JP2001127801A - Router - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a router at low cost capable of continuing routing without redundantly arranging plural routers for each of subnets when the router fails. SOLUTION: This router is provided with a mode switch timing detecting means for detecting the switch timing of an operating mode on the basis of a specified event inside the router, a repeater mode switching means for switching a connection between ports from router operation to repeater operation, a repeater processing part for connecting respective ports inside the router and transmitting the frame received from a certain port to all the other ports, an other device mode switching detecting means for detecting switching of the other router to the repeater mode, and a routing substituting means for substituting a routing function concerning the frame addressed to the other router.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a router, and more particularly to improving the reliability of a router in a LAN.

[0002]

2. Description of the Related Art FIG. 29 is a conceptual diagram of a conventional router.
The router 10 includes a first LAN line unit 1, a routing processing unit 2, a second LAN line unit 3, and a route information control unit 4. A subnetwork (hereinafter, a subnet) is connected to both ends of the router 10. One end of the first LAN line unit 1 is connected to the subnet, and the other end is connected to one end of the routing processing unit 2. A second LAN line unit 3 and a route information control unit 4 are connected to the other end of the routing processing unit 2.

In the system configured as described above,
Transfer data from the subnet is received by the LAN line unit 1 and sent to the routing processing unit 2. The routing processing unit 2 refers to a routing table held by the route information control unit 4 to determine a routing destination, and sends it to the LAN line unit 3. The LAN line unit 3 is connected to a subnet and sends transfer data to the subnet. The above operation is performed in the second L
The same applies to a case where transfer data is input to the AN line unit 3 from a subnet. As the route information control unit 4, for example, RIP / OSPF or the like is used. RIP
/ OSPF is a protocol for dynamically exchanging routing information between routers to create a routing table.

Conventionally, to ensure high reliability of a router, there is a method in which a plurality of routers are arranged in a redundant configuration in each subnet, and when one of the routers fails, another router substitutes a routing function. Has been taken.

FIG. 30 is a diagram showing a configuration example of a conventional system. In the figure, Si is a subnet, and R is a router. In each subnet, a router is arranged in a redundant configuration, and has a redundant configuration. Specific subnet S
The router connecting S5 and S6 is connected by a WAN line. With such a configuration, for example, when one of the routers fails, the other router can continue the routing operation and prevent the line from being disconnected.
In this case, proxy can be performed only between routers configured redundantly in the same subnet. In a conventional router, constant power is constantly consumed regardless of the traffic in the device.

[0006]

In the case where a redundant configuration is not adopted, if a router fails, there is a problem that a subnet under the router cannot communicate with another subnet. In order to solve this problem, if a redundant configuration is adopted in which a plurality of routers are arranged in each subnet, usually, router ports are occupied even for subnets that do not perform routing processing, Since the number of ports supported by the router cannot be fully utilized, 2
It was necessary to prepare more than twice as many routers. Furthermore,
In order to redundantly connect the subnets with a plurality of routers, a plurality of WAN lines are prepared, and the cost for ensuring high reliability is very large.

[0007] Regarding power consumption, in recent years, routers performing routing functions by hardware have been increasing in order to increase the speed, and the power consumption of the routers has tended to increase. The power that is wasted when the power is reduced has become non-negligible.

The present invention has been made in view of such a problem, and it is possible to continue a routing operation when a router fails, without arranging a plurality of routers redundantly for each subnet. It aims to provide a possible, low-cost router.

[0009]

(1) FIG. 1 is a block diagram of the principle of the present invention, showing the configuration of a router. The same components as those in FIG. 29 are denoted by the same reference numerals. In the figure,
11 is a mode switching trigger detecting means for detecting a switching trigger of an operation mode based on a specific event in the router;
12 is a repeater mode switching means for receiving the output of the mode switching trigger detecting means 11 to switch the connection between the ports from the router operation to the repeater operation, and 13 is connected to the LAN line sections 1 and 3 to connect each port in the router. And a repeater processing unit 14 for transmitting a frame received from a certain port to all the other ports, and another device mode switching detecting means 15 connected to the routing processing unit 2 for detecting that another router has switched to the repeater mode. Is a routing substitute unit that receives the output of the other device mode switching detection unit 14 and substitutes a routing function for a frame addressed to another router.

Reference numeral 16 denotes a traffic monitoring means connected to the mode switching trigger detecting means 11 for automatically detecting a drop in traffic in the apparatus. Reference numeral 17 denotes a traffic monitoring means connected to the routing proxy means 15 and uses a network management protocol to control each traffic in the network. Port information acquisition means for acquiring information necessary for the routing proxy function from the router, frame monitoring means for other devices connected to the other device mode switching detection means for monitoring frames addressed to other devices during operation of the router,
Reference numeral 9 denotes a loop detecting unit connected to the repeater mode switching unit 12 for recognizing a loop configuration of the network.
In the case where an AN or a different-speed LAN interface is mounted, this is an intra-medium connection means for connecting ports of the same medium. This is obtained by adding components 11 to 20 to the conventional configuration shown in FIG.

In the figure, the solid line indicates the flow of operation at normal time, the dashed line with a short interval indicates the flow of data when a failure occurs, and the dashed line with a wide interval indicates the flow of control (the same applies hereinafter). When the mode switching opportunity detecting means 11 detects the switching opportunity, the repeater mode switching means 12 fixedly connects each port in the router and switches from the router operation to the repeater operation. Here, the router operation is an operation of discarding a frame to each port according to the destination IP address, and the repeater operation is a dripping operation in which a signal passes through the router through the router. The repeater processing unit 13 transmits a frame received from each port to all other ports.

When the other device mode switching detecting means 14 detects that another router has switched to the repeater mode, the routing substitute device 15 substitutes a routing process for a frame addressed to the device in the repeater mode. Therefore, it becomes possible for the neighboring router to take over the routing function of another router at a certain moment.

(2) The invention according to claim 2 is characterized by comprising a traffic monitoring means for automatically recognizing a decrease in traffic in the device. Traffic monitoring means 16
However, when detecting a decrease in traffic, the repeater mode switching means 12 switches its own device from the router mode to the repeater mode in the same manner as in claim 1. Therefore, it becomes possible to cause the adjacent router to perform the routing function on the occasion of the decrease in the traffic in the router.

(3) The invention according to claim 3 is characterized by comprising port information acquisition means for acquiring information necessary for the routing proxy function from each router in the network using a network management protocol. .

The port information obtaining means 17 automatically obtains information to be used by the routing proxy function from each router in the network by using a network management protocol, and supplies the information to the routing proxy module 15. Therefore, it is possible to automatically perform the routing proxy function.

(4) The invention according to claim 4 is characterized in that it comprises a frame monitoring means for another device for monitoring a frame for another device during operation of the router. The other device-directed frame monitoring means 18 monitors the frame flowing through the network, and also refers to the port information of the other router acquired in advance, so that the frame addressed to the other router in the subnet to which the own device is not directly connected. Is notified to the other device mode switching detecting means 14. The other device mode switching detecting means 14 recognizes that this has triggered another device to switch the mode. Therefore, high-speed and reliable mode switching can be performed.

(5) The invention according to claim 5 is characterized by comprising a loop detecting means for recognizing a loop configuration of a network. The loop detecting unit 19 detects a loop between its own ports in advance using a spanning tree protocol or the like. Here, the spanning tree protocol is an effective protocol when the bridge is configured in a tree shape, and when the bridge changes from a tree shape to a loop shape, data is relayed indefinitely through the loop (broadcast storm). ) Means a protocol for breaking the loop and exiting the loop. When the mode switch trigger detecting means 11 detects the switch trigger,
The repeater mode switching means 12 connects only one representative port to another port with respect to a port in a loop. Therefore, it is possible to avoid a loop during the repeater operation.

(6) In the invention according to claim 6, the router is W
When an AN or a different-speed LAN interface is mounted, an intra-media connection means for connecting each port of the same media is provided.

When the mode switching trigger detecting means 11 detects the switching trigger, the intra-media connecting means 20 identifies the media of each port in the router and notifies the repeater mode switching means 12 of the port to be connected for each media. I do. The repeater mode switching means 12 fixedly connects each port in the router for the same medium and switches from the router operation to the repeater operation. When the other device mode switching detecting unit detects that another router has switched to the repeater mode, the routing substitute unit 1
Reference numeral 5 substitutes a routing process for a frame addressed to a device in the repeater mode transmitted from a port of a different medium. Therefore, when switching the repeater mode,
Media conversion becomes unnecessary.

[0020]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 2 is a diagram showing a configuration example of a network system to which the present invention is applied. In the figure, R1 to R6 are routers (hereinafter, Rx), and S1 to S10 are subnets (hereinafter, Sx) configured by each router Rx. In the figure, the case where the router R1 substitutes for R1 when a failure occurs in the router R1 is illustrated. Router R1 is connected to subnets S1 and S2, and router R2
Are connected to subnets S3 and S4. R1 and R2
Is connected to the subnet S5, and the subnet S5 is connected to the router R3. The routers R3 and R4 are connected by a WAN line, and the router R4 is connected to the subnet S6.

The subnet S6 is connected to the routers R5 and R6. Router R5 is connected to subnets S7 and S8, and router R6 is connected to subnets S9 and S10.

(Embodiment 1) A TCP / IP network to which dynamic routing by RIP / OSPF or the like is applied will be taken as an example, and an example in which the present invention is applied when a router operation stops due to a failure will be described. RIP / OSPF
Is a protocol that dynamically exchanges routing information between routers and creates a routing table.
P is a transport layer communication protocol, and IP is an Internet layer protocol.

The router of the present invention has both a function of switching to a repeater operation when the router operation is stopped due to a failure or the like and a function of performing a routing operation when another router switches to the repeater operation. Each function is
Each works independently. That is, when a failure occurs, a repeater operation is performed, and when another router failure is detected, a routing substitute operation is performed. These routers are connected to a routing processing unit 2, a routing processing unit 15, which operates at a normal time and during a proxy operation.
(See FIG. 1; the same applies hereinafter) and a repeater processing unit 13 that operates when a failure occurs.

FIG. 3 is a diagram for explaining the operation of the faulty router according to the first embodiment, and shows only means necessary for the repeater operation when a fault occurs. 1 are denoted by the same reference numerals. FIG. 5 is an explanatory diagram of the operation of the surrogate router according to the first embodiment, and shows only the means necessary for the surrogate surrogate operation when a failure of another router is detected.

In FIG. 2, in a state where each router is operating normally, when nodes in S1 and S2 communicate with nodes in other subnets, R1 performs a routing operation. In this state, it is assumed that a failure occurs in the router R1 and the operation of the router stops. The failure of the router operation is detected by the mode switching trigger detecting means 11. As a specific example, the routing processing unit 2 or the route information control unit 4 detects a hardware failure or a software failure in a hardware manner.

The mode switching trigger detecting means 11 which has detected the failure notifies the repeater mode switching means 12 of the failure. Upon receiving the failure notification, the repeater mode switching means 12 switches the ports in the router, which were normally connected to the routing processing unit 2, to the repeater processing unit 13 by setting a hard register or the like, and switches to the repeater operation. As a result, frame transfer can be continued. In this case, the frame will pass through the router through.

[0027] Repeater processing unit 1 in this embodiment
3 is supposed to be a simple hardware connection in which a frame received from a connected port is relayed to all other ports as it is in the same manner as a normal repeater. It is also possible to connect the ports having different speeds by fetching the received frame into a buffer once and relaying the frame according to the speed of each port, and perform media conversion even for WAN lines of different media, This can be handled by broadcasting the received frame to all connected ports in accordance with the media of each port.

Further, the load on the network can be reduced by having the bridge function of the repeater processing unit 13 learning the MAC address and transmitting the frame only to the corresponding port for the learned MAC address. Is also possible.

In the conventional router, if a failure occurs in the operation of the router of R1, the nodes in S1 and S2 cannot communicate with nodes in other subnets beyond their own subnet. On the other hand, in the present invention, it is possible to continue the frame transfer by disconnecting the routing processing unit 2 or the like in which the failure has occurred and switching to the repeater operation. The flow of processing when switching from the router operation to the repeater operation described above is shown in the failure occurrence operation flowchart of FIG.

FIG. 4 is an operation flowchart of the faulty router according to the first embodiment. The mode switching trigger detecting means 11 detects a failure in the router operation (S
1). Next, by the repeater mode switching means 12,
Hardware switching from the router operation to the repeater operation is performed (S2). Next, the repeater processing unit 13 transfers the frame received from the LAN line unit to another LAN line unit (S
3).

There is one problem here. Actual communication cannot be continued only by switching from the router operation to the repeater operation as in the present invention. This is because different subnets coexist on the same physical segment, and a conventional router cannot perform a routing operation well.

That is, in this embodiment, when the router R1 operates as a repeater, the subnets S1, S2,
S5 will be on the same segment. Regarding the substitution of the routing function for solving this problem, FIG.
A case in which 2 acts on behalf will be described as an example.

In the configuration of FIG. 2, there are two adjacent routers R2 and R3 on S5 when viewed from R1, but in the present invention,
One of the routers adjacent to the failed router performs routing. To determine which router will act for you,
RIP / OSPF can also be set in advance.
It is also possible to automate by comparing the size of the IP address of the adjacent router that can be obtained from the periodic exchange of the route information by.

FIG. 6 is an explanatory diagram of the internal configuration of the router R2 before performing the routing of the first embodiment. The subnet S5 is connected to the physical port 21 and is connected to the routing processing unit 2 via the logical interface 22.
The subnet S3 is connected to the physical port 24 and is connected to the routing processing unit 2 via the logical interface 23. Subnet S4 is connected to physical port 26,
It is connected to the routing processing unit 2 via the logical interface 25. The routing processing unit 2 is connected to the routing substitute means 15. In this state, the routing processing unit 2 is still performing the routing operation.

FIG. 7 shows the state of the address table of the interface (IF) of R2 when each router is operating normally in the configuration of FIG. When each router is operating normally,
The address table of R2 has only information on the subnets S3, S4, and S5 to which the own device is directly connected. The table shown in FIG. 7 includes the IF name and the corresponding I
It consists of a P address and a MAC address. For example,
The IP address for the S3 logical IF is the logical IF-IP of R2 S3, and the MAC address is the S3 logical IF-M of R2.
AC. S4 logical IF and S5 logical IF
The same applies to.

In addition, R2 when each router is operating normally
FIG. 8 shows the state of the routing table. The routing table of R2 includes a destination, a transmission logical IF, and a transmission physical I
F and a gateway. S1 to S1
In each of the entries up to 0, except for the directly connected subnets S3, S4, and S5, R
The IP addresses of the S5 logical IF of R1 and R3 are set.

FIG. 9 shows the state of the routing table of R3 at this time. Similarly, except for the directly connected subnet S5, S5 of R1 and R2 is used as a gateway.
The IP address of the logical IF or the IP address of the S6 logical IF of R4 is set. W from S6 to S10
They are connected by AN-IF. Conventional routers also operate in this state. That is, as shown in FIG. 6, while each router is operating normally, all the subnets, physical ports, and logical IFs are 1
There is a one-to-one relationship.

FIG. 10 shows a communication sequence when a node on S1 (hereinafter N1) communicates with a node on S3 (hereinafter N3) during normal operation. First, an ARP request is transmitted from N1 to R1 (S1), and the MAC address of the S1 logical IF of R1 is resolved by the ARP response from R1 (S2). The solution is to obtain a MAC address corresponding to the IP address. Thereafter, an IP frame addressed to N3 is transmitted to R1 (S3).

R1 searches the routing table and finds N
The gateway extracts the IP address of the S5 logical IF of R2 as a gateway for the frame addressed to 3 (S4). R1 to R2
ARP request is sent to (S5), and A
The MAC address of the S5 logical IF of R2 is resolved by the RP response (S6). Next, from R1 to R2, N3
The frame addressed to is relayed (S7).

Thereafter, N3 extracts the IP address of N3 because it is a subnet of the direct connection of R2 (S8). Next, an ARP request is transmitted from R2 to N3 (S
9) According to the ARP response from N3, N3's MA
The C address is resolved (S10). And finally, R2
The IP frame addressed to N3 is relayed from N1 to N3 (S1
1). As described above, the frame addressed to N3 becomes N1 →
It passes through two routers, R1 and R2, such as R1 → R2 → N3.

Next, the operation from when R1 switches to the repeater operation due to a failure until R2 takes over the routing of R1 will be described. FIG. 5 shows R2 acting for routing.
It is operation | movement explanatory drawing of. If R1 is switched to the repeater operation due to a failure, the other device mode switching detecting means 14
Detects that R1 has switched to the repeater operation. As a detection method, a periodic health check using Ping or the like from R2 can be considered. here,
Ping checks whether a response is returned by throwing a packet to the other party.

When the switching is detected, the other-device mode switching detecting means 14 notifies the routing proxy means 15 to determine whether or not the switching device itself is to be substituted. In this case, it is determined that the user himself / herself is acting on the basis of the above-described pre-setting or comparison of the IP address of the adjacent router.

FIG. 11 is an explanatory diagram of the internal configuration of the proxy router. 6 are denoted by the same reference numerals. In the figure, 30 is the S1 proxy IF, 31 is the S5 proxy IF,
Reference numeral 32 denotes an S2 proxy IF, which is provided between the physical port 21 and the routing processing unit 2, respectively. S1 agency IF
30 is the IP address / MAC address of S1 of the router R1, S5 proxy IF 31 is the IP address / MAC address of S5 of the router R1, and S2 proxy IF 32 is the IP address / MAC address of S2 of the router R1. To send and receive frames.

The routing substituting means 15 which has determined that the substituting is performed by the subroutine S1 to which the subroutine R1 is directly connected.
The proxy IF of 1, S2, and S5 is generated. FIG. 12 shows the state of the address table of the generated proxy IF. At this time, the IP address / MAC address used is the IP address / MAC of each logical IF of S1, S2, and S5 of R1.
Address. As a method of acquiring the address of R1, it is conceivable that R2 is set in advance.

As for the proxy IFs of S1, S2, and S5, a proxy flag is set to determine whether or not the proxy is an address table for proxy. The routing acting means 15
Further, it requests the path information control unit 4 to generate a proxy routing table addressed to S1 and S2. FIG. 13 shows the state of the proxy routing table generated. The difference from the table during normal operation shown in FIG. 8 is that the transmission logical IF of the entry addressed to S1 / S2 is different from the S1 proxy IF / S2 proxy IF.
And that the gateway is not the IP address of the logical IF of R1 and there is no gateway (R2
1, images directly connected to S2). Further, a proxy flag is set up and held, and whether or not the proxy table is a routing table for proxy is identified.

As described above, R2 becomes a proxy router of R1. Next, the flow of route information control in R2 acting as a substitute router will be described. An entry addressed to S1 / S2 in the routing table of R2 is notified to the adjacent router R3 on S5 using a routing protocol such as RIP or OSPF via an S5 proxy IF31 for proxying the S5 logical IF of R1. Are notified to R4, R5 and R6. The entry for S3 / S4 is S5 logical IF2
The notification is sent to the adjacent router R3 on S5 via R2, and further notified from R3 to R4, R5 and R6.

Conversely, entries other than those addressed to S1 / S2 are:
It is notified to the S1 / S2 area via the S1 proxy IF 30 and the S2 proxy IF 32 that substitute for the S1 logical IF / S2 logical IF of R1. Entries addressed to S6 to S10 are R3 to S
5 Received via the logical IF 22.

As described above, the connection routers on S1, S2, and S5 appear as if R1 exists. FIG. 14 shows a routing state in R3 generated by the route information exchanged with R2 or the like acting as a substitute router. The difference from FIG. 9 is that S
The gateway of the entry addressed to 1 / S2 is R1-S5
Logical IF-IP address or R2-S5 proxy IF-IP
Only the address part. However, R2-S
The 5-proxy IF-IP address is R1-S5 logical IF-I
Since the P address is used, the routing table of R3 is in exactly the same state before and after R2 substitutes for R1. That is, when R2 acts on behalf, R3 may operate as a conventional router.

FIG. 15 is a flow chart of the operation of the proxy router shown in FIG. 15 from the time when R1 switches to the repeater operation due to the failure until the time when R2 becomes the proxy router for R1. First, the other device mode switching detection means 14 detects a failure (switch to repeater processing) of another router (S1). Next, the routing proxy unit 15 determines whether or not it should become a proxy router (S2). Then, it is checked whether or not it should be substituted (S3).

If the proxy should be performed, the routing proxy unit 15 requests the route information control unit 4 to control the route information that requires the proxy after the generation of the proxy IF (S).
4). Next, the routing processing unit 2 substitutes for routing according to the table created by the routing proxy unit 15 and the route information control unit 4 (S5).

FIG. 16 shows a communication sequence when a node on S1 (hereinafter, N1) communicates with a node on S3 (hereinafter, N3) while R2 acts on behalf of R1. Where router R
Numeral 1 has only a repeater operation function, and has only a function of passing a signal through. First, from N1 to R2
The ARP request is transmitted to the (S1 proxy IF 30 shown in FIG. 11) (S1), and the MAC address of the S1 proxy IF 30 of R2 (the MAC address of the S1 logical IF of R1) is resolved by the ARP response from R2 (S2).

Then, N3 is added to R2 (S1 proxy IF30).
The destination IP frame is transmitted (S3). N3 is R2
, The IP address of N3 is extracted (S4). Next, an ARP request is transmitted from R2 to N3 via the S3 logical IF 23 (S5).
The MAC address of N3 is resolved by the ARP response from S3 (S6). And finally, from R2 to N3
Then, the IP frame addressed to N3 is relayed (S7).

As described above, even if R1 switches to the repeater operation, N1 can communicate with N3 without changing the settings of the default gateway and the like. The frame addressed to N3 passes through one router of R2 such as N1 → R1 (repeater operation) → R2 (proxy router) → N3.

According to the above method, the router can switch to the repeater operation when a failure occurs. Further, when a certain router switches to the repeater operation, the neighboring router can perform the routing.

(Embodiment 2) FIG. 17 is an explanatory diagram of the operation of R1 performing a repeater operation in Embodiment 2 of the present invention.
8 is an operation flowchart of R1 in the second embodiment. 17, the same components as those in FIG. 1 are denoted by the same reference numerals. In FIG. 17, reference numeral 16 denotes a traffic monitoring unit connected to the mode switching trigger detecting unit 11 and automatically recognizing a decrease in traffic in the apparatus. Other configurations are the same as those shown in FIG. Here, a case is considered in which a drop in traffic in the device is detected at R1 and a repeater operation is performed.

The traffic reduction in the device is detected by the traffic monitoring means 16. The traffic monitoring is performed as follows. The information for determining the traffic drop utilizes the MIB (RFC1213: MIB-II) in the device. Here, the MIB is various management information standardized for network management.

The total number of received octets (IfInOctet)
s) → Information for each interface Total number of transmission octets (IfOutOctets) → Information for each interface From the above information, the traffic (utilization rate) from a certain time X to a time Y in the device is calculated.

Total number of bytes transmitted / received between times XY = (If of Y)
IfInOctets of InOctets-X) + (Y
IfOutOctets of X-IfOutOctets of X
s) Total number of transmitted / received bytes per second = Total number of transmitted / received bytes between times XY /
(Y−X) Utilization rate = (total number of transmitted / received bytes per second × 8) / Ifspee
d (interface speed) The utilization rate is calculated for each interface, and the average utilization rate of all interfaces is calculated. The average utilization rate (bps) is compared with a preset traffic threshold value. If the average utilization rate is smaller than the traffic threshold value, it is determined that the traffic has dropped, and the mode switching opportunity detecting means 11 is notified of the traffic. The mode switching means 12 switches to the repeater operation. In addition,
The operation after the mode switching trigger detecting means 11 is the same as in the first embodiment.

Further, the substitution of the routing after R1 is switched to the repeater operation is performed by R2 as described above. The operation is the same as that described in the first embodiment. In this case, in order to prevent all the routers from performing the repeater operation, a setting in which the operation is not switched (a substitute router) is prepared. In this case, it is set to R2.

Further, the following settings can be made as parameters for calculating the average utilization rate. Utilization rate calculation interval (time between X and Y) Traffic threshold (bps) Permissible switching time (A: B to C: D) Monitored interfaces (a plurality of interfaces can be specified) Also, information for determining traffic drop As statistics (statistics per segment) of RMON1-MIB (RFC1775) supported in the device or RMO
ProtocolD of N2-MIB (RFC2021)
It is also possible to use ist (per protocol) / nlHost (per host) statistics.

Next, FIG. 18 will be described. The traffic monitoring means 16 periodically monitors the traffic in the device (S1). Next, it is checked whether or not the average usage rate <the traffic threshold value (S2). If not, the process returns to step S1. If so, the traffic monitoring means 16 notifies the mode switching opportunity detecting means 11 of the traffic drop (S3). The mode switching opportunity detecting means 11 notifies the repeater mode switching means 12 and switches the operation mode from the previous routing mode to the repeater mode (S4).

According to this embodiment, it becomes possible to cause an adjacent router to perform the routing function on the occasion of a decrease in traffic in the router. (Third Embodiment) FIG. 19 is an explanatory diagram of the operation of the proxy router R2 in the third embodiment, and FIG. 20 is a flowchart of the operation of the proxy router R2 in the third embodiment. 19, the same components as those in FIG. 1 are denoted by the same reference numerals. In the figure, reference numeral 17 denotes port information acquisition means for acquiring information necessary for a routing proxy function from each router in the network using a network management protocol, and is connected to the routing proxy module 15. Other configurations are
It is the same as FIG.

In FIG. 2, when the network management (SNMP) agent function of each router is operating, R1 switches to the repeater operation, and R1's IP address / MAC address required when R2 becomes the proxy router Considering a case in which proxy information can be automatically set without setting by acquiring port information such as the SNMP protocol.

The port information of R1 necessary for the proxy is obtained by the port information obtaining means 17. The following port information is required for each of the interfaces as the port information required for the proxy operation.

The IP address IP subnet mask IP broadcast address MAC address
Collects periodically using SNMP protocol. SN
As the IP address for MP communication, the source IP address of the routing control information exchanged by RIP / OSPF or the like (in this case, the IP address of the S5 logical IF of R1) is used. The collection is performed periodically in order to cope with a case where a setting such as an IP address is changed after the collection.

Specifically, the following MIB (RFC1) is set for each interface in which the IP address of the router R1 is set.
213: MIB-II) is collected. The collected information is as follows.

IpAdEntAddr (IP address) IpAdEntNetMask (IP subnet mask) IpAdEntBcastAddr (IP broadcast address) IfPhysAddress (MAC address) The port information acquisition means 17 holds the collected information,
1 switches to the repeater operation and prepares for itself as a proxy router.

Next, the flowchart of FIG. 20 will be described. The port information acquisition unit 17 periodically collects port information of the adjacent router (S1). In parallel,
The mode switching of the adjacent router is monitored (S2), and when the adjacent router is switched to the repeater mode, a proxy operation is performed using the collected port information (S3). This makes it possible to automatically solve the information required for proxy without setting and perform proxy, as compared with the method in which the port information of R1 is set in advance as described in the first embodiment.

(Fourth Embodiment) FIG. 21 is an explanatory diagram of the operation of the proxy router R2 in the fourth embodiment, and FIG. 22 is a flowchart of the operation of the proxy router R2 in the fourth embodiment.
In FIG. 21, reference numeral 17 denotes a frame monitoring unit for another device that monitors a frame addressed to another device during operation of the router, and is connected to the other device mode switching detection unit 14. Other configurations are the same as those in FIG.

In FIG. 2, consider the case where high-speed and reliable mode switching can be performed by monitoring a frame addressed to another device when R1 switches to a repeater operation and R2 acts as a substitute router.

The frame monitoring unit 18 for another device monitors the frame for another device, and detects that R1 has switched to the repeater operation. While R1 is operating as a router, S1 in FIG.
1 and R1 on S2 (M of S1 / S2 logical IF of R1)
The following frame addressed to the AC address is R2 (S
5) does not flow.

An ARP request frame for the IP address of R1 transmitted by the node on S1 / S2 to obtain the MAC address of R1 (the destination MAC address is a broadcast address). The node on S1 / S2 is a node on another subnet. IP frame to be transmitted to (destination IP address is a node on another subnet, destination MAC address is R1) After R1 is switched to the repeater operation, the frame flows from R1 to S5 and is received by R2. Become. The frame also reaches R3, but is discarded if it is not a substitute router.

In the case of the conventional router, when the above-mentioned frame (frame originally addressed to R1) is received, the frame is discarded. In R2, the frame monitoring means 18 for other device monitors the reception of the frame, and For frames,
It is determined that R1 has been switched to the repeater operation, and the other device mode switching detecting means 14 is notified. This is used as a trigger to instruct the routing proxy means 15, and R2 becomes a proxy router. The operation from the detection of the switching of the other device mode to the proxy router is the same as that of the first embodiment.

Next, FIG. 22 will be described. The other device-addressed frame monitoring means 18 monitors a frame addressed to an adjacent router (S1). Next, frame reception is monitored (S2), and when a frame is received, the other-device-addressed frame monitoring means 18 notifies the other-device mode switching means 14 (S3). Next, the other device mode switching means 14 notifies the routing substitute means 15 to start the substitute operation (S4).

According to this embodiment, as compared with the method of performing a periodic health check by ping or the like shown in the first embodiment, when the above-mentioned frame is received, the operation is switched to the immediate proxy router. Communication can be continued without stopping. Therefore, high-speed and reliable mode switching can be performed.

(Fifth Embodiment) FIG. 23 is a diagram showing a network configuration of a fifth embodiment, FIG. 24 is an explanatory diagram of an operation of R1 which performs a repeater operation in the fifth embodiment, and FIG. 25 is a fifth embodiment. FIG. 5 is an explanatory diagram of the operation of R1 in FIG.

In FIG. 23, R forming a loop
Consider a case in which R1 switches to repeater operation while R2 is in repeater operation at 1, R2. In FIG. 23, R1
When R2 and R2 are switched to the repeater operation, there is a problem that the connection path of S2 and S5 becomes a loop, and the data transfer is infinitely repeated, or a broadcast storm in which the system stops occurs. This is avoided by the loop detecting means 19 in FIG.

In the loop detecting means 19 of all routers,
Before switching to the repeater operation (during router operation), STP (Spanning Tree Protocol) is operated as if it were virtually operating as a bridge, and a loop at the bridge level is grasped in advance.

If a loop is detected at the bridge level, the interface having the lowest priority is held in the blocking state (the transmission and reception of frames are cut) by the STP. In FIG. 23, since R2 is in the repeater operation, either the S2 logical IF of R1 or the S5 logical IF enters the blocking state. In this case, the S2 logical IF is in the blocking state.

In this state, when R1 switches to the repeater operation, the repeater mode switching means 12 of R1 checks the STP information held by the loop detection means 19 and recognizes that the S2 logical IF is not connected. The repeater mode switching means 12 connects a port other than the S2 logical IF to the repeater processing unit.

Next, the flowchart of FIG. 25 will be described. First, when the loop detecting means 19 detects a loop (S1), the loop detecting means 19 sets a necessary port to a blocking state to avoid the loop (S2). next,
When the mode switching trigger detecting means 11 detects the mode switching trigger (S3), the mode switching trigger detecting means 11 notifies the repeater mode switching means 12 (S4). The repeater mode switching unit 12 refers to the state of the loop detection unit 19 and connects a port other than the blocking state to the repeater processing unit 13.

According to this embodiment, even if the system switches to the repeater operation, it is possible to avoid the occurrence of the broadcast storm. (Embodiment 6) FIG. 26 is a diagram showing a network configuration according to Embodiment 6, FIG. 27 is an explanatory diagram of an operation of R3 for connecting ports of the same medium in Embodiment 6 and FIG. 28 is an embodiment. 15 is an operation flowchart of R3 in Example 6.

In FIG. 27, reference numeral 20 denotes a case where the router has a WAN or a different speed LAN interface.
Intra-media connection means for connecting ports of the same media. 31 is a WAN connected to the opposite router
This is a line unit, and is connected to the routing processing unit 2.
A WAN line unit 32 is connected to the opposite router, and is connected to the routing processing unit 2.

Referring to FIG. 26, consider the case where R2 takes the place of R3 when R3 fails. R3 is R
4 is connected by a WAN line such as ATM or ISDN, and a redundant configuration is established by connecting R3 and R2 by a WAN line of the same medium. R3 is connected to S5 and S11 by a LAN line of the same media such as 100BASE-TX.

When R3 becomes an obstacle, Embodiment 1
In, all LAN ports and WAN ports are connected to the repeater processing unit 13, and frames received from any ports are transferred to all other LAN ports and WAN ports. At this time, since the media of the port is different, the received frame is temporarily stored in a buffer, and the media is converted according to the media of the transmission port and transmitted.

In the configuration of this embodiment, when the mode switching trigger detecting means 11 of R3 detects a failure in the router operation, the intra-media connecting means 20 identifies the medium of each port and connects the port for each medium. To the repeater mode switching means 12 to perform connection between the ports,
Connects between the LAN line 1 and the LAN line 2 and between the WAN line 1 and the WAN line 2 (see FIG. 26), which are the same media, and switches to the repeater mode.

The repeater 13 transmits a frame received from the LAN line 1 to the LAN line 2 and transmits a frame received from the LAN line 2 to the LAN line 1. Similarly, the frame transfer is performed for the WAN line. The proxy router R2 substitutes the routing process of R3 in the same manner as in the first embodiment.

For example, the frames from S1 to S6 are transferred along the path S1-R1-S5-R2-R3-R4-S6. The frames from S1 to S11 are transferred along the path S1-R1-S5-R2-S5-R3-S11.

Next, FIG. 28 will be described. First, the mode switching opportunity detecting means 11 detects a failure of the router operation (S1). Next, in-media connection means 2
0 notifies the repeater mode switching means 12 of the port to be connected for each medium (S2). Next, between repeater mode switching means 12, between LAN line sections, WA
The N lines are connected to each other, and the operation is switched from the router operation to the repeater operation by hardware (S3). The repeater processing unit 13 converts the frame received from the LAN line unit into another LA
The frame is transferred to the N line unit, and the frame received from the WAN line unit is transferred to another WAN line unit.

According to this embodiment, it is possible to perform routing between lines having different media even if the failed router has no media conversion function.

[0091]

As described above, according to the present invention,
The following effects can be obtained. (1) According to the first aspect of the invention, it is possible to continue the routing operation when a router fails, without arranging a plurality of routers redundantly for each subnet, and to achieve low cost reliability. Performance can be improved.

(2) According to the second aspect of the present invention, it is possible to suppress the power consumption of the router by switching to the degenerate operation by the proxy operation at the time of low traffic such as at night or on holidays.

(3) According to the third aspect of the present invention, it is possible to operate each router without setting in advance the port information required for proxy routing, thereby reducing the labor required for network construction and configuration change, and This can greatly contribute to prevention of malfunction due to a setting error.

(4) According to the fourth aspect of the present invention, switching can be performed quickly and reliably without increasing the traffic of the network, as compared with a method such as a health check.

(5) According to the fifth aspect of the invention, it is possible to perform a repeater operation even in a loop configuration, and to improve the reliability even in a mixed configuration with a redundant configuration by a plurality of routers and in a complicated network. It is possible to realize power saving.

(6) According to the invention of claim 6, WA
The repeater operation between LAN ports having different N or different speeds can be simply connected without media conversion, and cost reduction and improvement in reliability when using the router according to claim 1 can be achieved.

As described above, according to the present invention, it is possible to continue the routing operation when a router fails, without arranging a plurality of routers redundantly for each subnet, and to provide a low-cost router. Can be provided.

[Brief description of the drawings]

FIG. 1 is a principle block diagram of the present invention.

FIG. 2 is a diagram illustrating a configuration example of a network system to which the present invention is applied;

FIG. 3 is an explanatory diagram of an operation of the faulty router according to the first embodiment;

FIG. 4 is an operation flowchart of the faulty router according to the first embodiment;

FIG. 5 is an operation explanatory diagram of the proxy router of the first embodiment;

FIG. 6 is an explanatory diagram of an internal configuration of a proxy router according to the first embodiment before proxy;

FIG. 7 is a diagram showing a state of an address table of an IF of R2 during a normal operation according to the first embodiment;

FIG. 8 is a diagram illustrating a state of a routing table of R2 during a normal operation according to the first embodiment;

FIG. 9 is a diagram illustrating a routing table state of R3 during a normal operation according to the first embodiment;

FIG. 10 shows S1 ← → S3 during normal operation of the first embodiment.
It is a figure showing a communication sequence between.

FIG. 11 is an explanatory diagram of the internal configuration of a proxy router according to the first embodiment;

FIG. 12 is a diagram showing an example of the operation of R2 when an R1 failure occurs in the first embodiment
FIG. 9 is a diagram showing an address table state of F.

FIG. 13 is a diagram showing a routing table state of R2 (proxy router) when an R1 failure occurs in the first embodiment.

FIG. 14 is a diagram illustrating a state of a routing table of R3 when an R1 failure occurs according to the first embodiment;

FIG. 15 is an operation flowchart of the proxy router according to the first embodiment;

FIG. 16 shows S1 ← → in the proxy operation of the first embodiment.
It is a figure showing the communication sequence between S3.

FIG. 17 is an operation explanatory diagram of the second embodiment.

FIG. 18 is an operation flowchart of the second embodiment.

FIG. 19 is an operation explanatory diagram of the third embodiment.

FIG. 20 is an operation flowchart of the third embodiment.

FIG. 21 is an operation explanatory diagram of the fourth embodiment.

FIG. 22 is an operation flowchart of the fourth embodiment.

FIG. 23 is a diagram illustrating a network configuration according to a fifth embodiment;

FIG. 24 is an operation explanatory diagram of the fifth embodiment.

FIG. 25 is an operation flowchart of the fifth embodiment.

FIG. 26 is a diagram illustrating a network configuration example according to a sixth embodiment;

FIG. 27 is an operation explanatory diagram of the sixth embodiment.

FIG. 28 is an operation flowchart of the sixth embodiment.

FIG. 29 is a conceptual diagram of a conventional router.

FIG. 30 is a diagram showing a conventional system configuration example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 LAN line part 2 Routing processing part 3 LAN line part 4 Route information control part 10 Router 11 Mode switching trigger detection means 12 Repeater mode switching means 13 Repeater processing part 14 Other apparatus mode switching detection means 15 Routing substitution means 16 Traffic monitoring means 17 Port information acquisition means 18 Frame monitoring means for other devices 19 Loop detection means 20 Intra-media connection means

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takao Kama 2-2-1 Momichihama, Sawara-ku, Fukuoka, Fukuoka Prefecture Inside Fujitsu Kyushu Communication System Co., Ltd. No. 2 Fujitsu Kyushu Communication System Co., Ltd. F term (reference) 5K030 GA04 HC01 HC14 HD02 HD03 MB09 5K033 AA04 AA09 DA05 DB18 9A001 CC03 CC07 CC08 JJ25 JZ25 KK56 LL02 LL07 LL09

Claims (6)

[Claims] 1. A mode switching trigger detecting means for detecting an operating mode switching trigger based on a specific event in a router; a repeater mode switching means for switching a connection between ports from a router operation to a repeater operation; A repeater processing unit that connects between the ports of each other and transmits a frame received from a certain port to all other ports; another device mode switching detection unit that detects that another router has switched to the repeater mode; A router, comprising: a routing substituting means for substituting a routing function for a frame addressed to the router, and substituting a routing function of another router at a certain moment. 2. The router according to claim 1, further comprising traffic monitoring means for automatically recognizing a decrease in traffic in the device. 3. The apparatus according to claim 1, further comprising a port information acquisition unit that acquires information necessary for a routing proxy function from each router in the network using a network management protocol. The router described. 4. The router according to claim 1, further comprising a frame monitoring unit for another device, which monitors a frame for another device during operation of the router. 5. The router according to claim 1, further comprising loop detection means for recognizing a loop configuration of the network. 6. The router according to claim 1, further comprising an intra-media connection means for connecting ports of the same media when the router has a WAN or a different-speed LAN interface.