JP2003244197A - Route redundant system and method for minimizing communication disconnection time during partial failure in router - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress a time for packet loss and communication disconnection at the minimum during failures in a router. <P>SOLUTION: A packet transfer unit and a routing protocol processing unit are made to be independent, and these units can be exchanged physically without stop in operation of other units and can continue their operation without being affected by failures in other units. In addition, the packet transfer unit has a dual construction of a working unit and a standby unit, and comprises an automatic detecting means for detecting failures in the working unit and an automatic switching function corresponding to detection. By arranging the routers of 2 sets or more at the border of the network side operated with ISP, etc., to secure a redundant route with a user network to be connected, and connecting for enabling automatic switchover of a route by routing protocol, a time for packet loss and communication disconnection is suppressed at the minimum during failures in a router. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to high reliability of an IP network, ensuring of connectivity, and availability. More specifically, the present invention relates to communication disconnection due to a failure of a router by a bypass route using a routing protocol. The present invention relates to a function for automatically recovering communication, and relates to a technique for minimizing the time of communication interruption / packet loss due to router failure.

[0002]

2. Description of the Related Art A routing protocol in IP is used for automatic distribution of route information in networks and detour control in redundant routes. Conventionally, as a system for avoiding a connection failure of a connected device in a network system, an example of a system in which a router is duplicated is disclosed in Japanese Patent Publication No. 11-261561.
As shown in FIG. 11, in this conventional system,
Routers 1 and 2 duplicated in a network system for connecting communication between terminals via one or more networks 10, 20, ... And each of these routers has an IP address 101; 201 and a MAC address 1
02; 202, Dip switch 103; 203, duplex control function 104; 204, and transmission processing unit 105; 2
05, a reception processing unit 106; 206, a routing processing unit 107; 207, and a control unit 10 for controlling each element.
9; 209, a recording medium 110; 210 in which a program for controlling the router duplication system is recorded, and ports 11, 12, ... 1n; 21, 2 for connecting to each network.
2 and 2n have exactly the same configuration, and both duplex control units 104 and 204 have health check request transmission processing functions 1041 and 2041, health check request reception processing functions 1042 and 2042, and port failure. It has the same configuration including the processing functions 1043 and 2043,
This conventional system improves network availability by switching between two routers having the same IP address and physical address.

[0003]

However, in the detour control by the routing protocol and the redundant route, the route disconnection between the routers and the failure of the router are detected, and the route is recalculated based on that. Until the route is changed, communication is cut off and packet loss occurs. In addition, since many general routing protocols such as OSPF and BGP have the state of routing protocol processing, if the state is not inherited at the time of switching, even if the router is switched with the same address, the route information starts from zero. Therefore, communication disconnection will inevitably occur until the routing protocol processing becomes stable.

In view of the above-mentioned problems, the present invention provides a method for controlling packet loss and packet loss in detour control by automatic route change using a routing protocol when a router fails.
The purpose is to minimize communication interruption time.

[0005]

According to the present invention, two or more sets are installed in a network that operates IP, etc., a redundant route is secured between the network and a user network connected to the network, and the route is automatically switched by a routing protocol. In a route redundancy system with routers connected to each other, each of the routers can be physically replaced without stopping the operation of the other, and operate without being affected by other failures. It comprises a continuous IP routing protocol processing unit and a duplicated packet forwarding unit,
The routing processing unit simultaneously changes the routing information of the duplicated packet transfer unit at the time of changing the routing, the function of synchronizing the routing information at the time of returning the duplicated packet transfer unit to the duplicated state, and the function of the failed routing processing unit. There is a function of updating the routing to the latest state at the time of restoration, and the packet transfer unit has an automatic failure detection function and an automatic switching function.

In a preferred embodiment of the present invention, the packet transfer unit and the IP routing protocol processing unit are independent devices, and each has an interface for connecting to each other.

In another preferred embodiment of the present invention, an independent packet transfer device handles a plurality of independent routing tables such as a plurality of VPNs, identifies an independent network, and distributes it to an appropriate routing protocol processing section. The independent and independent IP routing protocol processing device having a function performs a plurality of independent routing protocol processes, identifies an independent network, and performs a route calculation process by an appropriate independent routing protocol processing unit. , And has a function of setting the route calculation result in an appropriate routing table of an appropriate packet transfer device.

Further, according to the present invention, two or more sets are installed in a network operating IP and the like, a redundant route is secured between the network and a user network connected to the network, and a route can be automatically switched by a routing protocol. Routers connected to each other, each of which is physically replaceable without interruption of other operations,
Further, it comprises an IP routing protocol processing unit and a duplicated packet transfer unit capable of continuing the operation without being affected by other failures, and the routing processing unit simultaneously provides the routing information of the duplicated packet transfer unit at the time of changing the routing. The packet transfer unit has a function of changing, a function of synchronizing routing information when the failed packet transfer unit returns to duplication, and a function of updating the routing to the latest state when the failed routing processing unit is restored. , A router having an automatic failure detection function and an automatic switching function.

Further, according to the present invention, two or more sets are installed in a network that operates IP and the like, a redundant route is secured between the network and a user network connected to the network, and a route can be automatically switched by a routing protocol. In the method of minimizing the communication interruption time when a partial failure occurs in the router connected to, the IP routing protocol process and the packet transfer process in each of the routers are made independent, and the packet transfer process is duplicated, and the routing process is performed when the routing is changed. Changing the routing information by the duplicated transfer process at the same time,
There is a step of synchronizing the routing information when the failed packet transfer process is restored to duplication, and a step of updating the routing to the latest state when the failed routing process is restored, wherein the packet transfer process is an automatic failure detection step. And a automatic switching step, which is a method for minimizing the communication interruption time at the time of a partial failure of the router.

In a preferred embodiment of the present invention, the independent packet transfer process handles a plurality of independent routing tables such as a plurality of VPNs, identifies an independent network, and allocates the appropriate routing protocol processing unit. The independent and independent IP routing protocol processing process performs a plurality of independent routing protocol processes, identifies an independent network, performs a route calculation process by an appropriate independent routing protocol process, and Have a step to set the calculation result in the appropriate routing table.

As described above, according to the present invention, one router is divided into a packet transfer unit and a routing protocol processing unit having independence, and further, the packet transfer unit is duplicated, whereby the router is In addition to maintaining the packet transfer function in the event of a partial failure, secure redundant paths by arranging two or more routers to minimize communication interruption and packet loss during the time until the route is switched by the routing protocol. To

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Next, in order to describe the present invention in more detail, embodiments of the present invention will be described with reference to the accompanying drawings. In the drawings, the same components are designated by the same reference numerals.

[First Embodiment] FIG. 1 is a diagram showing a configuration and an arrangement of a first embodiment of a router according to the present invention applied to a network system in which an ISP network 1100 and a user network 1101 are integrated. Here 10
191 is a router according to the present invention at the boundary of the ISP network 1100, and 109;
It is a user router at the boundary of the user network 1101. The router 101; ... 191 according to the present invention includes a routing protocol processing unit 102; ... 192, and a working packet transfer unit 10 which constitutes a packet transfer unit having a duplex configuration.
3; ... 193 and standby system packet transfer unit 105;
5, and interfaces 1071, 1072, ... 107n; ..., 1971, 197 on the ISP network 1100 side.
2, ... 197n and interfaces 1081, 1082, ... 108m on the user network 1101 side;
81, 1982, ... 198m respectively.

, 191 according to the present invention, for example, the router 101 includes packet transfer units 103 and 105.
And the routing protocol processing unit 102 are independent,
Each of these units can be physically exchanged without stopping the operation of other units, and can continue to operate without being affected by other failures. Furthermore, the packet transfer unit can transfer the active packet as described above. The unit 103 and the standby system packet transfer unit 105 are duplicated so that the packet transfer units of both systems have an automatic failure detection function and an accompanying automatic switching function.

Such routers 101 and 191 are used as ISPs.
For example, two or more sets are installed on the boundary of the operating network side, a redundant route is secured between the user network 1101 to be connected, and the route is switched so that the route can be automatically switched by the routing protocol.

Normally, the connected user network 1
199 of the router 101 and the routing protocol processing unit 102 of the router 101 according to the present invention; 192 exchanges routing information according to the routing protocol, and the routing table as a result of the route calculation. Alternatively, the difference between the routing information is calculated by using the routing tables 104, 106 in the packet transfer units of both the active system and the standby system;
4,196 are set at the same time each time. The active system packet transfer units 103; ... 193 perform packet transfer based on the setting. At this time, the standby system packet transfer unit 105; ... 195 is not performing packet transfer, but when the packet transfer unit is switched due to a failure of the active system packet transfer unit, the packet transfer can be started immediately. Waiting at.

Two routers of the present invention having the above-mentioned configuration are provided.
By installing more than one group in the ISP network 1100,
A redundant route is set between the user network 1101 and the connected user network 1101. As for whether all routes are used, that is, whether packets are flowing in all routes, the user network 1101. Depending on the relationship with 1101, specifically, all routes are always used for load balancing, partial traffic flows to each according to priority and distance, or only the highest priority route is used. The state will be different depending on whether or not the packet is transmitted, but in the following, the operation will be described with reference to FIG.

FIG. 2 is a diagram for explaining switching to a standby system due to a failure of the active packet transfer unit 103 in the router at the boundary of the ISP network 1100, for example, the router 101. As shown in FIG. 2, when the active packet transfer unit 103 fails, the active packet transfer unit 103 and the standby packet transfer unit 1
Due to the automatic failure detection and automatic switching function in 05, the standby system packet transfer unit 105 is switched as the new active system packet transfer unit (FIG. 3), and packet transfer is continued. However, each packet transfer unit 103; ... 19
The cycle for failure detection in 3, 105; ... 195 needs to be set shorter than at least the failure detection time by the routing protocol. As a result, the routing protocol processing unit 102 continues to operate even during the switching of the packet transfer unit, and the packet transfer unit is restored before the failure detection by the routing protocol, so the router 10 on the user network 1101 side is restored.
Also in 9; ... 199, switching by the routing protocol is not performed.

In order to restore the packet transfer unit to duplex,
As shown in FIG. 4, the failed old working packet transfer unit 103 is physically replaced with the new standby system packet transfer unit 1031.

In the routing protocol processing unit 102, when the packet transfer unit 103 fails, or
When the packet transfer unit 103 is removed, the failure of this packet transfer unit is detected. However, when the routing protocol processing unit 102 is replaced with a new packet transfer unit 1031, the current routing table 104 is detected.
Is set in the new packet transfer unit 1031 to synchronize the routing information and restore the exchanged packet transfer unit 1031 as a new standby system. As a result, the router 101 is completely restored to the normal state.

As shown in FIG. 5, when the routing protocol processing unit 102 in the router 101 fails, the active system packet transfer unit 103 and the standby system packet transfer unit 105 continue to operate as they are, and the routing protocol processing unit Since the packet is transferred in the routing table 104 at the time when 102 fails,
No packet loss occurs.

After that, the failure of the router 101 is detected by the routing protocol in the user network 1101 including the routers 109, ... 199 on the user network side and the router network 1100 on the ISP side. As shown in FIG. 6, the routing is changed to another redundant route.

As shown in FIG. 7, by replacing the failed routing protocol processor 102, the router 109 on the user network side and the router 101 on the ISP side again.
Information is exchanged between the new routing protocol processing unit 1021 and the new routing protocol processing unit 1021, and a new routing table is generated. In the packet transfer unit, the old routing tables 104 and 106 are used for transfer. Information on these old routing tables is deleted, and new routing tables are set in both the active and standby packet transfer units 103 and 105, respectively.

Further, by the restoration of the routing protocol processing unit 1021 of the router 101, recalculation of the route over the entire user router network 1101 and the ISP side network 1100 is performed, and the route is changed as necessary to completely Restore to normal state.

[Second Embodiment] FIG. 8 is a diagram showing the configuration and arrangement of a router according to a second embodiment of the present invention applied to a network system. The router according to the present invention in this example is the routing protocol processing device 201;
1 and a packet transfer device 202; ... 292 positioned at the boundary of the ISP network 2100.
Like the first embodiment, the packet transfer processing device 202; ... 292 uses the active system packet transfer section 203; ... 293 having the routing table 204; ... 294 and the standby system packet transfer section 205 having the routing table 206; … Has 295. The packet transfer processing device 202; ... 292 further includes an interface 2072 on the side of the corresponding routing protocol processing device;
Interface 2071 connected to 2972; ... 297
1. Interfaces 2073, ... 207 on the ISP network 2100 side connected to other routers in the ISP
n; ... 2971, ... 297n, user network 21
User router side interfaces 2081, connected to user routers 209, ...
2082, ... 208n; ... 2981,2982, ... 29
It also has 8n each.

As shown in FIG. 8, the router according to the present invention in this example has a routing protocol processing device 201 and a packet transfer device 202, which are physically independent of each other, so that no other operation is stopped. It is physically replaceable.

In the packet transfer device 202, the packet transfer unit is duplicated as the active system packet transfer unit 203 and the standby system packet transfer unit 205. As in the first embodiment, the active system and the standby system have the active system. It has an automatic failure detection and automatic switching function.

A router having the routing protocol processing device 201 and the packet transfer device 202 as a set is called an ISP.
For example, two or more sets are installed on the boundary of the network 2100 side that operates such as to secure a redundant route with the user network 2101 to be connected, and connect so that the route can be automatically switched by the routing protocol. The operation of this example is similar to that of the first embodiment described above.

[Third Embodiment] FIG. 9 is a diagram showing the configuration and arrangement of a router according to a third embodiment of the present invention applied to a network system. The ISP network 3100 is
.. 392 and the routing protocol processing devices 301, ... 391 corresponding to the respective packet transfer devices, and the user networks 3101, 3102, ... 310j are connected to the user routers 3091, 3092, respectively. , ... 309j; 3
, 399j are connected. The router according to the present invention in this example has a plurality of routing protocol processing units 3011, 3012, ... 301.
j; ... 3911, 3912, ... 391j having a routing protocol processing device 301; ... 391, and ISP
Packet transfer device 3 at the boundary of network 3100
02; ...; 392. 391 is connected to the corresponding packet transfer device 302;
072; ... 3972 is also included. Packet transfer device 3
02; ...; 392 are a plurality of active routing tables 3041 and 304 corresponding to a plurality of routing protocol processing units in the routing protocol processing device.
2, ... 304j; ... 3941, 3942, ... 394j, the active packet transfer unit 303; ... 393, and a plurality of routing tables 3061, 3062, similarly.
306j; ...; 396j, 3962, ... 396j, and a standby system packet transfer unit 305; The packet transfer device 302; ...; 392 is further
3971 for connecting to the corresponding routing protocol processor side interface 3072; 3971 for connecting to the 3972; interface 3 for the ISP network 3100 side connecting to other routers in the ISP
0397, ... 307n; ... 3971, ... 397n, user routers 3091, 3092 ,.
j; 3991, 3992, ... 399j user network side interfaces 3081, 3082
... 308m; ...; 3981, 3982, ... 398m, respectively.

As shown in FIG. 9, in addition to the device division of the second embodiment, the router according to the present invention of this example has a VPN, etc.
Multiple independent networks 3101, 3102, ... 3
By connecting the 10j and performing independent transfer and routing, the device can be shared to enable economical operation by the ISP or the like. The packet transfer devices 302, ... In the routing protocol transfer device 301, ..., 391, for example, as will be described later with reference to FIG. 10, an arbitrary combination enables a free and efficient accommodation and a scalable structure.

In the packet transfer device 302 of FIG. 9, a plurality of routing tables 304 in which the packet transfer units 303 and 305 of both the active system and the standby system are independent respectively.
1,3042, ... 304j; 3061,3062, ... 3
No. 06j is held, packet transfer is carried out accordingly, and an independent network is identified and assigned to appropriate routing protocol processing units 3011, 3012, ... 301j.

In the protocol processing device 301, a plurality of routing protocol processing units 3011 and 301
2, ... 301j each perform a plurality of independent routing protocol processes, identify an independent network, and perform appropriate independent routing protocol processing units 3011, 3012 ,. An appropriate packet transfer device 302
Appropriate routing tables 3041, 3042, ...
304j; 3061, 3062, ... Set to 306j.

The routing protocol processing unit 3 here
Each of 011, 3012, ..., 301j may be software, in which case it can be flexibly accommodated by being able to logically create and delete. However, in that case, some of the routing protocol processing units 3011 and 3
Even if the failure of 012, ..., 301j cannot be dealt with by restarting as software, the routing protocol processing device unit (301) is replaced.

When each of the routing protocol processing units 3011 3012, ..., 301j is constituted by independent hardware, flexibility of accommodation is lost, but restoration can be performed by partial replacement as in the above. .

FIG. 10 shows a routing protocol processing device and a packet transfer device according to the third embodiment of the present invention.
ISP is a router system in which two devices are combined to form a set for each independent user network such as VPN.
User networks 4101; 41 to be installed by connecting two or more sets at the boundary on the side of the operating network 4100;
02; 4103; ... and an example of the configuration of a network system in which a redundant route is secured and the route is automatically switched by a routing protocol. The operation is similar to that of the first embodiment. .

In FIG. 10, 401, 411, 4
Reference numerals 21, 431 and 441 denote a plurality of routing protocol processing units 4011 and 401 in the router according to the present invention.
2; 4111, 4112; 4211, 4212; 431
1, 4312, 4313; 4411, 4412, 441.
A routing protocol processor having three, 40
Reference numerals 2, 412, 422, 432, 442 are packet transfer devices in the router according to the present invention on the ISP network 4100 side. The packet transfer device includes active packet transfer units 4031, 4032, 4033; 4131,
4132, 4133; 4231, 4232; 4331,
4332; 4431, 4432 and standby system packet transfer units 4051, 4052, 4053; 4151, 415
2, 4153; 4251, 4252; 4351, 435.
2; 4451 and 4452. 4091,4
191; 4092,4192; 4093,4193; 4
094, 4194; 4095, 4195; 4096, 4
196 are user networks 4101; 41, respectively.
02; 4103; 4104; 4105; 4106. ISP network 410
0 is a packet transfer device 402, 412, 422, 43
2 and 442, and routing protocol processing devices 401, 411, and 4 having a correspondence relationship with these packet devices.
21, 431 and 441 are connected, and user networks 4101; 4102; 4103; 4104;
4105; 4106 are user routers 4091 and 419.
1, user routers 4092 and 4192, user router 4
093 and 4193 are connected to each other.

[0037]

As described above, according to the present invention,
Even if a partial failure of the router occurs, the routing is not changed by the automatic switching of the packet transfer unit,
Even if the communication is continued as it is, or even if the routing is changed, by continuing the packet transfer until the change is completed, the communication interruption / packet loss can be minimized to the end user. It has a remarkable effect that it does not make the user feel that the communication is interrupted.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration and an arrangement of a router according to a first embodiment of the present invention in a network system.

FIG. 2 is a diagram for explaining switching to a backup system due to a failure of a working packet transfer unit.

FIG. 3 is a diagram showing a flow of transfer packets after switching to a backup system due to a failure of a working packet transfer unit.

FIG. 4 is a diagram showing a flow of transfer packets after restoration by replacement of a failed packet transfer unit.

FIG. 5 is a diagram showing a flow of transfer packets when a routing protocol processing unit fails.

FIG. 6 is a diagram showing a flow of a transfer packet when a route is changed due to a failure of a routing protocol processing unit.

FIG. 7 is a diagram showing a flow of transfer packets after recovery by replacement of a failed routing protocol processing unit.

FIG. 8 is a diagram showing a configuration and an arrangement of a router according to a second embodiment of the present invention in a network system.

FIG. 9 is a diagram showing a configuration and an arrangement of a router according to a third embodiment of the present invention.

FIG. 10 is a diagram showing an example of the configuration of a third embodiment according to the present invention.

FIG. 11 is a diagram showing a conventional technique.

Description of symbols 101, ... 191 Router 102, ... 192 Routing protocol processing unit 1021 New exchanged routing protocol processing unit 103, ... 193 Active packet transfer unit 1031 New exchanged packet transfer unit 104, ... 194 Active system routing table 105, ... 195 Standby system packet transfer unit 106, ... 196 Standby system routing tables 1071, 1072, ... 107n; ... 1971, 197
2, ... 197n ISP network side interfaces 1081, 1082, ... 108m;
2, ... 198m User network side interface 109, ... 199 User router 1100 ISP network 1101 User network 201, ... 291 Routing protocol processing device 202, ... 292 Packet processing device 203, ... 293 Active packet transfer unit 204, ... 294 Active system Routing table 205, ... 295 Standby system packet transfer unit 206, ... 296 Standby system routing table 2071, ... 2971 Interface 2072, ... 2972 Interface 2073, ... 207n; ... 2973, ... 297n IS
Interfaces 2081, 2082, ... 208m on P network side;
2, ... 298m User network side interface 209, ... 299 User router 2100 ISP network 2101 User network 301, ... 391 Routing protocol processing device 3011, 3012, ... 301j; ... 3911, 391
2, ... 391j Routing protocol processing unit 302, ... 392 Packet forwarding device 303, ... 393 Working system packet forwarding unit 3041, 3042, ... 304j; ... 3941, 394
2, ... 394j Active system routing table 305, ... 395 Standby system packet transfer units 3061, 3062, ... 306j; ... 3961, 396
2, ... 396j Standby system routing table 3071, ... 3971 interface 3072, ... 3972 interface 3073, ... 307n; ... 3973, ... 397n interface 3081, 3082, ... 308m; ... 3981, 398
2, ... 398m Interfaces 3091, 3092, ... 309j; ... 3991, 399
2, ... 399j User router 3100 IPS network 3101, 3102, ... 31j User network 401, 411, 421, 431, 441 Routing protocol processing device 4011, 4012, 4111, 4112, 4211,
4212, 4311, 4312, 4313, 4411,
4412 routing protocol processing units 402, 412, 422, 432, 442 packet transfer devices 4031, 4032, 4131, 4132, 4231,
4232, 4331, 4332, 4431, 4432
Working system packet transfer units 4051, 4052, 4151, 4152, 4251.
4252, 4351, 4352, 4451, 4452
Standby system packet transfer units 4091, 4191, 4092, 4192, 4093
1,4193,4094,4194,4096,419
6 User Network 4100 ISP Network 4101, 4102, 4103, 4104, 4105
4106j User network

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masayuki Inoue             2-3-1, Otemachi, Chiyoda-ku, Tokyo             Inside Telegraph and Telephone Corporation F term (reference) 5K030 HA08 HD03 KA05 LB08 MD02

Claims (9)

[Claims] 1. Two or more sets are installed in a network that operates IP, etc., and a redundant route is secured between the network and a user network connected to the network, and the routes are automatically switched by a routing protocol. In a route redundancy system by routers, each of the routers can be physically replaced without stopping the operation of the other routers, and an IP routing protocol processing unit capable of continuing the operation without being affected by other failures. And a duplicated packet transfer unit, wherein the routing processing unit simultaneously changes the routing information of the duplicated packet transfer unit at the time of changing the routing, and the synchronization of the routing information when the failed packet transfer unit returns to the duplicated state. Function and routing when the failed routing processing unit is restored A path redundancy system having a function of updating to the latest state, and the packet transfer unit having an automatic failure detection function and an automatic switching function. 2. The route redundancy system according to claim 1, wherein the packet transfer unit and the IP routing protocol processing unit are independent devices, and each has an interface for connecting to each other. 3. The independent packet transfer device has a function of handling a plurality of independent routing tables such as a plurality of VPNs, identifying an independent network, and allocating it to an appropriate routing protocol processing unit, and The independent IP routing protocol processing device performs a plurality of independent routing protocol processes, identifies an independent network, performs a route calculation process by an appropriate independent routing protocol processing unit, and displays the route calculation results. The route redundancy system according to claim 2, which has a function of setting an appropriate routing table of an appropriate packet transfer device. 4. Two or more sets are installed in a network operating IP or the like, and are connected so that a redundant route is secured between the network and a user network connected to the network, and the route can be automatically switched by a routing protocol. IP routing protocol processing unit capable of physically exchanging each router without stopping other operations and capable of continuing operation without being affected by other failures, and duplicated packet transfer And a function for the routing processing unit to simultaneously change the routing information of the duplicated packet transfer unit when the routing is changed, and a function for synchronizing the routing information when the duplicated packet transfer unit is restored to the duplicated state. A function that updates the routing to the latest state when the routing processing unit is restored A router, wherein the packet transfer unit has an automatic failure detection function and an automatic switching function. 5. The router according to claim 4, wherein the packet transfer unit and the IP routing protocol processing unit are independent devices, and each has an interface for connecting to each other. 6. The independent packet transfer device has a function of handling a plurality of independent routing tables such as a plurality of VPNs, identifying an independent network, and distributing the network to an appropriate routing protocol processing unit, The independent IP routing protocol processing device performs a plurality of independent routing protocol processes, identifies an independent network, performs a route calculation process by an appropriate independent routing protocol processing unit, and displays the route calculation results. 6. The router according to claim 5, which has a function of setting an appropriate routing table of an appropriate packet transfer device. 7. The router according to claim 6, wherein the routing protocol processing unit is software. 8. Two or more sets are installed in a network that operates IP, etc., and a redundant route is secured between the network and a user network connected to the network, and the routes are automatically switched by a routing protocol. In a method of minimizing communication interruption time when a router partially fails, the IP routing protocol process and the packet transfer process in each router are made independent, and the packet transfer process is duplicated, and the routing process is duplicated when the routing is changed. The method includes the steps of simultaneously changing the routing information by the forwarding processing, the step of synchronizing the routing information when the failed packet forwarding processing is restored to the duplex state, and the step of updating the routing to the latest state when the failed routing processing is restored. , The packet transfer A method for minimizing a communication interruption time when a partial failure occurs in a router, wherein the processing includes an automatic failure detection step and an automatic switching step. 9. The independent packet transfer process has a step of handling a plurality of independent routing tables such as a plurality of VPNs, identifying an independent network, and allocating to an appropriate routing protocol processing unit, and The independent IP routing protocol processing performs a plurality of independent routing protocol processing, identifies an independent network, performs a route calculation processing by an appropriate independent routing protocol processing, and appropriately calculates the route calculation result. 9. The method for minimizing the communication interruption time at the time of partial failure of the router according to claim 8, further comprising the step of setting in a different routing table.