nd Embodiment is abbreviate | omitted.

  In the present embodiment, the validity of the MAC address (and VLANID) can be determined based on the validity setting information 302. For example, when the validity response unit 12 confirms the validity of the MAC address (and VLANID) specified in the validity confirmation request in Step B111 of FIG. Therefore, it may be determined that it is valid or invalid (not valid).

  Or the relay information management part 101 does not need to perform the operation | movement after aging monitoring (step A101) with respect to the MAC address (and VLANID) registered into the validity setting information 302. FIG. For example, for the MAC address (and VLANID) registered in the validity setting information 302, the relay information management unit 101 always changes the validity (S2) state or entry according to the contents registered in the validity setting information 302. It may be handled as a state of no (S1).

  In this way, this embodiment can further improve the same effect as the second embodiment. For example, if information indicating that a certain MAC address is always valid is registered in the validity setting information 302, there is an effect that flooding transfer is not performed on the communicable MAC address. On the other hand, if information indicating that a certain MAC address is invalid is registered in the validity setting information 302, the load on the validity confirmation response unit 12 is reduced. In addition, there is an effect that the time until the validity confirmation response is returned is shortened. In addition to these, there is an effect that the load of the validity inquiry process for the MAC address registered in the validity setting information 302 is reduced.

  Note that only one of the operations of the validity response unit 12 and the relay information management unit 101 described above may be performed.

  1 to 3 and 9 in each of the above-described embodiments may be configured by independent hardware circuits, or a function (processing) unit (software module) of a software program. Can be caught. However, the division of each part shown in these drawings is a configuration for convenience of explanation, and various configurations can be assumed for mounting. An example of the hardware environment in such a case will be described with reference to FIG.

  FIG. 10 is a diagram illustrating the configuration of a computer (information processing apparatus) applicable to the communication system according to each embodiment of the present invention and its modification. That is, FIG. 10 shows the first communication device 1, the second communication device 10, the frame relay device 100, 110, 120, 300, 310 and 320 or the terminals 200, 210, 220 and The configuration of a computer capable of realizing at least any one of 230, showing a hardware environment capable of realizing each function in each of the above-described embodiments.

  A computer 900 illustrated in FIG. 10 includes a CPU (Central Processing Unit) 901, a ROM (Read Only Memory) 902, a RAM (Random Access Memory) 903, a communication interface (IF) 904, a display 905, and a hard disk device (HDD) 906. These are connected via a bus 907. 10 functions as the first communication device 1, the second communication device 10, the frame relay devices 100, 110, 120, 300, 310, and 320, or the terminals 200, 210, 220, and 230. When doing so, the display 905 need not always be provided.

  The communication interface 904 is a general communication unit that realizes communication between the computers in each of the above-described embodiments. The hard disk device 906 stores a program group 906A and various storage information 906B. The program group 906A is, for example, a computer program for realizing a function corresponding to each block (each unit) illustrated in FIGS. 1 to 3 and FIG. 9 described above. The various storage information 906B is, for example, the relay information 104 and the validity setting information 302 shown in FIGS. In such a hardware configuration, the CPU 901 governs the overall operation of the computer 900.

  The present invention described by taking each of the above embodiments as an example is a computer capable of realizing the functions of the block configuration diagrams (FIGS. 1 to 3 and FIG. 9) or the flowchart (FIG. 6) referred to in the description of each embodiment. After the program is supplied, the computer program is read out and executed by the CPU 901 of the hardware. The computer program supplied to the computer may be stored in a nonvolatile storage device (storage medium) such as the RAM 903 or the hard disk device 906 which is a readable / writable temporary storage memory.

  In the above-described case, the computer program can be supplied to each device by a method of installing in the device via various recording media such as a floppy disk (registered trademark) and CD-ROM, the Internet, etc. Currently, a general procedure can be employed, such as a method of downloading from the outside via the communication network 1000. In such a case, the present invention can be understood to be configured by a computer-readable storage medium in which the code constituting the computer program or the code is recorded.

  Note that a part or all of the above-described embodiment can be described as the following supplementary notes, but is not limited to the following supplementary notes.

(Appendix 1)
Multiple ports,
After receiving the first communication frame, when the second communication frame addressed to the transmission source address of the first communication frame is received, the second communication frame is changed to the port that has received the first communication frame. Relay control means for performing unicast transfer to transmit to the receiving port,
After receiving the first communication frame, when a state in which a communication frame whose transmission source address is a transmission source has not been received exceeds a predetermined valid time, an inquiry is made as to whether communication with the transmission source address is possible. A validity inquiry means that can send a validity confirmation request to the receiving port and receive a validity confirmation response that is a response to the validity confirmation request;
In response to the validity check request, the relay control unit receives the second communication frame received after that when the validity check response indicating that communication with the source address is possible is not obtained. A first communication device that performs flooding transfer to transmit to each of the ports other than the port that received the second communication frame.

(Appendix 2)
The relay control means includes
Performing the flooding transfer on a communication frame addressed to the source address received after transmission of the validity check request,
When a validity confirmation response indicating that communication with the transmission source address is possible is obtained, the unicast transfer is performed again for a communication frame addressed to the transmission source address received thereafter. 1st communication apparatus.

(Appendix 3)
The relay control means includes
When receiving the first communication frame, at least address information indicating the transmission source address of the first communication frame, port information indicating the reception port, and state information indicating a state relating to the validity of the transmission source address Generate relay information including address entries including
When the validity confirmation response indicating that communication with the source address is possible is not obtained, the address entry for the source address is deleted from the relay information,
The first communication device according to appendix 1 or 2, wherein the unicast transfer or the flooding transfer is performed based on the address entry.

(Appendix 4)
The validity inquiry means is the number of times that a communication frame addressed to the source address is received in a predetermined period after a state in which a communication frame whose source address is the source is not received exceeds a predetermined valid time. The first communication device according to any one of appendices 1 to 3, wherein the validity check request is transmitted based on hit number information representing a value of.

(Appendix 5)
When the validity check request is received from the first communication device according to appendices 1 to 4, and when at least the communication addressed to the source address is recognized, the communication addressed to the source address is possible A second communication device including validity response means for transmitting to the first communication device a validity confirmation response indicating that

(Appendix 6)
After receiving the first communication frame, when receiving the communication frame addressed to the transmission source address of the first communication frame, the second communication frame addressed to the transmission source address is received and the first communication frame is received. Unicast transfer to send to the receiving port
After receiving the first communication frame, when a state in which a communication frame whose transmission source address is a transmission source has not been received exceeds a predetermined valid time, an inquiry is made as to whether communication with the transmission source address is possible. Send a validation request to the receiving port,
In response to the validity confirmation request, if a validity confirmation response indicating that communication with the transmission source address is possible is not obtained, a second communication frame addressed to the transmission source address is received thereafter. A relay method that performs flooding transfer in which the second communication frame is transmitted to each port other than the port that received the second communication frame.

(Appendix 7)
Performing the flooding transfer on a communication frame addressed to the source address received after transmission of the validity check request,
When a validity confirmation response indicating that communication with the source address is possible is obtained, the unicast transfer is performed again for a communication frame addressed to the source address received thereafter. Relay method.

(Appendix 8)
When receiving the first communication frame, at least address information indicating the transmission source address of the first communication frame, port information indicating the reception port, and state information indicating a state relating to the validity of the transmission source address Generate relay information including address entries including
When the validity confirmation response indicating that communication with the source address is possible is not obtained, the address entry for the source address is deleted from the relay information,
The relay method according to appendix 6 or 7, wherein the unicast transfer or the flooding transfer is performed based on the address entry.

(Appendix 9)
Number-of-hits information representing the value of the number of times a communication frame addressed to the source address is received in a predetermined period when a state in which a communication frame whose source address is the source is not received exceeds a predetermined valid time The relay method according to any one of appendices 6 to 8, wherein the validity check request is transmitted based on the following.

(Appendix 10)
Receiving the validity check request transmitted in the relay method of any one of appendices 6 to 8,
At least, when recognizing that communication addressed to the transmission source address is possible, a validity confirmation response indicating that communication addressed to the transmission source address is possible is sent to the transmission source of the validity confirmation request. Send Validity confirmation method.

(Appendix 11)
After receiving the first communication frame, when the second communication frame addressed to the transmission source address of the first communication frame is received, the second communication frame is changed to the port that has received the first communication frame. Relay control processing for performing unicast transfer to be transmitted to the receiving port,
After receiving the first communication frame, when a state in which a communication frame whose transmission source address is a transmission source has not been received exceeds a predetermined valid time, an inquiry is made as to whether communication with the transmission source address is possible. A first computer program that transmits a validity check request to the reception port and causes a computer to execute a validity inquiry process capable of receiving a validity check response that is a response to the validity check request. ,
In the relay control process,
In response to the validity confirmation request, if a validity confirmation response indicating that communication with the transmission source address is possible is not obtained, a second communication frame addressed to the transmission source address is received thereafter. A first computer program that performs flooding transfer in which the second communication frame is transmitted to each port other than the port that received the second communication frame.

(Appendix 12)
In the relay control process,
Performing the flooding transfer on a communication frame addressed to the source address received after transmission of the validity check request,
When the validity confirmation response indicating that communication with the transmission source address is possible is obtained, the unicast transfer is performed again for a communication frame addressed to the transmission source address received thereafter. The first computer program.

(Appendix 13)
In the relay control process,
When receiving the first communication frame, at least address information indicating the transmission source address of the first communication frame, port information indicating the reception port, and state information indicating a state relating to the validity of the transmission source address Generate relay information including address entries including
When the validity confirmation response indicating that communication with the source address is possible is not obtained, the address entry for the source address is deleted from the relay information,
The first computer program according to claim 11 or 12, wherein the unicast transfer or the flooding transfer is performed based on the address entry.

(Appendix 14)
In the validity query process,
Number-of-hits information representing the value of the number of times a communication frame addressed to the source address is received in a predetermined period after a state in which a communication frame whose source address is the source is not received exceeds a predetermined valid time The first computer program according to any one of appendices 11 to 13, wherein the validity check request is transmitted based on

(Appendix 15)
Receiving the validity check request described in appendices 11 to 14,
When it is recognized that communication addressed to the transmission source address is possible, a validity confirmation response indicating that communication addressed to the transmission source address is possible is transmitted to the first communication device. A second computer program causing a computer to execute validity response processing.

DESCRIPTION OF SYMBOLS 1 1st communication apparatus 2, 11 Communication control part 3 Relay control part 4 Effectiveness inquiry part 5 Port 10 2nd communication apparatus 12 Effectiveness response part 100,110,120,300,310,320 Frame relay apparatus 101 Relay Information management unit 102 Relay unit 103, 301 Storage device 104 Relay information 200, 210, 220, 230 Terminal 302 Validity setting information C1-C6 State transition S1-S3 State 900 Information processing device (computer)
901 CPU
902 ROM
903 RAM
904 Communication interface (IF)
905 Display 906 Hard disk device (HDD)
906A Program group 906B Various stored information 907 Bus 1000 Network (communication network)

Claims (10)

Multiple ports,
After receiving the first communication frame, when the second communication frame addressed to the transmission source address of the first communication frame is received, the second communication frame is changed to the port that has received the first communication frame. Relay control means for performing unicast transfer to transmit to the receiving port,
After receiving the first communication frame, when a state in which a communication frame whose transmission source address is a transmission source has not been received exceeds a predetermined valid time, an inquiry is made as to whether communication with the transmission source address is possible. A validity inquiry means that can send a validity confirmation request to the receiving port and receive a validity confirmation response that is a response to the validity confirmation request;
In response to the validity confirmation request, the relay control means, when an validity confirmation response indicating that communication with the source address is possible is not obtained, is addressed to the source address received thereafter. A first communication device that performs flooding transfer in which a second communication frame is transmitted to each port other than the port that has received the second communication frame. The relay control means includes
Performing the flooding transfer on a communication frame addressed to the source address received after transmission of the validity check request,
The unicast transfer is performed again for a communication frame addressed to the source address received after that when a validity confirmation response indicating that communication with the source address is possible is obtained. 1st communication apparatus of description. The relay control means includes
When receiving the first communication frame, at least address information indicating the transmission source address of the first communication frame, port information indicating the reception port, and state information indicating a state relating to the validity of the transmission source address Generate relay information including address entries including
When the validity confirmation response indicating that communication with the source address is possible is not obtained, the address entry for the source address is deleted from the relay information,
The first communication device according to claim 1, wherein the unicast transfer or the flooding transfer is performed based on the address entry. The validity inquiry means is the number of times that a communication frame addressed to the source address is received in a predetermined period after a state in which a communication frame whose source address is the source is not received exceeds a predetermined valid time. The first communication device according to any one of claims 1 to 3, wherein the validity check request is transmitted based on hit number information representing a value of. When receiving the validity check request from the first communication device according to claim 1 and recognizing at least that communication addressed to the source address is possible, communication addressed to the source address is performed. A second communication device including validity response means for transmitting a validity confirmation response indicating that it is possible to the first communication device. After receiving the first communication frame, when receiving the communication frame addressed to the transmission source address of the first communication frame, the second communication frame addressed to the transmission source address is received and the first communication frame is received. Unicast transfer to send to the receiving port
After receiving the first communication frame, when a state in which a communication frame whose transmission source address is a transmission source has not been received exceeds a predetermined valid time, an inquiry is made as to whether communication with the transmission source address is possible. Send a validation request to the receiving port,
In response to the validity confirmation request, if a validity confirmation response indicating that communication with the transmission source address is possible is not obtained, a second communication frame addressed to the transmission source address is received thereafter. A relay method that performs flooding transfer in which the second communication frame is transmitted to each port other than the port that received the second communication frame. Performing the flooding transfer on a communication frame addressed to the source address received after transmission of the validity check request,
The unicast transfer is performed again for a communication frame addressed to the transmission source address received after that when a validity confirmation response indicating that communication with the transmission source address is possible is obtained. The relay method described. Receiving the validity check request transmitted in the relay method according to claim 6 or 7,
At least, when recognizing that communication addressed to the transmission source address is possible, a validity confirmation response indicating that communication addressed to the transmission source address is possible is sent to the transmission source of the validity confirmation request. Send Validity confirmation method. After receiving the first communication frame, when the second communication frame addressed to the transmission source address of the first communication frame is received, the second communication frame is changed to the port that has received the first communication frame. Relay control processing for performing unicast transfer to be transmitted to the receiving port,
After receiving the first communication frame, when a state in which a communication frame whose transmission source address is a transmission source has not been received exceeds a predetermined valid time, an inquiry is made as to whether communication with the transmission source address is possible. A first computer program that transmits a validity check request to the reception port and causes a computer to execute a validity inquiry process capable of receiving a validity check response that is a response to the validity check request. ,
In the relay control process,
In response to the validity confirmation request, if a validity confirmation response indicating that communication with the transmission source address is possible is not obtained, a second communication frame addressed to the transmission source address is received thereafter. A first computer program that performs flooding transfer in which the second communication frame is transmitted to each port other than the port that received the second communication frame. Receiving the validity check request according to claim 10;
When it is recognized that communication addressed to the transmission source address is possible, a validity confirmation response indicating that communication addressed to the transmission source address is possible is transmitted to the first communication device. A second computer program causing a computer to execute validity response processing.

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