JPS62216542A - Routing system - Google Patents

Abstract

PURPOSE:To improve the utilizing efficiency by providing a sole manager to each communication medium to constitute a channel of logical direction not including a closed path directed to each manager from all communication media corresponding to each manger and to eliminate the need for the information relating to the location of a designation terminal thereby forming the shortest path routing. CONSTITUTION:Network connection equipments 1-5-1-9 have a terminal table belonging to communication media 1-1-1-4 assigned to each manager sent from the managers 1-11-1-13 in addition to a routing table. Each network connection device indexes the routing table corresponding to a link receiving a reception information frame and seeks a manager which is in charge of reception. If the manager is not listed in the routing table, the received information frame is renounced. When the manager is listed, the received information frame is transmitted from a corresponding transmission link. Thus, no special information and operation is not required for the terminal and an efficient routing system is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a routing system in a communication network in which a plurality of communication media having broadcast properties are connected by a plurality of network connection devices.

[Conventional technology]

Many routing methods have been considered in the past for communication networks in which a plurality of communication media having broadcasting properties are connected by a plurality of network connection devices, but they can be broadly divided into two groups.

One group is a method in which the source terminal knows the communication route to the destination terminal in advance and transmits information about the network connection devices on the communication route by putting it into an information frame from the beginning. This method requires each terminal to hold route information to all destination terminals, and is not suitable for, for example, a local area network where the configuration changes frequently.

The other group does not require each terminal to maintain any routing information, but instead aims to make it appear as if all terminals are connected via the same communication medium. This method places less burden on each terminal and is suitable for systems where the configuration is easy to change. An example of such a method is a method in which all information frames received by each network connection device are sent to all links other than the link from which they were received, regardless of the destination. However, in this method, the communication path is closed. In this case, duplicate reception occurs, which places a heavy processing burden on each terminal. A possible method to avoid duplicate reception in the above method is to construct a tree-structured logical communication path that does not include a closed path on a communication path that physically has a closed path, and then perform the same procedure as the above method. It will be done. This method will be explained using FIG. 2.

In FIGS. 2(a) and 2(b), 2-1 to 2-4 are communication media that perform broadcasting, and 2-5 to 2-9 are network connection devices. FIG. 2(a) shows a communication network that has a physically closed circuit as a whole. FIG. 2(b) shows a logical communication path that does not include a cycle and is configured on the communication network of FIG. 2(a).

In other words, the logical communication path of FIG. 2(b) is prevented from forming a closed circuit by not using the network connection devices 2=8 and 2-9 of FIG. 2(a).

[Problems to be Solved by the Invention] However, in such a system, for example, an information frame sent from a terminal connected to communication medium 2-3 to a terminal connected to communication medium 2-4 is not physically connected to the network. Despite the existence of a communication path that can be sent directly via the connection device 2-9, the communication medium 2-6 is transmitted via the network connection devices 2-6, 2-5 and 2-7.
1 and 2-2, and this is not preferable since it is wasteful in terms of communication medium usage efficiency and also causes a conflict between specific communication media. In this example, communication between the terminals on the communication medium 2-3 and the terminals on the communication medium 2-4 is preferably performed via the network connection device 2-9, and in communication between all terminals, each A routing method that uses the shortest path is desirable.

An object of the present invention is to provide a communication network consisting of a plurality of broadcasting communication media and a plurality of network connection devices, in which each terminal does not require any information regarding the location of a destination terminal, and moreover, enables shortest route routing. The objective is to provide a routing method for

[Structure of the invention]

The present invention provides a routing method for a communication system in which a plurality of communication media having broadcasting properties are connected by a plurality of network connection devices, in which a unique manager is provided for each communication medium, and a manager is assigned to all communication media for each manager. A logical directional communication path that does not include a closed circuit is configured toward each manager, and each manager notifies all network connection devices of the addresses of terminals directly connected to the communication medium for which it is responsible. The method is characterized in that the destination address of the received information frame is checked, and the route of the received information frame is determined in accordance with the logical directional communication path corresponding to the manager in charge of the destination address.

[Effect]

The principle of the present invention will be explained in detail below. Hereinafter, the connection between the sequential connection device and each communication medium will be called a link, and for the sake of explanation, the upper link of each sequential connection device will be called link 1 and the lower link will be called link 2 in each figure. . Furthermore, here, the term "the worst route" is used to mean the minimum number of network connection devices, that is, the minimum number of hops, from the sending terminal to the destination terminal.

According to the present invention, a special station called a unique manager is provided for each communication medium, and a logical directional communication path that does not include a closed path from all communication media to each manager can be configured for each manager. is necessary. Basically, to configure a logical communication path that does not include a closed circuit, information frames flowing on the communication medium must be received from the network connection device connected to the communication medium for each communication medium. The network connection devices responsible for transmitting data to other communication media must be selected one by one. Such a network connection device will be referred to as a connection device responsible for each communication medium. In order to configure the shortest communication path to each manager, select the network connection device with the smallest number of hops to the manager from among the multiple network connection devices connected to each communication medium as the communication medium's manager. All you have to do is choose the corresponding responsible connection device.

For example, the following procedure may be used to select the connection device responsible for each communication medium corresponding to each manager. Each manager is
A route determination frame with its own address written therein is transmitted using a specific group address determined between all network connection devices as the destination. In the frame for determining the route, there is a place to write the number 71 for the sender manager.
The source manager writes 0 there. The network connection device that receives this routing frame reads the number of hops written in the frame, and if the number of hops is equal to the number of routing frames previously received from the manager on the received link. It was written 71
Only when the received frame is smaller than the received link number, the received frame is recorded together with the received link number, and the value of the pop number in the frame is incremented by one and transmitted to all links other than the received link.

In this way, the number of hops written in the strategy determination frame increases by one each time it passes through one network connection device, but the number of hops written in the strategy determination frame increases by one, but if A network connection device that receives a frame with a damaged hop count discards the received frame. As a result of the above operations, after a certain period of time has elapsed, each network connection device determines the number of hops to each manager from the recorded route determination frame. The number of hops to each manager is determined by adding 1 to the smallest number of hops written in the received route determination frame from the manager. The communication medium to which the link that received the route determination frame with the hop count smaller than the own hop count is connected has a network connection device that is closer to the manager than itself, or the manager is directly connected. Since the communication medium is connected, it cannot be the responsible connecting device for that communication medium.

A link connected to such a communication medium will be referred to as a manager-side link. If a communication medium connected to a link that only received a route determination frame with a hop count greater than your own hop count knows that you are the closest, it will be assigned the responsibility of that communication medium. Become. If a link receives a route determination frame with the same number of hops as its own, there is another network connection device with the same number of hops on the connected communication medium. In this case, a conflict resolution rule is established to select one network connection device as the responsible connection device. As a rule for conflict resolution, for example, a unique address may be used for each network connection device, and the one with the smallest address may be selected as the responsible connection device.

In this manner, a unique connection device responsible for each communication medium is selected for each manager. Each network connection device knows the manager side link and the link on the communication medium side that is the responsible connection device for each manager, and the manager side link is known as the sending side and the link on the communication medium side that is the responsible device as the receiving side. By doing this, a logical directional communication path that does not include a cycle with the shortest number of hops toward each manager is constructed.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 3 shows a communication network in which a manager is provided for each communication medium of the communication network shown in FIG. 2(a). In Figure 3,
1-1 to 1-4 are communication media, 1-5 to l-9 are network connection devices, 1-1O to 1-13 are managers, and [.--. FIG. 1 shows a logically directional communication path that does not include a shortest path to each manager and that is configured by applying the above-described method to this communication network.

Figure 1(a) is manager 1-10, Figure 1(b) is manager 1-11, and Figure 1(C) is manager 1.
-12, FIG. 1(d) is a logical communication path toward the manager 1-13. Table 1 shows the contents of the routing tables held by each network connection device in FIG. 1 for routing.

Table 1 In addition to the routing table shown in Table 1, each network connection device maintains a table of terminals belonging to the communication medium assigned to each manager, which is sent from each manager. Each network connection device once receives all the information frames flowing on the communication medium to which it is connected, looks up the above table from the destination address of this received information frame, and learns the manager in charge of the destination terminal. Next, it looks up the routing table corresponding to the link that received this received information frame and searches for the manager in charge. If the responsible manager is not listed in the routing table, the received information frame is discarded.

If the manager in charge is listed, the information frame received from the corresponding sending link is sent.

[Effects of the Invention] As explained above, according to the present invention, an efficient routing system that does not require any special information or operation at the terminal can be obtained.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a logical communication path in an embodiment of the present invention, FIG. 2 is an explanatory diagram for explaining the conventional method, and FIG. 3 is a diagram showing a communication network in which a manager is provided for each communication medium. It is. 1-1 to 1-4 and 2-1 to 2-4...Communication media 1-5 to 1-9 and 2-5 to 2-9...Network connection device

Claims (1)

[Claims] (1) In a routing method in a communication system in which multiple communication media with broadcast capability are connected by multiple network connection devices, a unique manager is provided for each communication medium, and each manager is assigned a A logical directional communication path that does not include a closed path toward the manager is configured, and each manager notifies all network connection devices of the address of the terminal directly connected to the communication medium for which he/she is responsible. A routing method characterized in that the destination address of the received information frame is checked, and the route of the received information frame is determined according to a logically directed communication path corresponding to the manager in charge of the destination address.