JP2001189750A - Path controlling method, method for preparing path control table, path control table and router - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a path controlling method and a path control table preparing method which can easily prepare a path control table, cope with the increase of a network and have a learning function and to provide the path control table and a router. SOLUTION: This table accumulates the number of hop limits of a pass packet for each direction of addresses of a network. Looking at results obtained by accumulating the number of hop limits of the packet of a network address A, the number of hop limits is 50 from a direction R1, the number of hop limits from a direction R2 is zero, and the number of hop limits from a direction R3 is 121, etc. Because the number of hop limits is the largest in the direction R3 by 121, the probability that a received packet to the network address A exists in the direction R3 is the highest, so the received packet to the network address A is transferred to the direction R3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a routing control method, a routing control table creation method, a routing control table, and a router, and more particularly to a routing control method having a simple learning function, a routing control table creation method, and a routing control table. And routers.

[0002]

2. Description of the Related Art Conventional route control methods include a distance vector type and a link state type. The distance vector type is RI
P (Routing Information Pro
tocol). The link state type is O
SPF (Open Shortest Path Fi)
rst).

In the RIP, each network periodically (for example, every 30 seconds) multicasts routing information. Each router knows the distance (the number of hops) to the network from the routing information and performs routing based on the distance (the number of hops) to the network. In the OSPF, the link state of a network is exchanged between routers, network topology information (network connection relationship) is created, and a routing control table is created based on the topology information.

[0004]

However, the RIP
However, there is a problem that the number of hops is limited and cannot be handled when the network is large. In the OSPF, each node shares the link state of the network. However, the communication volume of control packets in the creation of the routing control table is large, and the traffic of information packets is suppressed. In addition, there is a problem that there is a lot of processing in the node and the load is large. In addition, the route control is limited due to the increase in the number of communication nodes, and is not suitable when there are many transfer destination nodes.

[0005] Further, in both the RIP and the OSPF, for example, when a new network is added as a radio base station is added in a mobile communication network, it is necessary to newly set a conventional routing control table. There is a problem that there is. The present invention has been made in view of the above problems, and provides a routing control method, a routing control table creating method, a routing control table, and a router, which can easily create a routing control table, can cope with an increase in a network, and have a learning function. The purpose is to provide.

[0006]

According to a first aspect of the present invention, there is provided a route control method for a router of a packet communication network, wherein the router controls a hop limit of a passed packet for each route and each source address. A sum of the hop limit numbers is obtained, and a route control is performed on a received packet having the source address as the destination address based on the sum of the hop limit numbers.

According to a second aspect of the present invention, there is provided a routing control table creating method for creating a routing control table for performing routing control, wherein a hop limit number of a passed packet is determined for each route and each source address. A sum is obtained, and priorities of transmission routes for received packets having the source address as a destination address are set in the order of the sum of the hop limit numbers.

According to a third aspect of the present invention, there is provided a routing control table created by the routing control table creating method according to the second aspect. According to a fourth aspect of the present invention, a router of a packet communication network that performs route control has a route control table for performing route control, and the route control table is obtained for each route and each source address. It is created based on the sum of the hop limit numbers of the packets that have passed, and the received packets are subjected to routing control based on the routing table.

[0009]

Next, embodiments of the present invention will be described with reference to the drawings. The packet mobile radio communication system will be described as an example. The packet mobile radio communication system has, for example, a configuration as shown in FIG. In FIG. 1, the mobile station (MS)
17, a base station network (BS network) 20 and a gateway station (GW) 21 for interfacing with other networks. The base station network 20 includes, for example, a base station (BS) 11
~ 16.

The base stations 11 to 16 are relay nodes for relaying a received packet to the next base stations 11 to 16 and function as a router of a packet communication network for performing route control based on the destination address of the packet. FIG.
1 shows the format of a P (Internet Protocol) datagram. This is a well-known IPv6 format, and a detailed description thereof will be omitted.

A packet is composed of a header part and a data part. Here, with respect to the header portion, the hop limit number, source address, and destination address related to the present invention will be briefly described. Hop limit number is I
It has the same meaning as the lifetime of Pv4 (Time To Live). Takes the expected value when sending the packet,
Each time it goes through a router, it decreases by one. When the value becomes 0, the packet is not transferred.

In the present invention, the initial value of the hop limit number is a fixed value. Since it has an 8-bit configuration,
Up to 256 values can be taken. The source address is composed of 128 bits and represents the source address of the packet. The source address is composed of a source network address and a source terminal (host) address.

The destination address is composed of 128 bits and represents the destination address of the packet. The destination address includes a destination network address and a destination terminal (host) address. An example of a router and a route will be described with reference to FIG. The router 10 is a router that configures a network, and controls a route of a received packet.
The router 10 receives a packet from a certain route and transfers the received packet to another route based on the routing control table stored in the storage unit 20.

In the illustrated router 10, routes are from R1 to R8.
(Routes 11 to 15), route 11 (R1) and route 1
4 (R4), the packet is transmitted from the router 10, and the router 10 transmits the packet to the route 16 (R6). As described above, the packet has a data part (30, 3
1, 32) and a header section (40, 41, 42).

The route control table stored in the storage means 20 describes the destination route corresponding to the destination address. The router 10 refers to the routing control table, determines a destination route corresponding to the destination address in the header of the received packet, and transfers the received packet. The routing control table of the present invention is created based on the routing status table. FIG.
Is a path status table of the present invention.

[0016] Packet header (40, 41, 42)
As described above, the lifetime of the address (for example, IP
v4) or the number of hops (hop limit number, IPv6) indicating the number of remaining passing routers (both are referred to as “hop limit number” in this specification). As described above, the hop limit number decreases by one each time a packet passes through a router. The hop limit number of a packet that has just been generated is large, and the hop limit number of a packet that has been generated and passed through many routers. Is small.

Therefore, the hop limit number of a packet from the transmission source network close to the node is large. The source of a packet with a large hop limit number has a high probability of being present on the incoming route. If a packet of the same transmission source network comes from the same route, there is a high possibility that the network is on that route. Therefore, if the hop limit number is integrated for each network and route of the transmission source, there is a high probability that the network of the transmission source exists in the route having a large integrated value.

From this, the route of a specific network can be estimated by integrating the hop limit number of the received packet. FIG. 4 is a table in which the hop limit number of passing packets is integrated for each route of the network address. For example, looking at the result of integrating the hop limit number of the packet with the network address A, the hop limit number is 50 from the route R1,
There is no hop limit number 121... From the route R3, not from the route R2. The same goes for other networks.

FIG. 5 is a routing control table obtained from the routing status table of FIG. According to FIG. 4, the hop limit number of each route of the network A is the largest at 121 for route R3, 98 for route R4, and 50 for route R4.
Followed by one. From this, it can be estimated that the network A has the highest probability of being in the direction of the route R3, the next is the route R4, and the next is the route R1.

Similarly, for other networks, the order of certainty of the route of the network can be estimated. The route of the received packet is determined based on the order of certainty of the route of the network. For example, a received packet addressed to network address A is most likely to be on route R3, so a received packet addressed to network address A is forwarded to route R3. Similarly, a received packet addressed to the network address B is transferred to the route R8.

In this manner, the router 10 controls the route of the received packet. The network address A
Even if the received packet is addressed to, if the route R3 has a failure, the packet is transferred to the route R4 having the next probability. According to the present embodiment, for each network address, for a distant network, it is not a definite route but can be determined only vaguely. However, for a nearby network, a route that is almost certain can be indicated.

Further, when determining a route, only the process of simply adding up the number of remaining hops is required, and a route control table can be easily created while performing a normal process.
Further, since the accumulation of the number of remaining hops is performed for each route and each network address, a learning function is provided, and the probability increases as time elapses. Also, when a new network is added, it is only necessary to add the network to the table, and there is no need to reset the existing table.

In the above description, an example of a mobile communication network has been described. However, the present invention is not limited to a mobile communication network but is applied to a general packet communication network.

[0024]

As described above, according to the present invention, it is possible to easily create a route control table and to cope with an increase in the number of networks.
A routing control method having a learning function, a routing control table creation method,
A routing table and a router can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining packet mobile radio communication.

FIG. 2 is a diagram illustrating a format of a packet.

FIG. 3 is a diagram for explaining a router and a route.

FIG. 4 is a diagram for explaining a route state table.

FIG. 5 is a diagram for explaining a route control table.

[Explanation of symbols]

 10 Router (communication node) 11-18 Route of router

Claims (4)

[Claims] 1. A route control method in a router of a packet communication network, wherein the router obtains a total sum of hop limit numbers of passed packets for each route and for each source address, and sets the source address as a destination address. A route control method based on the sum of the hop limit numbers. 2. A route control table creating method for creating a route control table for performing route control, wherein a sum of hop limit numbers of passed packets is obtained for each route and each source address; A priority of a transmission route with respect to a received packet having a destination address set in the order of the sum of the hop limit numbers. 3. A routing control table created by the routing control table creation method according to claim 2. 4. A router of a packet communication network for performing a route control, the router having a route control table for performing a route control, wherein the hop of the passed packet obtained for each route and each source address is referred to. A router that is created based on the total sum of the limit numbers and performs routing control on received packets based on the routing control table.