JPH06334687A - Router - Google Patents

Abstract

PURPOSE:To prevent the concentration of loads to a specific relay route without enlarging the transmission delay of an important packet. CONSTITUTION:This router 1 judges the priority of the packet corresponding to the kind of the packet to be relayed by using a packet priority judging table 4 by a router function 2. Then, based on the priority of the packet and the priority of the plural relay routes stored in a routing table 3, one relay route is selected from the plural relay routes and the packet is transmitted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a router device for interconnecting a plurality of computer networks, and more particularly to a router device for load balancing among a plurality of relay routes, detecting a faulty route and detouring.

[0002]

2. Description of the Related Art A computer network is a system in which terminals such as computers are connected to each other by an optical fiber or an electric cable, and functions such as transmission and reception of data between terminals and sharing of output devices and storage devices are realized. . A router device is one of the devices that interconnect computer networks. In a computer network interconnected by this router device, terminals on different computer networks can communicate with each other.

When one terminal sends data to another terminal, the source terminal adds the address of the source terminal and the address of the destination terminal to the data for transmission. In this way, the source and destination addresses and other information necessary for relaying are added to the data, which is called a packet. An address is an identifier for uniquely identifying a certain terminal within an interconnected computer network.

FIG. 15 shows, for example, Japanese Patent Laid-Open No. 3-234140.
FIG. 6 is a block diagram showing a configuration of a conventional router device as shown in Japanese Patent Publication No. The conventional router device 97 shown in this figure
Includes a router function 98 for performing relay processing, a routing table 99 for storing relay processing information, and local interfaces 5a to 5d for connecting the router device to a computer network. The local interfaces 5a-5d are adapted to be connected to a computer network via cables 8a-8d.

FIG. 16 is an explanatory diagram for explaining the operation of a conventional router device. As shown in this figure, the computer networks 6a to 6h are connected to router devices 97a to 97g via cables 8a to 8p, and are interconnected via this router device. Incidentally, reference numeral 7a,
7b is a terminal on a computer network.

The router device connects two or more computer networks to each other and relays packets. For this reason, it has a table called a routing table in which relay routes are recorded. FIG. 19 shows the contents of the routing table 99 of the router device 95a of FIG. In FIG. 19, each row (hereinafter referred to as an entry) forming the routing table 99 shows information on a certain relay route. The item in the first column of the routing table 99 is a destination network, which is a finally reachable computer network. Second
The item in the column is the transfer destination router device, which is the router device to which the packet should be transferred next in order to reach the destination network of this entry. The third column is the number of hops,
This is the number of router devices including itself that reach the destination network of this entry. The fourth column shows the priority among entries having the same destination network, and the smaller the number, the higher the priority. The fifth column is the update time, which indicates the time when the content of this entry was recently updated.

FIG. 17 is a flow chart showing the operation of the relay process of the router device 97 shown in FIG. Now, FIG.
In, it is assumed that the terminal 7a transmits the packet 9 addressed to the terminal 7b. The operation of the router device 97a at this time is shown in FIG.
Follow along. First, the local interface 5a
When the packet 9 is received (step (hereinafter referred to as S) 100), the router function 98 of FIG. 15 determines the final destination network from the destination address of the packet 9 (S101). Here, since the destination terminal is the terminal 7b, it is determined that the computer network 6b connected to the terminal 7b is the destination network.

Next, in order to search the routing table 99, 1 is set as the priority of the search target (S1).
02). Then, an entry in which the priority of the destination network matches the priority of the search target is searched (S103), and it is determined whether or not there is a matching entry (S104). If there is no matching entry (NO), the received packet is discarded (S1
05) Finish. Here, the destination network is the computer network 6b, and the priority of the search target is 1. Then, it matches the second entry (S104:
Yes). If there is a matching entry, it is determined whether or not the number of hops of the entry is 1 (S106).
When the number of hops is 1 (YES), it is directly transmitted to the destination terminal (S107), and the process ends (S111). Here, the number of hops of the second entry is 2 (S10
6: NO), the router device 97b that is the transfer destination router device
The packet 9 is transmitted to (S108). Next, it is determined whether or not the transmission is normally completed (S109), and if it is assumed that the transmission is normally completed (YES), the process is terminated (S11).
1).

Router device 97b which received packet 9
Determines that the final destination is the computer network 6b by checking the destination of the packet 9, searches the routing table 99 of its own, and determines that the computer network 6b is the computer network to which it is directly connected. Since it is known, the packet 9 is directly transmitted to the terminal 7b.

In the above example, if transmission from the router device 97a to the router device 97b is impossible due to, for example, a failure of the computer network 6h, it is determined that the transmission has not ended normally (S109). : N
O), the priority of the search target is lowered by 1 to 2 (S11).
0). Then, when the routing table 99 is searched (S103), it matches the third entry (S10).
4). Since the hop count of the third entry is 3, (S10
6: NO), the router device 97d that is the transfer destination router device
The packet 9 is transmitted to (S108). Here, if the transmission is normally performed (S109), the process ends (S1).
11).

One of the methods for the router device to dynamically learn the routing table is to use RIP (Routing).
Information Protocol). The operation of the RIP is performed, for example, by Kyoritsu Shuppan Co., Ltd. “Second Edition TCP / IP Network Construction Vol. I” (1
Issued December 5, 991), pages 201-206.

A method for the router device to teach the relay route information will be described below with reference to FIG. In FIG. 16, reference numerals 28a to 28c are relay route information regular notifications, and the router device 97 has the same computer network 6
Is a packet for notifying the other router device 97 connected to the router of the contents of the routing table of each router device.
In the relay route information periodical notification, for all the destination networks reachable from the source router transmission 97, the destination network and the information about how many hops it can reach are stored as a set.

FIG. 18 is a flowchart showing the operation when the router device 97 receives the relay route information regular notification. Now, the router device 97b receives the relay route information regular notification 28
Regarding the operation of the router device 97a when transmitting b,
A description will be given along the flowchart of FIG. The local interface 5a in FIG.
When a is received (S112), the router function 98 identifies the source router device from the source address of the relay route information regular notice 28a (S113). Here, it is determined that the source router device is the router device 97b. Next, each entry of the relay route reception periodical notification is examined in order (S114). Next, it is determined whether or not there is an entry (S115), and if there is no entry (NO), the process ends (S116).

Here, it is assumed that the entry having the information that the destination network is the computer network 6b and the hop number is 1 is first entered. Therefore, since there is an entry (S115: YES), the destination network is extracted from the entry of the relay route information regular notification 28a (S117). Here, it is the computer network 6b. Then, the routing table 99 is searched for an entry in which the destination network is the computer network 6b and the transfer destination router device is the router device 97b (S118). Next, it is determined whether there is a matching entry (S119). Here, 2
There is the second matching entry (S119: YE
S), the router function 98 rewrites the hop count of the second entry to the value obtained by adding 1 to the hop count in the entry of the relay route information regular notification 28a (S121), and rewrites the update time to the current time (S122). If there is no matching entry in the routing table 99 (S119: N
O) makes a new entry in the routing table 99 (S120), and proceeds to S121. Next, it is determined whether or not the hop count has changed before and after rewriting (S
123). Here, since the number of hops has not changed before and after rewriting (S123: NO), the process moves to the next entry of the relay route information regular notification 28a (S125). If the number of hops is different before and after the rewriting (S123: YES), the priority is recalculated for all entries of the same destination network (S124).
Proceed to S125. After S125, the process returns to S115, the same process is performed, the process is performed up to the last entry, and the whole process is finished (S116).

Similarly, the router device 97a receives the relay route information regular notice 28b and the relay route information regular notice 28c from the router device 97d and the router device 97g, and the third, fourth, fifth, The contents of the sixth and eighth entries are updated.

Each router device 97 normally sends the relay route information regular notice 28 to another router device every 30 seconds. If the router device 97 fails or the computer network 6 has a failure, the destination network cannot be reached through the relay route. In such a case, the relay route information periodical notification 28 also does not arrive, so the router device 97
Usually does not receive the relay route information regular notice 28 for 180 seconds, it judges that the relay route cannot be used, and sets the entry to the routing table 99.
Remove from.

[0017]

In the conventional router device as described above, even if there are a plurality of relay routes, the relay route with the highest priority is always used, and the load is concentrated on this relay route. There was a problem. Therefore, although the router devices 97c to 97g have a margin, the amount of packets exceeding the processing capability of the router device 97b is relayed to the router device 97b, and the router device 97b cannot process all the packets. There was a point.

Further, as described above, since 180 seconds is waited until it is determined that the relay route is unavailable, even if the relay route with a high priority actually becomes unavailable, it is not understood and the priority is given. There was a problem that the transmission delay time became long because the relaying was continued while the frequency was high.

In Japanese Patent Laid-Open No. 1-303832, detour type information indicating the degree of importance of a packet is added to a packet, and when the number of transmission waits is a predetermined value or more, a packet with a low level of detour type information is detoured. A technique for selecting and transmitting a packet transfer path is shown. However, even with this technique, since the route with the highest priority is always selected in order, the load is concentrated on a specific route.

Further, Japanese Laid-Open Patent Publication No. 2-203637 discloses a technique in which a priority order for selecting and using a line path at the time of making a call in a terminal is determined and connection to lines is sequentially tried in this priority order. . However, in this technique, if the priority is set in order from the smallest transmission delay time at each terminal,
After all, the load concentrates on a specific route. In order to avoid this, if the priority order is arranged differently for each terminal,
In a terminal in which a route having a large transmission delay time is set as a high priority, all packets are transmitted through the route selected according to this priority, so that there is a problem that the transmission delay time becomes large even for important packets. .

The present invention has been made in view of the above problems, and a first object thereof is to concentrate a load on a specific relay route without increasing a transmission delay time of an important packet. It is to provide a router device which can be prevented.

A second object of the present invention is to provide a router device capable of changing the priority of the relay route according to the status of the relay route.

[0023]

In order to achieve the above object, a router device of the invention according to claim 1 of the present application interconnects a plurality of computer networks for connecting a plurality of terminals to each other. In relaying packets for communication, a routing table that stores a plurality of relay routes between a source terminal and a destination terminal together with their priority, and according to the type of packet to be relayed, Packet priority determining means for determining the priority of the packet corresponding to the priority of the relay route to be selected, and priority of the relay route stored in the routing table and priority of the packet determined by the packet priority determining means And a packet transmitting unit that selects one relay route from a plurality of relay routes and transmits a packet based on the frequency. .

The router device according to a second aspect of the present invention is the router device according to the first aspect of the present invention, in which the contents of the routing table are regularly transmitted to other router devices as relay route information regular notifications. Means and a dynamic learning means for updating the contents of the routing table by receiving the relay route information regular notification from another router device, and finally after receiving the relay route information regular notification from the other router device. The elapsed time measuring means for measuring the elapsed time and the priority of the relay route passing through the corresponding router device when the elapsed time measured by the elapsed time measuring means exceeds a predetermined elapsed time determination threshold value. And a priority changing means for lowering the priority.

A router device according to a third aspect of the present invention is the router device according to the second aspect, wherein when the elapsed time measured by the elapsed time measuring means does not exceed the elapsed time determination threshold value, the corresponding router device is If the priority of the transit route is already lowered, increase the priority.
It is provided with a priority changing means.

According to a fourth aspect of the invention, in the router apparatus of the second or third aspect, the packet processing number measuring means for measuring the number of packet processings per unit time, and the packet processing number measuring means are used for measurement. And a notification interruption means for interrupting the transmission of the relay route information regular notification when the packet processing count exceeds a predetermined packet processing count determination threshold value.

A router device according to a fifth aspect of the present invention is the router device according to the first aspect of the present invention, further comprising: relay route information regular notification means for periodically transmitting the contents of the routing table to another router device as a regular relay route information notification. , A dynamic learning means for receiving the periodic notification of relay route information from another router device and updating the contents of the routing table, and the time elapsed since the last periodic notification of relay route information from another router device was received. And an elapsed time measuring means for measuring the elapsed time, and a relay path use for prohibiting the use of the relay path passing through the corresponding router device when the elapsed time measured by the elapsed time measuring means exceeds the elapsed time determination threshold value. It is provided with a prohibition means.

[0028]

According to the invention described in claim 1, the packet priority determining means determines the priority of the packet corresponding to the priority of the relay route to be selected according to the type of the packet to be relayed. On the basis of the priority of the relay route and the priority of the relay route stored in the routing table, the packet transmitting unit selects one relay route from the plurality of relay routes and transmits the packet.

According to the second aspect of the invention, the elapsed time measuring means measures the elapsed time since the last reception of the relay route information regular notification from the other router device, and this elapsed time is the predetermined elapsed time. When the judgment threshold is exceeded, the priority changing unit lowers the priority of the relay route passing through the corresponding router device.

According to the third aspect of the invention, when the elapsed time measured by the elapsed time measuring means does not exceed the elapsed time determination threshold value, the priority of the relay route passing through the corresponding router device is already lowered. If so, the second priority changing means raises the priority.

According to the invention described in claim 4, the packet processing number measuring means measures the packet processing number per unit time, and when the packet processing number exceeds a predetermined packet processing number determination threshold value, a notification is given. By means of interruption
Transmission of the relay route information regular notification is interrupted.

According to the fifth aspect of the present invention, when the elapsed time measured by the elapsed time measuring means exceeds the elapsed time determination threshold value, the relay route use prohibiting means causes the relay route passing through the corresponding router device. Is prohibited.

[0033]

EXAMPLES Examples of the present invention will be described in detail below. 1 to 5 relate to a first embodiment of the present invention.

FIG. 1 is a block diagram showing the configuration of the router device of this embodiment. The router device 1 according to the present exemplary embodiment includes a router function 2 that performs relay processing, a routing table 3 that stores relay processing information, and a packet priority determination table 4.
And local interfaces 5a to 5d for connecting the router device to the computer network. The local interfaces 5a to 5d are cables 8a
8d to be connected to a computer network. Routing table 3, packet priority determination table 4 and local interface 5
a to 5d are connected to the router function 2. The router function 2 is composed of a computer and a storage device that stores programs executed by the computer, necessary data, and the like, and has functions of a packet priority determination unit and a packet transmission unit.

FIG. 2 is an explanatory diagram for explaining the operation of the router device of this embodiment. In this figure, reference numerals 1a to
Reference numeral 1g is the router device of this embodiment, and the rest of the configuration is similar to that of FIG.

In the following description, it is assumed that a sufficient time has passed since the router devices 1a to 1g started operating. The contents of the routing table 3 of the router device 1a in this state are shown in FIG. In FIG. 4, each row forming the routing table 3 (hereinafter referred to as an entry)
Indicates information about a relay route. In this embodiment, the routing table 3 has 10 entries. The meaning of each column of the routing table 3 is
The description is omitted because it is similar to FIG. 19.

In this embodiment, the packet priority is
The type of packet called telnet has the highest priority, the priority is 1, the next is the packet called FTP, the priority is 2, the next is the packet called ICMP, the priority is 3, and the others are priority 4. The contents of the packet priority determination table 4 under this condition are shown in FIG. In FIG. 5, each row (hereinafter referred to as an entry) forming the packet priority determination table indicates a certain packet type and its priority. Packet priority determination table 4
The first column of is the packet type, and the second column is the priority of the packet type. The smaller the number, the higher the priority.

Next, the operation of the router device of this embodiment will be described with reference to the flowchart of FIG.

In the router device 1, when the local interface receives the packet (S10), the router function 2 determines the packet type (S11) and searches the packet priority determination table 4 (S12). Then, it is determined whether or not there is a matching entry in the packet priority determination table 4 (S13), and if there is (YES), the priority of the received packet is set as the priority of the matching entry (S1).
4) If not (S13: NO), the priority of the received packet is set to a value obtained by adding 1 to the number of entries in the packet priority determination table (S15).

Next, the destination network is judged from the destination address of the received packet (S16), and the routing table 3 is searched in the destination network (S17). Then, it is judged whether or not there is a matching entry in the routing table 3 (S18), and if there is no matching entry (NO), the received packet is discarded (S19) and the process is terminated. If there is a matching entry (S18: YES), it is determined whether or not there is an entry having a priority matching the priority of the received packet (S20). If there is (YES), the entry is selected (S21), and if there is no (S20: NO).
Among the entries having a higher priority than the priority of the received packet, the entry having the highest priority is selected (S22). Next, it is determined whether the number of hops of the entry selected in S21 or S22 is 1 (S23),
When the number of hops is 1 (YES), it is directly transmitted to the destination terminal (S24) and the processing is finished (S26). When the number of hops is not 1 (S23: NO), it is transmitted to the transfer destination router device. (S25) The process ends (S26).

Next, the terminal 7a sends telne to the terminal 7b.
The operation of the router transmission 1a when the packet of t is transmitted will be specifically described. In this case, when the local interface 5a receives the packet 9 (S10), the router function 2 checks the type of the packet 9 and determines that it is a telnet packet (S11). Next, the packet priority determination table 4 is searched for telnet (S1
2) Match on the first entry. Since there is a matching entry (S13: YES), it is determined that the priority of the packet 9 is the priority of the first entry, that is, 1 (S14).

Next, the router function 2 determines from the destination address of the packet 9 that the final destination is the computer network 6b (S16), and searches the routing table 3 for the computer network 6b as the destination network (S17). . Then, the destination network 6b matches the second to fourth entries. Since there is a matching entry (S18: YES), packet 9
For an entry having the same priority as the priority of (S20)
Then, since the priority of the packet 9 is 1, the second entry of the routing table 3 is selected (S21). Since the hop count of the second entry is 2, the packet 9 is transmitted to the router device 1b which is the transfer destination router device (S2
5), the process ends (S26).

The router device 1b receiving the packet 9
Since the destination of the packet 9 is checked to determine that it is the final destination computer network 6b and the routing table 3 is searched for, the computer network 6b is found to be the computer network to which it is directly connected. 9 directly to the terminal 7b.

Next, the terminal 7a sends telne to the terminal 7b.
The operation of the router device 1a when a packet other than t, FTP, and ICPM is transmitted will be specifically described. Here, it is assumed that a packet called TFTP is transmitted as an example. In this case, the local interface 5a
When the packet 9 receives the packet 9 (S10), the router function 2 checks the type of the packet 9 and determines that the packet is a TFTP packet (S11). Then, the packet priority determination table 4 is searched for TFTP (S12), and the fourth entry is matched. Since there is a matching entry (S13: YE
S), the priority of the packet 9 is determined to be the priority of the fourth entry, that is, 4 (S14).

Next, the router function 2 determines from the destination address of the packet 9 that the final destination is the computer network 6b (S16), and searches the computer network 6b as the destination network in the routing table 3 (S17). . Then, the destination network 6b matches the second to fourth entries. Since there is a matching entry (S18: YES), packet 9
For an entry having the same priority as the priority of (S20)
Then, since there is no matching entry (NO), the entry with the priority lower than the priority 4 and the lowest priority is searched, and the entry with the priority 3 is found. Since this entry is the fourth entry in the routing table 3, the fourth entry is selected (S22). Since the hop count of the fourth entry is 4, the router device 1 which is the transfer destination router device
The packet 9 is transmitted to g (S25), and the process ends (S26).

The router device 1g receiving the packet 9
The packet 9 is transmitted to the router device 1f by the same procedure, and the router device 1f performs the router device 1e by the same procedure.
Packet 9 is transmitted to The router device 1e receives the packet 9
Is determined to be the final destination computer network 6b, and its own routing table 3
And finds that the computer network 6b is the computer network to which it is directly connected, the packet 9 is directly transmitted to the terminal 7b.

As described above, according to the present embodiment, the packet priority determination table 4 determines the packet priority according to the type of the packet to be relayed, and the priority of the relay route stored in the routing table 3 is given. The relay route to which the packet is transmitted is determined together with the frequency, so that the load is distributed and the concentration of the load on the specific relay route can be prevented.

Since the priority of the packet is determined according to the type of packet, the transmission delay of the important packet can be reduced by making the priority of the important packet higher.

6 to 8 relate to the second embodiment of the present invention. In the present embodiment, when the relay route information regular notification from another router device is delayed, the priority of the relay route passing through the router device is lowered.

FIG. 6 is a block diagram showing the configuration of the router device of this embodiment. The router device 1 of the present embodiment is provided with an elapsed time measuring device 27 that is connected to the router function 2 and that measures the elapsed time after receiving the relay route information regular notification from another router device. In addition to the function of the first embodiment, the router function 2 includes relay route information regular notification means,
It has the functions of dynamic learning means and priority changing means. Other configurations are similar to those of the first embodiment.

FIG. 7 is an explanatory diagram for explaining the operation of transmitting and receiving the relay route information regular notice of the router device of this embodiment. In this figure, reference numeral 28 is a relay route information regular notification transmitted from the router device 1b to the router device 1a. Other configurations are the same as those in FIG.

In the following description, it is assumed that a sufficient time has passed since the router devices 1a to 1g started operating. The contents of the routing table 3 of the router device 1a in this state are as shown in FIG. Further, in the present embodiment, for example, it is assumed that the elapsed time determination threshold value is set to 40 seconds. Further, the router device 1 is assumed to transmit the relay route information regular notification 28 to other router devices 1 every 30 seconds.

Now, the router device 1b is the last router device 1
It is assumed that 41 seconds have passed since the relay route information regular notification was transmitted to a at 10: 51: 5. In FIG. 4, the update time of the second entry in the routing table 3 is 10: 51: 5 when the router device 1a receives the previous relay route information regular notice 28 from the router device 1b.

FIG. 8 is a flow chart showing the operation of the router function 2 involved in changing the priority in this embodiment.

The router function 2 regularly checks the contents of the routing table 3. Here, it is assumed that the check is performed every one second, for example. Router function 2 is 1
The routing table 3 is examined in order from the second entry (S29). Next, it is determined whether or not there is an entry (S30), and if there is no entry (NO), the process ends (S30).
31). If there is an entry (S30: YES), it is determined whether or not the hop count of the corresponding entry is greater than 1 (S32). When the number of hops is not greater than 1 (NO)
Moves the processing to the next entry (S40) and returns to S30. When the number of hops is larger than 1 (S32: YES)
Calculates the elapsed time by subtracting the update time of the corresponding entry from the current time (S33).

Next, it is determined whether or not the elapsed time exceeds the elapsed time determination threshold value (S34). If it does not exceed (NO), the process moves to the next entry (S40).
If it exceeds (S34: YES), the priority of the corresponding entry is decremented by 1 (S35). Next, an entry having the same priority as the corresponding entry in the same destination network is searched (S36). Next, it is determined whether or not there is an entry (S37). If there is (YES), the priority of the matching entry is increased by 1 (S38). If there is no (S37: NO), the priority of the corresponding entry in S30 is set. Increase 1 (S3
9) and moves to the next entry (S40).

Here, the operation of the router function 2 will be specifically described with reference to FIG. 8 in the case where the routing table 3 has the contents shown in FIG. The router function 2 examines the routing table 3 in order from the first entry (S29). First, since there is the first entry (S30: YES), looking at the first hop count (S3
2) There is no need to check because the hop count is 1 (N
O), and moves the processing to the next entry (S40).

The router function 2 next checks the second entry. Since the number of hops of the second entry is 2 and is larger than 1 (S32: YES), the router function 2 causes the elapsed time measuring device 27 to determine the elapsed time after receiving the previous relay route information regular notification 28. Calculate (S3
3). The current time is 10:51:46 and the update time is 1
Since it is 0: 51: 5, the elapsed time is 41 seconds. When this elapsed time is compared with the elapsed time determination threshold value (S3
4), the elapsed time determination threshold value is 40 seconds, and the elapsed time exceeds the elapsed time determination threshold value (YES). Therefore, the router function 2 performs the process of lowering the priority of the second entry as follows.

First, the priority of the second entry is lowered by 1 to 1 from 2 (S35). Then, the same destination network is searched for an entry having a priority of 2 (S36). Since the third entry matches (S3
7: YES) Increase the priority of the third entry by 1,
Change from 2 to 1 (S38). As a result, the second to fourth destination networks are the computer networks 6b.
The priorities of the 3rd entry are changed from 1, 2, and 3 to 2, 1, and 3, respectively.

After this, the processing is performed for the third and subsequent entries, the last entry is scrutinized, and the processing is terminated (S31).

As described above, according to the present embodiment, the elapsed time since the last reception of the relay route information periodical notification is measured, and when this elapsed time exceeds the threshold value, the corresponding relay Since the priority of the route is lowered, it becomes possible to preferentially use other relay routes after that.
It is possible to prevent an increase in transmission delay time.

Other functions and effects are similar to those of the first embodiment.

9 to 11 relate to the third embodiment of the present invention. In this embodiment, when the relay route information regular notification from another router device arrives before the elapsed time determination threshold value is reached, the priority of the relay route passing through the router device is already lowered. In addition, the priority is raised.

The configuration of the router device of this embodiment is the same as that of the second embodiment shown in FIG. 6, but the router function 2 is the function of the second priority changing means in addition to the function of the second embodiment. have.

In the following description, it is assumed that a sufficient time has passed since the router devices 1a to 1g started operating. FIG. 11 shows the contents of the routing table 3 of the router device 1a in this state. In FIG. 11, the first to fifth columns are the same as those in FIG. The sixth column is the priority decrease number, and a positive number greater than 0 when the priority of this entry has fallen from the original priority, and less than 0 when it has risen from the original priority. It has a negative value, and its absolute value shows the difference from the original priority.

In the present embodiment, for example, it is assumed that the elapsed time determination threshold value is set to a value of 40 seconds. Further, the router device 1 is assumed to transmit the relay route information regular notification 28 to other router devices 1 every 30 seconds.

FIG. 9 is a flow chart showing the operation when the router device 1 receives the relay route information regular notification.
When the local interface receives the relay route information regular notice 28 (S41), the router function 2 identifies the source router device from the source address of the relay route information regular notice 28 (S42). Next, each entry of the relay route information periodical notice 28 is examined in order (S43), it is determined whether there is an entry (S44), and if there is no entry (NO), the process ends (S45). If there is an entry (S44: YES), the destination network is extracted from the entry of the relay route information regular notification 28 (S46),
In the routing table 3, an entry in which the destination network matches and the transfer destination router device is the source router device is searched (S47), and it is determined whether there is a matching entry (S48). If there is a matching entry (S48: YES), the update time of the entry is subtracted from the current time to calculate the elapsed time (S49), and it is determined whether the elapsed time is less than or equal to the elapsed time determination threshold value. (S
51). When the elapsed time judgment threshold value or less (YES)
Determines whether or not the priority reduction number of the corresponding entry is greater than 0 (S52). If greater than 0 (S51: Y
ES) raises the priority of the corresponding entry by 1 (S53),
The priority reduction number of the corresponding entry is decremented by 1 (S54).

Then, an entry having the same priority as the corresponding entry in the same destination network is searched (S5).
5) It is determined whether there is an entry (S56). If there is an entry (YES), the priority of the matching entry is decreased by 1 (S57), and the priority reduction number of the matching entry is decreased by 1.
Increase (S58). Next, the number of hops in the routing table 3 is rewritten with the number of hops + 1 in the relay route information regular notification 28 (S59), and the update time is rewritten to the current time (S60). Next, it is determined whether the number of hops has changed (S61). If the number of hops has changed (YE
In S), the priority is recalculated for all entries of the same destination network (S62), and the process proceeds to the next entry (S).
63) and returns to S44. If the number of hops has not changed (S61: NO), the process directly proceeds to the next entry (S6).
3).

If there is no entry in S48 (N
O) creates a new entry (S50) and proceeds to S59. If the elapsed time is greater than the elapsed time determination threshold value in S51 (NO), the priority reduction number of the corresponding entry is 0 or less in S52 (NO), and the entry has no entry in S56 (NO), Then, the process proceeds to S59.

FIG. 10 is a flow chart showing the operation of the router function 2 involved in changing the priority in this embodiment.

The router function 2 regularly checks the contents of the routing table 3. Here, it is assumed that the check is performed every one second, for example. Router function 2 is 1
The routing table 3 is examined in order from the second entry (S64). Next, it is judged whether or not there is an entry (S65), and if there is no entry (NO), the processing is ended (S65).
66). When there is an entry (S65: YES), it is determined whether or not the hop count of the corresponding entry is larger than 1 (S67). When the number of hops is not greater than 1 (NO)
Moves the processing to the next entry (S78) and returns to S65. When the number of hops is larger than 1 (S67: YES)
Calculates the elapsed time by subtracting the update time of the corresponding entry from the current time (S68).

Next, it is determined whether or not the elapsed time exceeds the elapsed time determination threshold value (S69). If not exceeded (NO), the process moves to the next entry (S78).
When it exceeds (S69: YES), the priority of the corresponding entry is decreased by 1 (S70), and the priority reduction number of the corresponding entry is increased by 1 (S71). Next, an entry having the same priority as the corresponding entry in the same destination network is searched (S72). Next, it is determined whether or not there is an entry (S73), and if there is (YES), the priority of the matching entry is increased by 1 (S74), and the number of decrease in the priority of the matching entry is decreased by 1 (S76). Move to entry (S78).
If there is no entry (S73: NO), the priority of the corresponding entry in S65 is increased by 1 (S75), the number of decrease in the priority of the corresponding entry is reduced by 1 (S77), and the process moves to the next entry (S78).

Here, the operation when the elapsed time exceeds the elapsed time determination threshold value will be specifically described with reference to FIG.

It is assumed that 41 seconds have passed since the router apparatus 1b previously transmitted the relay route information regular notification to the router apparatus 1a at 10: 51: 5. In FIG. 11, the update time of the second entry in the routing table 3 is 10: 51: 5 when the router device 1a receives the previous relay route information regular notification 28 from the router device 1b.

The router function 2 examines the routing table 3 in order from the first entry (S64).
First, since there is the first entry (S65: YE
S) Looking at the first hop count (S67), since the hop count is 1, there is no need to check (NO), and the process moves to the next entry (S78).

The router function 2 next checks the second entry. Since the hop count of the second entry is 2 and is larger than 1 (S67: YES), the router function 2 causes the elapsed time measuring device 27 to determine the elapsed time after receiving the previous relay route information regular notification 28. Calculate (S6
8). The current time is 10:51:46 and the update time is 1
Since it is 0: 51: 5, the elapsed time is 41 seconds. When this elapsed time is compared with the elapsed time determination threshold value (S6
9), the elapsed time determination threshold value is 40 seconds, and the elapsed time exceeds the elapsed time determination threshold value (YES). Therefore, the router function 2 performs the process of lowering the priority of the second entry as follows.

First, the priority of the second entry is lowered by 1 to 1 to 2 (S70). Then, since the priority is lowered by 1, the priority reduction number is increased by 1 to change from 0 to 1 (S71). Then, the same destination network is searched for an entry having a priority of 2 (S72). Since the third entry matches (S73: YES), the priority of the third entry is increased by 1 to be changed from 2 to 1 (S7).
4). Then, since the priority is increased by 1, the priority decrease number is decreased by 1 to change from 0 to -1 (S76). As a result,
The priorities of the three entries from the second to the fourth with the destination network being the computer network 6b are 1, 2, and 3 respectively, but are changed to 2, 1, and 3 respectively. Further, the priority reduction numbers of the respective entries are 0, 0, 0, but become +1, -1, 0.

Next, FIG. 9 shows the operation when the router apparatus 1a receives the relay route information regular notification at 10:51:50 and 10:52:20 from the router apparatus 1b after the above processing. A specific description will be made with reference.

First, the router device 1b is at 10:51:50.
The operation of the router device 1a when the relay route information regular notification 28 is transmitted every second will be described. When the local interface 5a receives the relay route information regular notice 28 (S
41), the router function 2 identifies the source router device from the source address of the relay route information regular notice 28 (S4).
2). Here, the source router device is determined to be the router device 1b. Next, each entry of the relay route information regular notice 28 is examined in order (S43). Here, it is assumed that the entry having the information that the destination network is the computer network 6b and the hop number is 1 is first entered.

Since there is an entry (S44: YES),
The destination network is extracted from the entry of the relay route information regular notification 28 (S46). Here, it is the computer network 6b. Then, in the routing table 3, the destination network is the computer network 6
b, and the forwarding router device searches for an entry whose router device is 1b (S47). Then, it matches the second entry. There is an entry (S48: YE
S), the router function 2 calculates the elapsed time by the elapsed time measuring device 27 (S49). The current time is 10:51 5
Since the update time is 0: 51: 5 at 0 seconds, the elapsed time is 45 seconds.

Next, comparing this elapsed time with the elapsed time determination threshold value, the elapsed time determination threshold value is 40 seconds, and the elapsed time exceeds the elapsed time determination threshold value (S
51: NO). Therefore, the router function 2 rewrites the hop number to a value obtained by adding 1 to the hop number in the entry of the relay route information regular notification 28 without changing the second entry (S59), and the update time is 10:51 of the current time. The time is rewritten to 50 seconds (S60). Since the number of hops does not change before and after rewriting here (S61: NO), the process moves to the next entry of the relay route information regular notification 28 (S6).
3). Thereafter, similar processing is performed, and when the last entry is reached, the processing ends (S45).

Then, the router device 1b switches to 10:52
The operation of the router device 1a when the relay route information regular notification 28 is transmitted at 0 seconds will be described. The local interface 5a receives the relay route information regular notification 28 (S4
After 1), the router function 2 calculates the elapsed time (S
Up to 49), the description is omitted because it is the same as the previous reception of the relay route information regular notification 28. This time, the current time is 10:52:20 and the update time is 10:51:50, so the elapsed time is 30 seconds.

Next, comparing this elapsed time with the elapsed time determination threshold value, the elapsed time determination threshold value is 40 seconds, and the elapsed time does not exceed the elapsed time determination threshold value (S51: YES). . Therefore, the router function 2 checks the priority reduction number of the second entry (S52). Since the priority reduction number includes +1 in the previous process, it is determined to be greater than 0 (S52: YES), and the process of increasing the priority of this entry is performed. Therefore, the priority of this entry is first increased by 1 and rewritten from 2 to 1 (S53). Then, the priority reduction number is decremented by 1 and rewritten from +1 to 0 (S54). Then, the same destination network is searched for an entry having a priority of 1 (S5).
5). Since the third entry matches (S56), 3
The priority of the second entry is lowered by 1 and rewritten from 1 to 2 (S57). Then, the number of decrease in priority is increased by 1 and -1
Is rewritten to 0 (S58). As a result, the priorities of the three entries from the second to the fourth with the destination network being the computer network 6b are changed to 1, 2, and 3 from 2, 1 and 3 respectively. In addition, the priority reduction number of each entry is 0.

Then, the hop count is rewritten to a value obtained by adding 1 to the hop count in the entry of the relay route information periodical notice 28 (S59), and the update time is rewritten to the current time of 10:52:20 (S60). Since the number of hops does not change before and after rewriting here (S61: NO), the process moves to the next entry of the relay route information regular notification 28 (S6).
3). Thereafter, similar processing is performed, and when the last entry is reached, the processing ends (S45).

As described above, according to this embodiment, when the relay route information regular notification regarding the relay route whose priority is already lowered is received without delaying from the threshold value,
The priority can be raised and returned to the original priority.

12 and 13 relate to the fourth embodiment of the present invention. In this embodiment, when the number of packets processed per unit time exceeds the packet processing number determination threshold value, the transmission of the relay route information notification is suspended.

FIG. 12 is a block diagram showing the configuration of the router device of this embodiment. As shown in this figure, in this embodiment, a packet processing number measuring device 79 for measuring the packet processing number per unit time is provided. The packet processing number measuring device 79 is connected to the router function 2 and the local interfaces 5a to 5d. Further, the router function 2 in this embodiment has a function of a notification interruption means in addition to the function in the second embodiment or the third embodiment. Other configurations are similar to those of the second or third embodiment shown in FIG.

In the present embodiment, for example, it is assumed that a value of 100 packets / sec is set as the packet processing number determination threshold value.

FIG. 13 is a flowchart showing the operation when the router function 2 transmits a relay route information regular notice. In this operation, first, the router function 2 creates the relay route information regular notification 28 for transmission (S80). Next, the output of the packet processing number measuring device 79 is referred to (S81).
Next, it is determined whether the packet processing number exceeds the packet processing number determination threshold relay (S82). If not exceeded (NO), the router function 2 transmits the relay route information regular notification 28 as it is (S83), and ends the process. When it exceeds (S82: YES), the router function 2 stops the transmission of the relay route information regular notice 28 (S8).
4), the process ends.

As an example, when the router device 1b tries to send the relay route information regular notice 28 to the router device 1a, the output of the packet processing number measuring device 79 is 50 packets /
If it is seconds, this is 1 of the packet processing count judgment threshold value.
Since it does not exceed 00 packets / sec (S82: N
O), the router function 2 is as it is, the relay route information regular notification 2
8 is transmitted to the router device 1a (S83).

If the output of the packet processing number measuring device 79 is 110 packets / sec when the router device 1b tries to send the relay route information regular notice 28 to the router device 1a, this is the packet processing number determination. Threshold 100
Since the packet / second is exceeded (S82: YES), the router function 2 notifies the router device 1 of the relay route information regular notification 28.
The transmission to the address a is stopped (S84).

The router device 1b uses the relay route information regular notification 2
When the transmission of 8 is stopped, the priority of the relay route passing through the router 1b is lowered in the router 1a.

As described above, according to this embodiment, when the load on the router device increases, the transmission of the relay route information regular notice is interrupted, and the load can be reduced.

Other functions and effects are the same as those in the second or third embodiment.

Next, a fifth embodiment of the present invention will be described. In this embodiment, when the relay route information regular notification from another router device is delayed, the relay route passing through the router device is disabled.

The configuration of the router device of this embodiment is the same as that of FIG. 6, but the router function 2 of this embodiment has a relay route information regular notification means and a dynamic learning means in addition to the functions of the first embodiment. It also has the function of a relay route use prohibition means. Other configurations are similar to those of the second embodiment.

In the following description, it is assumed that a sufficient time has passed since the router devices 1a to 1g started operating. The contents of the routing table 3 of the router device 1a in this state are as shown in FIG. Further, in the present embodiment, a value of 40 seconds is set as the elapsed time determination threshold value, and the router device 1 transmits the relay route information regular notice 28 to other router devices 1 every 30 seconds. .

FIG. 14 is a flow chart showing the operation of the router function 2 in this embodiment. The router function 2 regularly checks the contents of the routing table 3. As shown in FIG. 14, the router function 2 examines the routing table 3 in order from the first entry (S85). Then, it is determined whether or not there is an entry (S86), and if there is no entry (NO), the process is terminated (S8).
7). If there is an entry (S86: YES), it is determined whether or not the hop count of the corresponding entry is larger than 1 (S8).
8) If not (NO), move to the next entry (S96) and return to S86. If the hop count of the corresponding entry is greater than 1 (S88: YES), the elapsed time is calculated by subtracting the update time of the corresponding entry from the current time (S89).

Next, it is determined whether or not the elapsed time exceeds the elapsed time determination threshold value (S90), and if not (NO), the process moves to the next entry (S96). When it exceeds (S90: YES), an entry having the same destination network as the corresponding entry is searched (S91).
Next, it is determined whether there is an entry (S92), and if there is (YES), the priority of the matching entry is increased by 1 (S92).
93), move to the next entry (S94), and return to S92. If there is no matching entry in S92 (NO), S8
The corresponding entry in No. 6 is deleted from the routing table 3 (S95), and the next entry is moved to (S96).

Here, when 41 seconds have passed since the router apparatus 1b last transmitted the relay route information regular notice 28 to the router apparatus 1a at 10: 51: 5, the router apparatus 1a.
The operation of the router function 2 will be specifically described.

The router function 2 scrutinizes the routing table 3 in order from the first entry (S8).
5). First, since there is the first entry (S86: Y
ES) Looking at the hop count of the first entry (S8
8) Since the number of hops is 1, there is no need to check and the process moves to the next entry (S96).

The router function 2 next checks the second entry. Since the hop count of the second entry is 2 and is larger than 1 (S88: YES), the router function 2 causes the elapsed time measuring device 27 to determine the elapsed time since the last relay route information regular notification 28 was received. Calculate (S8
9). The current time is 10:51:46 and the update time is 1
Since it is 0: 51: 5, the elapsed time is 41 seconds. When this elapsed time is compared with the elapsed time determination threshold value (S9
0), the elapsed time determination threshold value is 40 seconds, and the elapsed time exceeds the elapsed time determination threshold value. Therefore, the router function 2 performs the work of deleting the second entry.

First, an entry having the same destination network is searched (S91). Since the third entry matches first (S92: YES), the priority of the third entry is increased by 1 to 2 to 1 (S93). When the process moves to the next entry (S94), the fourth entry also matches (S92: YES), and the priority of the fourth entry is increased by 1 to 3 to 2 (S93). Further, the next entry is processed (S94), but there is no other matching entry (S92), the second entry which is the first corresponding is deleted from the routing table 3, and
The process for the second entry ends.

After this, the third and subsequent entries are processed, and the whole processing is terminated (S87). As a result of this process,
There are only two entries of which the destination network is the computer network 6b, that is, the second and third entries, and the respective priorities were 2, 3 but are changed to 1, 2.

As described above, according to this embodiment, when the relay route information regular notification is received after the threshold value is delayed, the corresponding relay route is disabled so that the router device with a heavy load can be obtained. You can avoid the relay of.

When the relay route information regular notification is received and there is no corresponding entry in the routing table 3, a new entry is created in the same manner as S50 in FIG.

Further, similarly to the fourth embodiment, the transmission of the relay route information regular notice may be interrupted when the number of packets processed per unit time exceeds the threshold value.

[0108]

As described above, according to the invention described in claim 1, one relay route is selected from a plurality of relay routes based on the priority of the packet and the priority of the relay route according to the type of the packet. Since this is selected, it is possible to prevent the concentration of the load on a specific relay route without increasing the transmission delay time of important packets.

According to the second aspect of the invention, when the elapsed time since the last reception of the relay route information periodical notification from the other router device exceeds the threshold value, the corresponding router device is Since the priority of the relay route passing through the relay route is lowered, the priority of the relay route is changed according to the situation of the relay route to prevent an increase in transmission delay time, in addition to the effect of the invention of claim 1. There is an effect that can be done.

According to the third aspect of the invention, when the elapsed time from the last reception of the relay route information periodical notification from the other router device does not exceed the threshold value, the corresponding router device is Since the priority is increased when the priority of the relay route passing through the is already lowered, in addition to the effect of the invention according to claim 2, the priority of the normal relay route is changed to the original priority. The effect is that it can be returned.

Further, according to the invention of claim 4, the transmission of the relay route information regular notice is interrupted when the number of processed packets exceeds the threshold value. Therefore, the invention of claim 2 or 3 In addition to the above effect, there is an effect that when the load on the router device increases, the transmission of the relay route information regular notification is interrupted to reduce the load.

Further, according to the invention described in claim 5, when the elapsed time from the last reception of the relay route information periodical notification from the other router device exceeds the threshold value, the corresponding router device is Since the use of the relay route passing through is prohibited, there is an effect that it is possible to avoid relaying to a router device having a high load or a relay route having an abnormality in addition to the effect of the invention of claim 1.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a router device according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram illustrating an operation of the router device according to the first embodiment of this invention.

FIG. 3 is a flowchart showing an operation of a router function according to the first exemplary embodiment of the present invention.

FIG. 4 is an explanatory diagram showing contents of a routing table according to the first embodiment of this invention.

FIG. 5 is an explanatory diagram showing the contents of a packet priority determination table according to the first embodiment of this invention.

FIG. 6 is a block diagram showing a configuration of a router device according to a second exemplary embodiment of the present invention.

FIG. 7 is an explanatory diagram for explaining the operation of the router device according to the second embodiment of the present invention.

FIG. 8 is a flowchart showing an operation of a router function in the second exemplary embodiment of the present invention.

FIG. 9 is a flowchart showing an operation when the router device of the third exemplary embodiment of the present invention receives a relay route information regular notification.

FIG. 10 is a flowchart showing an operation of a router function in the third exemplary embodiment of the present invention.

FIG. 11 is an explanatory diagram showing contents of a routing table in the third embodiment of the present invention.

FIG. 12 is a block diagram showing a configuration of a router device according to a fourth exemplary embodiment of the present invention.

FIG. 13 is a flowchart showing an operation of a router function in the fourth exemplary embodiment of the present invention.

FIG. 14 is a flowchart showing an operation of a router function in the fifth embodiment of the present invention.

FIG. 15 is a block diagram showing a configuration of a conventional router device.

FIG. 16 is an explanatory diagram showing an example of the operation of a conventional router device.

FIG. 17 is a flowchart showing an operation of a router function in a conventional router device.

FIG. 18 is a flowchart showing an operation of a router function in a conventional router device.

FIG. 19 is an explanatory diagram showing the contents of a routing table in a conventional router device.

[Explanation of symbols]

 1 router device 2 router function 3 routing table 4 packet priority judgment table

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] August 2, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0037

[Correction method] Change

[Correction content]

In this embodiment, the packet priority is
The type of packet called telnet has the highest priority, the priority is 1, the next is the packet called FTP, the priority is 2, the next is the packet called ICMP, the priority is 3, and the others are priority 4. The contents of the packet priority determination table 4 under this condition are shown in FIG. In FIG. 5, each row (hereinafter referred to as an entry) forming the packet priority determination table indicates a certain packet type and its priority. Packet priority determination table 4
The first column of a packet type, the second column indicates the priority of the packet type, a higher priority smaller number.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0041

[Correction method] Change

[Correction content]

Next, the terminal 7a sends telne to the terminal 7b.
The operation of the router device 1a when the packet of t is transmitted will be specifically described. In this case, when the local interface 5a receives the packet 9 (S10), the router function 2 checks the type of the packet 9 and determines that it is a telnet packet (S11). Next, the packet priority determination table 4 is searched for telnet (S1
2) Match on the first entry. Since there is a matching entry (S13: YES), it is determined that the priority of the packet 9 is the priority of the first entry, that is, 1 (S14).

[Procedure 3]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 5

[Correction method] Change

[Correction content]

[Figure 5]

[Procedure amendment 4]

[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 17

[Correction method] Change

[Correction content]

FIG. 17

Claims (5)

[Claims] 1. A router device for interconnecting a plurality of computer networks for connecting a plurality of terminals and relaying a packet for communication between terminals, wherein a plurality of relay paths between a source terminal and a destination terminal are provided. A routing table stored together with the priority of the relay route, a packet priority determination means for determining the priority of the packet corresponding to the priority of the relay route to be selected according to the type of the packet to be relayed, Based on the priority of the relay route stored in the routing table and the priority of the packet determined by the packet priority determination means, one relay route is selected from a plurality of relay routes and the packet is transmitted. A router device comprising: a packet transmission unit. 2. A relay route information regular notification means for periodically transmitting the contents of a routing table to another router device as a regular relay route information notification, and routing by receiving a relay route information regular notification from another router device. The dynamic learning means for updating the contents of the table, the elapsed time measuring means for measuring the elapsed time since the last reception of the relay route information periodic notification from another router device, and the elapsed time measuring means for measuring the elapsed time. The priority changing means for lowering the priority of a relay route passing through a corresponding router device when the elapsed time exceeds a predetermined elapsed time determination threshold value. Router equipment. 3. When the elapsed time measured by the elapsed time measuring means does not exceed an elapsed time determination threshold value,
3. The router device according to claim 2, further comprising second priority changing means for increasing the priority when the priority of the relay route passing through the corresponding router device is already lowered. 4. A packet processing number measuring means for measuring the number of packet processings per unit time, and when the packet processing number measured by the packet processing number measuring means exceeds a predetermined packet processing number judging threshold value. 4. The router device according to claim 2, further comprising: a notification interrupting unit that interrupts transmission of the relay route information regular notification. 5. A relay route information regular notification means for periodically transmitting the contents of a routing table to another router device as a relay route information regular notification, and a relay route information periodic notification from another router device for receiving and routing. The dynamic learning means for updating the contents of the table, the elapsed time measuring means for measuring the elapsed time since the last reception of the relay route information periodic notification from another router device, and the elapsed time measuring means for measuring the elapsed time. The relay route use prohibition means for prohibiting the use of the relay route passing through the corresponding router device when the elapsed time exceeds the elapsed time determination threshold value. Router equipment.