JPH09153916A - Network connection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the reliability of the communication system by reducing the effect of a fault in a router on the communication system. SOLUTION: In the inter-LAN connection method interconnecting plural LANs via a wide area network to relay data among LANs located remote from each other, plural routers 1-10 are provided to a LANa and a representative protocol address on the LANa shared in common by the routers is defined for the LANa, and the routers are used logically as one router by designating the representative protocol in the case of relaying data and the data are relayed with routers 21-24 of other LANb-LANe via an ISDN 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an L network via a wide area network.
The present invention relates to an inter-network connection method for connecting between ANs (local area networks).

[0002]

Related Background Art Conventionally, in this type of connection method, as a typical form for connecting LANs at remote locations, there is a method of accessing one center (router) from a plurality of bases. Generally, in such a method, a circuit switching network such as an ISDN line is used, and a small number of WAN lines are used in a time-division manner from a large number of bases to efficiently use the WAN line. .

The router used in such a method includes
For example, slot type that uses multiple boards for line connection or 1
There was a stackable type that consisted of multiple routers connected to one main router.

[0004]

However, in the method of accessing one main router described above, when the main router fails, the LAN connection becomes impossible and the influence on the communication system is great. There was a problem that reliability was lost. The present invention has been made in view of the above problems, and an object of the present invention is to provide an inter-network connection method that reduces the influence of a failure of a router on a communication system and improves system reliability.

Another object of the present invention is to provide an inter-network connection method capable of operating the group router function of the router even when the group router in the same LAN is separated into different ports by the device having the bridge function. To provide.

[0006]

In order to achieve the above object, the present invention connects a plurality of LANs via a wide area network such as an ISDN line network in order to relay data between networks such as remote LANs. In the inter-network connection method, a plurality of LAN inter-connection devices are provided in the LAN, the plurality of LAN inter-connection devices are logically used as one relay means (group router), and another LAN is connected via the ISDN line network. A network connection method for performing data relay with a LAN connection device in the network is provided, and a plurality of LAs are provided.
The N-to-N connecting device is used on the center side to cope with a failure of each LAN-to-LAN connecting device.

In claims 2 and 3, each LA in the same LAN is
By defining a hardware address (representative protocol address) on the LAN shared by the N-to-N connection device and logically operating as one group router by designating the representative protocol address during data relay, The terminal can make a call request without being aware of a plurality of LAN-to-LAN connecting devices, and each LAN-to-LAN connecting device transmits / receives routing information by the shared representative protocol address and transmits the same routing information. To have.

[0008] In claims 4 and 5, each LA in the same LAN
Each of the N-to-N connecting devices has a priority set in advance to prepare for a call request, and also manages the line use state of each of the LAN connecting devices, and when the call request is made, the priority and the line are set. Depending on the usage status, for example, when the LAN connection device having a higher priority than the own device is in the line usage status, the own device connects to the ISDN line network and the data is relayed to the LAN connection device in another LAN. At the same time, the line use status of the own device is transmitted to the other inter-LAN connecting device on the same LAN to notify that the own device is using the line.

According to a sixth aspect of the present invention, at least one inter-LAN connecting device in the same LAN manages the line use state of each inter-LAN connecting device, and when a call request is made from the terminal,
Depending on the line usage status, for example, a certain LAN with high priority
If the inter-connection device is using the line, the relay data is transferred to the inter-LAN connection device of the next priority within the same LAN.

According to claims 7 and 8, a hardware address and a physical address (representative protocol address and representative hardware address) on the network shared by the inter-LAN connecting devices in the same LAN are defined, and one of them is defined. The inter-LAN connecting device responds to the address request of the physical address corresponding to the representative protocol address with the representative hardware address, and the source address of the response is the responding inter-network connecting device. By setting the uniquely defined physical address, the representative protocol address and the representative hardware address are designated at the time of data relay,
Even if they are separated by a bridge device having a bridge function, each LAN connecting device logically operates as one group router.

In claim 9, a LAN within the same LAN
The inter-network connection device has routing information for a destination communicable via the ISDN line network as route information via the group router, and one of the inter-network connection devices is the wide-area device. When connected to another network via the network, announces the route information via the own device so that the route information via the own device is more optimal than the route information, and when the connection is disconnected. Announces that the route information via the device itself is unreachable and announces as route information via the group router.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION An inter-network connection method according to the present invention will be described with reference to the drawings of FIGS. FIG.
FIG. 1 is a configuration diagram showing a first embodiment of a communication system using the inter-network connection method of the present invention. In the figure, L
The ANa includes a plurality of routers (hereinafter referred to as “group routers”) 1 to 10 that operate as group routers, end nodes (terminals) 11 and 12, and these routers 1 to 1.
0 and the transmission path 13 to which the terminals 11 and 12 are connected.

The group routers 1 to 10 are routers 21 to 21 of other LANb to LANe via the ISDN line network 20.
24 is connected so that data relay is possible. In each of the group routers 1 to 10, a protocol address and a MAC address are individually set, and a hardware address (representative protocol address) on the shared LAN is set, and the routers are grouped by this representative protocol address. , The terminal is logically configured to consider multiple routers as one router. In particular,
It is possible to connect a plurality of ISDN-compatible routers to one representative telephone group and perform communication by using an idle line. Also, IP is supported as a communication protocol. The routers 1 to 10 have priorities set in advance, and in this embodiment, the router value 1
Among 10 to 10, the router with the smaller value is the router with the higher priority.

Each of the group routers 1 to 10 has a group router list in addition to a routing table in which routing information such as a protocol address of a relay destination router corresponding to a destination protocol address is registered. FIG. 2 is a block diagram showing an example of the group router list. In the group router list, each router and the values 1 to 10 indicating its priority, the protocol address, the MAC address, and the router assigned to each router are connected via the ISDN line network 20 to the connection partners currently connected. The protocol address is stored.

In the entry of this list, "158.202.50.5" described in the current connection partner is described.
1 ”is the protocol address of the router 21, and“ 158.
“202.50.53” is the protocol address of the router 22, “158.202.50.55” is the protocol address of the router 23, and “158.202.50.10”.
“0” indicates the protocol address of the router 24. Also, the group routers 1 to 10 in this case
The representative protocol address of is set to "158.202.232.50" indicating all group routers.

The group router according to the present invention has the following three functions: a group router detection function, a representative protocol address routing function, and a representative ARP (address resolution protocol) function. 1. Group Router Detection Function The routers 1 to 10 operating as group routers periodically transmit a group router detection packet and store the connection status of other routers in the group router list.

Each of the routers 1 to 10 in the group transmits this group router detection packet by broadcast (representative protocol address or broadcast for network layer, broadcast or multicast for MAC layer). It is assumed that this packet and each packet described later use a UDP (User Datagram Protocol) packet of IP (Internet Protocol).

The format of the group router detection packet is, as shown in FIG. 3, the protocol address of the other party to which this packet is transmitted (representative protocol address commonly assigned to the group router) or the destination address indicating broadcast and the source. , An IP header part having a source address indicating the protocol address of its own device, a length indicating the packet length, and a packet type (for example, “1” in the case of a group router detection packet). ), A region indicating the priority of the device itself within the group, a region indicating the MAC address of the device itself,
An area showing the number of available free channels, a partner protocol address showing the protocol address of the connected partner router currently connected via the ISDN line (if there are a plurality of connected partners, a plurality of corresponding partner protocol addresses) It is composed of a data section having. Each entry sets the partner protocol address of all channels that are in a call waiting state, a calling state, or a connected state among the usable channels. All channels are ISD
It is set to be used as an N line.

When the group router receives this detection packet, the protocol address of the router in the packet,
The MAC address and the protocol address of the partner router connected via the ISDN line are registered in the group router list in the self-apparatus in order from the highest priority, for example. FIG. 2 shows an example of this group router list. Each entry of this group router list is subjected to aging after new registration, and if no group router detection packet is received from that router for a certain period of time, it is considered that the router did not exist and is deleted from the list.

When receiving the group router detection packet, the group router recognizes the connection partner of each router in the same group from the group router list of its own device, and the connection partner of the router having a higher priority than the self device. Disconnects the line with the other party, when is connected with the other party. When the device is activated, each router transmits a channel state request packet to another group router and collects the channel states of the other group routers.

The format of this channel status request packet is, as shown in FIG. 4, a destination address, a source address, and a packet type (in this case, for example, "2") similar to those of the group router detection packet.
In addition to the command, the priority of the device itself, and the MAC address of the device itself, it is composed of a reserve which is a reserve area. Each group router responds to the above channel state request packet by transmitting the group router detection packet shown in FIG. 2. Routing function based on representative protocol address In addition to the protocol address of the own device, a representative protocol address that is commonly assigned is set in the group router as described above. When each group router transmits a packet of routing information (IP: RIP (routing information protocol)) to a terminal on the LAN or a router of another LAN via the LAN or ISDN line, this representative protocol address is used as a source address. Send. The format of the packet for transmitting the routing information is an Ethernet header part having a destination composed of a MAC address and a source address, and an IP header part having a destination composed of a protocol address and a source address after that.
It is composed of a data section and the like.

The router that has received the packet of routing information can register the routing information in the packet in a routing table (not shown) for each representative protocol address. When the relay packet is received, the relay process is performed according to the procedure shown in the flowchart of FIG. However, in this embodiment, the smaller priority value of the preset group router is set as the higher priority router, and the MAC address of the router having the highest priority as the destination MAC address of the Ethernet header part and the MAC address of the own device. Packets for which is set are handled as relay packets.

In the relay process, the router sends a duplicate confirmation packet containing the protocol address of the calling party to the LAN in consideration of the collision of the incoming and outgoing calls, and the channel of another group router The status and the protocol address of the calling party are collected, and the duplication confirmation is performed by recognizing the connection status between the terminal making the call request and another group router.

The format of this duplication confirmation packet is
As shown in FIG. 6, a common address indicating the same destination address, source address, and packet type (for example, “3” in this case) as in the channel state request packet.
d, own device priority, own device MAC address, res
In addition to the error, it is composed of the partner protocol address of the calling party.

As shown in FIG. 7, the format of the duplication confirmation response packet responding to the duplication confirmation packet is a command indicating a destination address, a source address, and a packet type (in this case, for example, "4").
d, own device priority, own device MAC address, res
In addition to the address of the other party and the protocol of the other party, the area indicating the connection state with the other party. 3. Representative ARP Function The group router responds to the ARP request from the terminal corresponding to the representative protocol address when the MAC address of the device itself has the highest priority in the group router list.

When a group router having a higher priority than the operating group router is activated in the state where a plurality of group routers are already in operation (for example, when a new group router is additionally connected) In order to update the address of the highest-priority group router, the highest-priority group router (new group router) broadcasts an ARP response packet in which the address (MAC address) of its own device is set.

The ARP request packet from this terminal is transmitted by broadcasting, and its format is, as shown in FIG. 8, a header section having a destination consisting of a MAC address and a source address, and a command indicating the type of packet. , Blank area, partner protocol address of the router whose MAC address you want to know, ARP
It is composed of a data section having a MAC address and a protocol address of the requesting terminal. The format of the ARP response packet is MA as shown in FIG.
Destination consisting of C address and source address (A
(A structure opposite to that of the RP request packet), a command indicating the type of the packet, a MAC address and protocol address of the own device, and a data part having the MAC address and protocol address of the ARP requesting terminal. Has been done.

Next, the inter-network connection operation of the group router will be described based on the flowchart of FIG. In this embodiment, a relay packet is transmitted from the terminal with the representative protocol address. Therefore, in the group router, all the routers 1 to 10 always receive the relay packet and judge whether or not the own device should relay the packet. Therefore, the case of the group router 3 will be described here as a representative.

In FIG. 5, when the group router 3 receives the relay packet (step 101), the group router 3 determines whether or not the relay destination router retrieved from the routing information and its own device are currently connected (step 102). Here, when the relay destination router and the own device are connected, a relay process for transmitting the relay packet to the relay destination router via the ISDN line network 20 is performed (step 10).
3). If the relay destination router is not connected to its own device, whether the relay destination router and other routers in the group router are currently connected is determined by the group router list ( (See FIG. 2) (step 104).

If the relay destination router and another router are currently connected, the relay packet is discarded (step 105). For example, when the relay destination router is the router 21, it is determined that the router 21 and the group router 1 are currently connected, and when the relay destination router is the router 22 or 23, the router 22 or 23 and the group router 5 are It is determined that the relay packet is currently connected, and if the relay destination router is the router 24, it is determined that the router 24 and the group router 10 are currently connected, and the relay packet is discarded.

If the relay destination router and other routers are not currently connected, it is judged whether or not there is an empty channel in the group router having a higher priority than the own device (step 106). In this case, the router 3 transmits the channel state request packet shown in FIG. 4 to the LAN, receives the group router detection packet (see FIG. 3) responded from each group router, and detects the detection packet. Recognize the free channels of each group router from the available free channels in

If there is a free channel in the group router having a higher priority than the own device, the group router having the higher priority is entrusted with packet relay and the received relay packet is discarded (step 107). Also,
If there is no free channel in the group router having a higher priority than the own device, it is determined whether or not the own device has a free channel (step 108).

Here, when the own device has an empty channel, after the line connection, the relay process is performed and the relay packet is transmitted to the relay destination router (step 109). in this case,
The router 3 transits the state of its own device based on the event and the channel state shown in the state transition diagram of FIG. In addition,
In FIG. 10, "not connected (ST0)" means a state in which the line is not connected and is in a state other than the following states (waiting for call, waiting for call, connected). "Waiting for call (ST1)" means on the LAN. A duplicate confirmation packet is sent to the LAN and is waiting for a response. “Calling (ST2)” means that there is no response to the duplicate confirmation packet sent to the LAN and the actual call processing is being performed. The "connection (ST3)" means a state in which a line is connected and communication is possible.

In FIG. 10, when there is a call request from the terminal, the router 3 first selects a channel to call from among empty (unconnected) channels, and confirms duplication including the protocol address of the calling party. Packet (see Figure 6) to LAN
Send up and wait for T1 response for a period of time. Upon receiving this duplication confirmation packet, the other group routers try to connect or try to connect to the other party having the protocol address included in the received packet on a channel in a state other than "unconnected" of their own device. Check if there is a channel in state. Then, if the channel exists, the duplicate acknowledgment packet (see FIG. 7) is used to respond with the protocol address and the state of the channel. If the channel does not exist, the received relay packet is discarded.

The router 3 which has transmitted the duplication confirmation packet,
When a duplicate confirmation response packet is received within the predetermined time T1 after waiting for the T1 response, the connection state of the duplicated group routers (other than the router 3) in the duplicate confirmation response packet However, in the case of "calling" or "connecting", the count of T1 is stopped for a certain period of time, and the calling process is not performed in the unconnected state.
However, when the connection status of the duplicated group router is "waiting for call origination", the priority of the other group routers in the duplicate confirmation response packet is lower than the priority of its own device (router 3). Determine whether Here, when the router 3 prioritizes itself, the router 3 waits for a call and then
When the calling process is performed and the other group router is prioritized, the count of the predetermined time T1 is stopped and the calling process is not performed in the unconnected state.

If there is no duplicate confirmation response packet within this fixed time T1, actual call processing is performed, relay processing is performed after line connection, and the relay packet is transmitted to the relay destination router. When the router 3 transits from the connected state to the unconnected state, it transits to the unconnected state when the disconnection process of the line is completed and the line is completely available.

If there is no free channel in the own device in step 108, the received relay packet is discarded and the relay process of the relay packet is left to the group router having a lower priority than the own device (step 110). ), The network connection operation is terminated. Therefore, in this embodiment, a representative protocol address is set in a plurality of routers, these routers are logically grouped as one group router, and another LAN is connected via the ISDN network.
Since the data is relayed to the relay destination router, the communication system with expandability can be provided.

Further, in the present embodiment, since a plurality of routers are used on the center side, even if each router fails, it is possible to deal with the failure, and the influence of the failure of the router on the communication system is affected. You can reduce the reliability of the system. Further, in this embodiment, the terminal can make a call request using the representative protocol address without being aware of the individual routers in the group router.

By the way, in this embodiment, all the group routers receive the relay packet and judge whether or not to relay each group router, so that the load on each group router becomes high. Therefore, in the present invention, RI is added as an additional function of the group router in order to improve this.
It is also possible to have an announcement function of the optimum route by P.

That is, in this announce function, when the group router connects an ISDN line to a certain connection partner, the protocol address set in the own device is used as the source address (source address) instead of the representative protocol address. LAN routing information
Announce up. At this time, it is announced as more optimal routing information than the routing information announced by the representative protocol address. For example, when using RIP, which is a typical routing protocol, the metric value indicating the distance of the route is used to set the routing information set to a value that is one or more smaller than the metric value announced by the representative protocol address. It can be realized by making an announcement.

With this function, each terminal on the LAN acquires more optimal routing information than the routing information based on the representative protocol address that has already been acquired. After that, each terminal can directly send data to the address set uniquely to the group router connected to the ISDN line, not to the hardware address corresponding to the representative protocol address. The load can be reduced.

When the group router disconnects the ISDN line, it is necessary to announce that the routing information via the protocol address of the own device is unreachable. In addition to the above-described embodiment, for example, a specific one of the plurality of group routers can manage the channel call instruction and the channel state of all the group routers. It should be noted that in this embodiment, this specific group router is called a calling instruction router.

In this embodiment, as the method of determining the calling instruction router, two types are defined, a static determination method and a dynamic determination method. First, in the statically deciding method, whether or not to operate as a calling instruction router is decided by setting on each group router.
The group router thus set as the calling instruction router always operates as a calling instruction router. Therefore, the function of the group router does not operate when the call instructing router goes down the system for some reason. Therefore, the following method of dynamically determining the call instructing router is preferable.

In the dynamic determination method, the priority of each group router is set in advance by using the above-mentioned group router detection function, and the group router detection packet including the priority of its own device is transmitted and received between the group routers. . Each group router learns the priority included in the group router detection packet, and operates as a calling instruction router when the priority value of its own device is the smallest.

When this calling instruction router receives the group router detection packet, the protocol address and MAC address of the router in the detection packet and the connection partner of the ISDN line of the router are registered in the group router list. Each entry in this group router list undergoes aging after new registration, and if no group router detection packet is received from that router for a certain period of time,
Assuming the router no longer exists, remove it from the list above.

When receiving the group router detection packet, the calling instruction router recognizes the connection partner of each router from the group router list of its own device and connects to the same partner redundantly with other routers. If so, disconnect the duplicate router line. It should be noted that there are various methods for selecting a router to be disconnected in the case of duplication, and thus no particular method is specified. For example, a method of disconnecting the line of the router selected at random, or disconnecting the line of the router with the lower priority can be considered.

In the routing function of this embodiment, the calling instruction router sends routing information reachable via the group router to the LAN. Therefore, when a terminal on the LAN communicates with a network reachable via the group router, it logically always communicates via the call instructing router. Further, the group routers other than the call instruction router do not transmit routing information reachable via the group router to the LAN.

The inter-network connection operation of the calling instruction router when the relay packet is received is as shown in the flowchart of FIG. In FIG. 11, step 20
Steps 1 to 205 are the same as steps 101 to 105 in FIG. 5, and it is determined whether or not the relay destination router retrieved from the routing information is connected to the own device (calling instruction router) or another group router, Similar processing is performed based on the determination.

However, in the present embodiment, when the relay destination router and the other router are not currently connected in step 204, the calling instruction router judges whether or not the other router has a free channel (step 206). . If another router has a free channel, after sending a connection request packet instructing the connection with the relay destination router to the other router that has the free channel, the relay data is sent to the other router. Transfer and entrust packet relay (step 2)
07). If the other router does not have a free channel, the calling instruction router determines whether or not its own device has a free channel (step 208).

Here, when the own device has an empty channel, the relay process is performed after the line connection and the relay packet is transmitted to the relay destination router as in step 109 of FIG. 5 (step 209). If there is no free channel in the device itself, there is no free channel in all the group routers, so the received relay packet is discarded (step 210) and the inter-network connection operation is terminated.

Group routers other than the calling instruction router are
When the connection request packet is received from the calling instruction router, the relay destination router is connected to the line, and the data transferred from the calling instruction router is relayed. In addition, the group routers other than the calling instruction router, after receiving the connection request packet,
The relay process is also performed for the data whose destination MAC address is the relay data addressed to the call-instructing router and which can be reached via the connected line.

In this embodiment, the calling instruction router manages the channel states of all group routers. Further, in the present embodiment, a function of detecting duplicate connection with the same partner on a plurality of channels is provided by cooperation between the calling instruction router and a group router other than the calling instruction router. In the channel management in the present embodiment, each group router performs periodic broadcast transmission, and when the channel state changes from the unconnected state to the connected state due to the call origination or the call termination of the line, or the channel state. Broadcasts a group router detection packet when is changed from the connected state to the unconnected state. The calling instruction router manages the channel states of all the group routers by the group router detection packet.

In this embodiment, the calling instruction router is
The channel status of each group router is set to "Not connected", "Call requesting" and "Connected", and "Not connected" means that the line is not connected and is not in the following states (call requesting, connecting) The "calling request" means the state after sending the connection request packet to the group router until receiving the group router detection packet containing the information that the channel has changed to the connection state from the group router, "Connected" means a state in which lines are connected and communication is possible.

Therefore, in this embodiment, one calling instruction router is determined from among the group routers, and the calling instruction router receives the relay packet and determines the group router to relay. Therefore, each group router It is possible to reduce the load of data relay to the. By the way, in the above-mentioned communication system, when a router and a terminal are performing data communication within the same LANa, another router and a terminal cannot perform data communication. Therefore, for example, as shown in FIG. 12, a case is considered in which the group routers 1 to 10 and the terminals 11 and 12 in the same LANa are connected by a bridge device having a bridge function such as a switching hub 14. The switching hub 14 connects the group routers 1 to 10 and the terminals 11 and 12 to different ports 14a.
14l are separately connected to each other, and have a registration table (see FIG. 13) for registering the MAC addresses of these devices and the port numbers to which each device is connected. With this configuration, the switching hub 14 enables data communication with a router or terminal other than the router or terminal performing data communication. In this example, the same reference numerals are used for the same components as those of the communication system shown in FIG.

In this case, however, when the highest priority group router responds to the ARP, its hardware address is learned by the above switching hub, so that the data addressed to the representative hardware address is not the highest priority group router. Sometimes it is not sent to the group router and the group router function does not work. Therefore, as a second embodiment of the present invention, for example, in the communication system shown in FIG. 12, a physical address (representative hardware address) for the representative protocol address “158.202.232.50” common to group routers is set. To do. In addition,
The representative hardware address is an address different from the unique hardware address individually registered in each group router, for example, "00: 00: 00: 00: 00".
"0:01" is set.

The highest priority group router resolves the hardware address to the representative protocol address (AR
P) is performed by this individually set unique hardware address instead of the representative hardware address set above. As a result, even in a communication system that uses a bridge device such as the switching hub 14, each router can operate the function of the group router without the representative hardware address being learned by the switching hub 14.

The group router of this embodiment also has three functions: a group router detection function, a routing function and a representative ARP function. 1. Group router detection function This function is the same as that of the first embodiment, and therefore its explanation is omitted. 2. In the routing function group router, the representative protocol address and the representative hardware address commonly assigned in addition to the protocol address of the own device are set as described above. When transmitting a packet of routing information (IP: RIP), each group router transmits this representative protocol address as a source address (source address). The RI that sends the routing information
The format of the P packet is as shown in FIG.
An Ethernet MAC header part having a destination and a source address composed of a MAC address, an IP header part having a destination and a source address composed of a protocol address thereafter, a UDP header part, a command indicating a request or a response, and a protocol of the destination. It consists of an address and a data part consisting of the number of hops.

The router having received the routing information packet stores the routing information in the packet as shown in FIG.
As shown in FIG. 5, each representative protocol address and corresponding representative hardware address can be registered in the routing table. When the relay packet is received, the relay process is performed according to the procedure shown in the flowchart of FIG. However, in this embodiment, a packet in which the representative hardware address set in the group router and the MAC address (physical address) of its own device are set as the destination MAC address is treated as a relay packet.

Further, in the relay processing, the router sends a duplicate confirmation packet (see FIG. 6) containing the protocol address of the calling party to the LAN in consideration of the collision of the incoming and outgoing calls, and The channel status of the group router and the protocol address of the calling party are collected by the duplicate confirmation response packet (see FIG. 7), and the duplicated confirmation is made by recognizing the connection state between the terminal that made the call request and another group router. I do. 3. Representative ARP Function The group router responds to the ARP request by the ARP request packet (see FIG. 8) broadcast from the terminal corresponding to the representative protocol address when the MAC address of its own device has the highest priority in the group router list. . However, the representative hardware address is set as the hardware address in the ARP response packet (the MAC address of the own device in FIG. 9) and the representative protocol address is set as the protocol address of the own device, and the source address in the MAC header part is set. Is set to the unique MAC address set in the own device.

When a group router with a higher priority is activated while a plurality of group routers are already in operation, the group router with the highest priority has the ARP response packet with the representative hardware address set. To broadcast. Even when a new group router is added and the same router becomes the highest priority router as a result of the negotiation, the highest priority group router broadcasts the ARP reply packet.

Therefore, in this embodiment, a representative protocol address and a representative hardware address common to a plurality of routers are set, these routers are logically grouped as one group router, and the ARP request packet is grouped. Since one of the routers responds with a response packet in which the above representative hardware address and the MAC address unique to each group router is set as the source address, the group router has a bridge function like a switching hub. Even if they are separated by the bridge device, the representative hardware address is not learned by the bridge device, and each group router can operate the group router function.

By the way, in the second embodiment, while the representative hardware address is not learned, the data from the host is always transmitted to all the ports of the switching hub 14, thus achieving the purpose of introducing the switching hub. Can not do. Therefore, in the present embodiment, only when the group router is in a connection state with a particular partner, the route information via the own device is announced so that it is more optimal than the route information via the group router, Operate the function of the router. That is, in this embodiment, when the ISDN line is connected and communication with a specific subnet (or network) becomes possible,
Routing information in which the metric (hop count) of the reachable destination (protocol address of the destination router) illustrated in FIG. 14 via the connected ISDN line is made smaller than the metric announced by the representative protocol address is announced. Then, at this time, by using the address of the LAN interface of the own device (not the representative hardware address) as the source address of the RIP packet, the ISDN is reached to the destination reachable via the ISDN line being connected. Realize that the router connecting the lines becomes the optimum route.

That is, in this announcement function, IS
When the DN line is connected, the group router connecting the ISDN line sets the routing information in which the metric for the destination reachable via the ISDN line is set to a value one less than the metric announced by the representative protocol address. It is transmitted on the LAN (LANa in the embodiment) by the RIP packet (see FIG. 14). At this time, the transmission source address of the RIP packet is set to the MAC address peculiar to the LAN interface itself. The routing information is periodically transmitted while the ISDN line is connected.

The terminal receiving the RIP packet creates a routing table based on the information in this packet and transmits a relay packet to the group router (to the MAC address unique to the router) connected to the ISDN line. It becomes possible to do. The MAC address unique to the router to which the relay packet is transmitted is learned from the source address in the RIP packet.

When the ISDN line is disconnected, the routing information for the destination which was transmitted as reachable via the disconnected ISDN line is transmitted as unreachable. At this time, the source address of the RIP packet is
Set the MAC address unique to the LAN interface itself. Further, when the group router learns new routing information from the remote router (a router connected to the above group router via the ISDN line) when the ISDN line is connected, it is necessary to notify the routing information to other group routers. is there. For this reason, when the group router learns new routing information from the remote router, the group router transmits the routing information to each group router as a RIP packet. The RIP packet is transmitted a fixed number of times at intervals of 30 seconds, for example.

Therefore, in the present embodiment, only when the group router is connected to a particular partner, the route information via the own device is announced so as to be more optimal than the route information via the group router. Therefore, each terminal on the LAN can acquire more optimal routing information than the already acquired routing information based on the representative protocol address.

[0067]

As described above, in the present invention, in the inter-network connection method for connecting a plurality of networks via a wide area network in order to relay data between remote networks, a plurality of networks are connected to the networks. An inter-connection device is provided, the plurality of inter-network connection devices are logically used as one relay means, and data is relayed with the inter-network connection device in another network via the wide area network, so that a failure of a router is communicated. Improve system reliability by reducing the impact on the system.

According to the second and third aspects, a hardware address on the network shared by the inter-network connecting devices in the same network is defined, and the hardware address is designated at the time of data relaying, thereby logically To 1
In addition to operating as one relay means, each inter-network connection device transmits and receives route information by the shared hardware address, so that the terminal can make a call request without being aware of the plurality of LAN inter-connection devices. ,
Each inter-network connection device can have the same routing information.

In Claims 4 and 5, priority is set in advance for each of the inter-network connecting devices in the same network, and the line usage status of each of the inter-network connecting devices is managed to make a call request. Then, the connection to the wide area network is made according to the priority and the line usage state, data is relayed with the inter-network connecting device in the other network, and the line usage state of the own device is changed to another one on the same network. Since the data is transmitted to the inter-network connecting device, it is possible to provide a communication system with expandability.

According to a sixth aspect of the present invention, at least one inter-network connecting device in the same network manages a line use state of each inter-network connecting device, and when a call request is made, the line use state is changed according to the line use state. Since the relay data is transferred to the other inter-network connecting device in the same network, the load of data relay on each group router can be reduced.

In claims 7 and 8, the hardware address and the physical address on the network shared by the inter-network connecting devices in the same network are defined,
When each of the addresses is designated at the time of data relay, it logically operates as one relay means, and one of the inter-network connection devices is an address of the physical address corresponding to the hardware address on the network. The shared physical address is responded to the request, and the source address of the response is set to the physical address defined uniquely to the responding inter-network connection device. Even if is separated into different ports by a device having a bridge function, the group router function of the above router can operate.

According to a ninth aspect, the inter-network connecting device in the same network has route information for a destination communicable via the wide area network as the route information via the relay means, and the inter-network connecting device is provided. One of
The one inter-network connection device announces the route information as route information via its own device when connected to another network via the wide area network, and when the connection is disconnected, Since it announces the route information via its own device as unreachable and announces it as the route information via the relay means, each terminal on the network is more optimal than the routing information based on the representative protocol address already acquired. Can be obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a first embodiment of a communication system using an inter-network connection method of the present invention.

FIG. 2 is a configuration diagram showing an example of a group router list of the present invention.

FIG. 3 is a configuration diagram showing a format of a group router detection packet of the present invention.

FIG. 4 is a configuration diagram showing a format of a channel state request packet of the present invention.

5 is a flowchart for explaining an inter-network connection operation of the group router shown in FIG.

FIG. 6 is a configuration diagram showing a format of a duplicate confirmation packet of the present invention.

FIG. 7 is a configuration diagram showing a format of a duplicate confirmation response packet of the present invention.

FIG. 8 is a configuration diagram showing a format of an ARP request packet of the present invention.

FIG. 9 is a configuration diagram showing a format of an ARP response packet of the present invention.

10 is a state transition diagram showing state transitions of the group router shown in FIG.

FIG. 11 is a flow chart for explaining an inter-network connection operation of the calling instruction router of the present invention.

FIG. 12 is a configuration diagram showing a second embodiment of a communication system using the inter-network connecting method of the present invention.

13 is a configuration diagram showing an example of a registration table included in the switching hub shown in FIG.

FIG. 14 is a configuration diagram showing a format of a RIP packet of the present invention.

FIG. 15 is a configuration diagram showing an example of a routing table of the present invention.

[Explanation of symbols]

 1-10 group router 11, 12 terminal 13 transmission line 14 switching hub 14a-14l port 20 ISDN line network 21-24 router a-e LAN

Claims (9)

[Claims] 1. An inter-network connection method for connecting a plurality of networks via a wide area network for relaying data between remote networks, wherein the network is provided with a plurality of inter-network connection devices. An inter-network connection method, characterized in that the inter-connection device is logically used as one relay means to perform data relay with an inter-network connection device in another network via the wide area network. 2. A relay unit logically defined by defining a hardware address on the network shared by the inter-network connecting devices in the same network and designating the hardware address at the time of data relay. 2. The inter-network connection method according to claim 1, wherein the inter-network connection method operates as. 3. The inter-network connection method according to claim 2, wherein each of the inter-network connection devices transmits / receives route information by the shared hardware address. 4. Each of the inter-network connecting devices in the same network has a priority set in advance, and also manages a line usage state of each of the inter-network connecting devices, and a line connection request is made. The inter-network connection method according to claim 1, wherein the inter-network connection device is connected to a wide area network according to the priority and the line usage state, and data is relayed with an inter-network connection device in another network. 5. The inter-network connecting device according to claim 4, wherein each inter-network connecting device in the same network transmits the line usage status of the own device to another inter-network connecting device on the same network. How to connect. 6. At least one in the same network
The two inter-network connecting devices manage the line use status of each inter-network connecting device, and when a call request is made,
The inter-network connection method according to claim 1, wherein the relay data is transferred to another inter-network connection device in the same network according to the line usage state. 7. A hardware address and a physical address on a network shared by each inter-network connecting device in the same network are defined, and each address is designated at the time of data relay to logically make one logical address. The inter-network connection method according to claim 1, which operates as a relay unit. 8. An inter-network connecting device among the inter-network connecting devices in the same network,
In response to the address request of the physical address corresponding to the hardware address on the network, the shared physical address is responded, and the source address of the response is uniquely defined to the responding inter-network connection device. The network connection method according to claim 7, wherein the physical address is set. 9. An inter-network connection device in the same network has route information for a destination communicable via the wide area network as route information via the relay means, One inter-network connecting device announces the route information as route information via its own device when connected to another network through the wide area network, and when the connection is disconnected, 9. The inter-network connection method according to claim 8, wherein the route information via the own device is announced as unreachable, and the route information via the relay means is announced.