JPS62216449A - Routing system - Google Patents

Abstract

PURPOSE:To obtain a highly efficient routing system by making general terminals to know positions of other terminals unnecessary and making a network connecting device handle similarly communication destined to single terminal, multiple address communication and group communication by simple processing without being conscious of them. CONSTITUTION:Comparison discriminating circuits 1-4-i (i=1 or 2) compare destination address of received frame with the content of a routing memory 1-5, and when the destination address is not yet stored in the routing memory 1-5 or when a link other than link (i) is recorded in the attribute of the destination address, sends out transmission request to transmitter-receivers 1-2-i' connected to the recorded link, and the transmitter-receivers 1-2-1' send out received information frame in receiving buffers 1-3-i to the link i'. In other cases, the comparison discriminating circuits 1-4-i clear buffers 1-3-i. Thus, transmission is made to a recorded link other than received side irrespective of whether the link number of received side is recorded or not.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is composed of a plurality of communication media having broadcasting properties and a plurality of network connection devices that interconnect them. This paper relates to a routing method in a communication network that does not include.

[Conventional technology]

As a routing method in a communication network that is composed of multiple communication media with broadcasting properties and multiple network connection devices that connect them to each other, and does not include any logically closed circuits, look at the source address of the information frame. A method is being considered in which routing is performed using only the relative position information of each terminal to itself obtained by this method. In this method, each network connection device stores the source address of the received information frame as routing information for each link, and compares the destination address of the received information frame with the routing information corresponding to each link. If the destination address of the received information frame is not included in the routing information of any link, the received information frame is sent to all links other than the link where it was received, and if the destination address of the received information frame is not included in the routing information of the received link. If the destination address of the information frame is included, the received information frame is not sent to any link.

[Problem that the invention seeks to solve]

Although this method poses no problem when used for communication addressed to a single terminal or for so-called broadcast communication addressed to all terminals within a communication network, it may be inconvenient when used for group communication. Group communication is communication addressed to multiple terminals belonging to a specific group. Generally, group communication is performed by using a group address unique to that group as the destination address, but since the group address is not used as the source address, in the conventional method described above, it is not included in the routing information of the network connection device. Therefore, information frames for group communication will always be sent to all communication media. However, from the viewpoint of communication path usage efficiency, it is desirable that information frames for group communication should be sent only to communication media directly connected to terminals that belong to the group. Furthermore, there may be cases where the inflow of information frames from other groups has an adverse effect, such as when different upper-level protocols are used for each group, and in such cases, the above method cannot be used.

The purpose of the present invention is to provide communication to a single terminal in a communication network that is composed of a plurality of communication media having broadcasting properties and a plurality of network connection devices that interconnect them, and which logically does not include a closed circuit. It is an object of the present invention to provide a routing method that makes it possible to efficiently perform all broadcast communications and group communications addressed to all terminals.

[Structure of the invention]

The present invention relates to a routing method in a communication network that is composed of a plurality of communication media having broadcasting properties and a plurality of network connection devices that interconnect them, and that theoretically does not include a closed circuit. A specific group identifier unique to a group is assigned to a communication medium, and when performing intra-group communication within a specific group, the specific group identifier is used as a destination address, and the communication medium is directly connected to a communication medium that serves a specific group. The specific terminal transmits an information frame with the specific group identifier as the source address at a specific time, and each network connection device stores the source address of the received information frame as routing information for each link. In addition, the destination address of the received information frame is compared with the routing information corresponding to each link, and if the destination address of the received information frame is not included in the routing information of any link, the destination address of the received information frame is is sent to all links other than the link that received it, and if only the routing information of the received link includes the destination address of the received information frame, the received information frame is not sent to any link, If the destination address of the received information frame is included in the routing information of a link other than the received link, the received information frame is sent to all links corresponding to the routing information that includes that destination address. It is characterized by things.

[Effect] The principle of the present invention will be explained in detail below using the drawings.

FIG. 3 is an explanatory diagram showing an example of a communication network to which the present invention can be applied. In the figure, 2-1 to 2-3 are communication media having broadcasting properties, 2-4 to 2-5 are network connection devices, and 2-6 to 2-11 are
is a terminal. The communication network in Figure 3 physically does not include any closed circuits, but even in the case of a communication network that physically includes closed circuits, it is logically possible for communication to not include any closed circuits by not using some network connection devices. road can be constructed. In the figure, all network connection devices are each connected to two communication media. Here, the connection between the network connection device and the communication medium will be called a link, and for the sake of explanation, the upper link in the figure is link 1,
The lower link will be called link 2.

Each network connection device once receives all the information frames flowing on the communication medium to which it is directly connected, looks at the source address, and knows on which side of itself the source terminal is located. First, a case where only communication addressed to a single terminal is being performed will be explained. Still network connection device 2-
4. Both 2-5 are assumed to have no information at all. Assume that the terminal 2-6 transmits an information frame to the terminal 2-IO in this state. The network connection device 2-4 looks at the source address of the frame and establishes link 1 for the terminal 2-6 to itself.
Know that it is located next to you and record it.

Next, the destination address of the information frame is checked, but since the location information of the destination terminal 2-10 is not yet available, the received frame is transmitted as is to the link other than the one from which it was received, that is, the link 2 side. Network connection device 2-5 is network connection device 2-4
receives the information frame transmitted from link 2 from link 1, similarly records that the terminal 2-6 is located on the link l side with respect to itself, and then transmits it to the link 2 side. Destination terminal 2-10 can receive the information frame transmitted from link 2 by network connection device 2-5 via communication medium 2-3.

Next, assume that, for example, terminal 2-8 transmits an information frame to terminal 2-6. The information frame is sent to the network connection devices 2-4 and 2-5 via the communication medium 2-2, respectively. Received from link 1. Network connection device 2-4 is terminal 2-8
is on the link 2 side with respect to itself, and the network connection device 2-
5 each records that the terminals 2-8 are on the link I side with respect to itself. Next, look at the destination address, network connection device 2
-4 knows that the destination terminal 2-6 is located on the link 1 side, not on the link 2 side where it received the frame, so it transmits the received frame to the link 1 side, and the destination terminal 2-6 The information frame can be received. On the other hand, the network connection device 2-5 knows that the destination terminal 2-6 is located on the link 1 side that received the data, so it does not send it to the link 2 side, and therefore sends it to the unrelated communication medium 2-3. No unnecessary information frames are thrown away.

As explained above, if the location of the destination terminal is not known, it is transmitted to all links other than the receiving link, so it is guaranteed that the destination will be reached.

Furthermore, after all network connection devices know the location information of all terminals, unnecessary transmission to communication media is stopped, allowing efficient use of communication media.

As can be seen from the above explanation, each network connection device can learn the location information of a terminal connected to the communication medium to which it is directly connected, when that terminal sends an information frame even once; You can also know about a terminal at least once when that terminal transmits an information frame to a terminal connected to a communication medium to which it is directly connected. Furthermore, since the address of each terminal is unique within the communication network and the communication path does not logically include a closed path, the address of each terminal can be associated with two or more links of each network connection device. Never.

Next, broadcast communication addressed to all terminals will be explained.

When performing broadcast communications, a special identifier is usually used as the destination address, and this special identifier is never used as the source address. Therefore, for each network connection device, the frame is treated the same as an information frame addressed to a terminal whose location is unknown, and is eventually transmitted to all communication media to achieve broadcast communication.

A case where group communication is performed in ff1f& will be described. In Fig. 3, terminals connected to communication media 2-1 and 2-2, namely 2-6.2-7.2-8 and 2-9, form a group, and a unique number X is used as the group identifier. Assume that it is assigned. All terminals belonging to the group, in this case terminal 2-6.2-7.2
.about.8 and 2-9 each transmit an information frame having the group identifier Network connection device 2-4 receives and receives information frames with source address X sent by terminals 2-6 and 2-7 from link 1, and receives information frames sent from link 2 by terminals 2-8 and 2-9. The terminal receives an information frame whose source address is X, and therefore knows that there are terminals with address X on both sides of itself. Therefore, the network connection device 2-4 always transmits the information frame with destination address X received from one link to the other link. On the other hand, since network connection device 2-5 receives from link 1 the information frame with source address X sent from all terminals 2-6.2-7.2-8 and 2-9, the terminal with address Link 1 for
Knowing that it is located on the link 2 side, it does not transmit to the link 2 side. In this way, group communication information frames exchanged using group identifier do not have.

As explained above, according to this method, general terminals do not need to know the locations of other terminals, and network connection devices do not need to be aware of single terminal, broadcast communication, or group communication. An efficient routing method that can handle all of them in the same manner through simple processing can be obtained. In addition,
In the above explanation, we have described a case in which all terminals that submit to a group broadcast information frames with the group identifier as the source address at fixed time intervals, but it is not necessary for all terminals to do this, and each communication medium broadcasts one information frame. For example, the manager or one of the network connection devices directly connected to the communication medium may perform the communication on behalf of the manager.

〔Example〕

An embodiment of the routing method of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of a network connection device used in this embodiment, and FIG. 2 is a flowchart showing the operation of the network connection device of FIG. 1. In FIG. 1, 1-1-1.1-1-2 are links connected to media with different broadcast properties. I will call it. The operation will be explained below along the flowchart of FIG. The information frame received from link i (i=1.2) is sent to buffer 1 via transmitter/receiver 1-2-i.
-3-i (step ■).

The comparison/determination circuit 1-4-i reads the source address of the received frame and compares it with the contents of the routing memory 1-5 (
Step ■). In the routing memory 1-5, the source addresses of information frames received so far from link 1 or link 2 are recorded with the received link number as an attribute. Comparison/discrimination circuit 1-4-i is configured so that the source address of the received frame is already in routing memory 1-4.
5, check the link number and (
Step ■), if link i is not recorded as an attribute, write the link number i (Step ■), and if the source address is not yet recorded in the routing memory 1-5 (Step ■), send Write the original address and link number i as a pair (step ■). Next, the comparison/discrimination circuit 1-4-i compares the destination address of the received frame with the contents of the routing memory 1-5 (steps ■, ■), and if the destination address is not yet recorded in the routing memory 1-5 or the destination If a link other than link i is recorded in the address attribute, the transmitter/receiver 1-
2-i'(i' = 1 if i = 2, bi = 2
If 1=1), the transmitting/receiving device 1-2-i' issues a transmission request to link i' (step ■), and transmits the received information frame in the receiving buffer 1-3-4 to the link i' (step [phase]
). In other cases, the comparison/judgment circuit 1-4-i clears the buffer 1-3-i (step 2).

Among the above operations, the difference from the conventional method described above is step ①.In the conventional method, if the link number of the receiving side is recorded in the destination address attribute, it is cleared and it is not sent to any link. In this method, regardless of whether the link number of the receiving side is recorded or not, the message is sent to a recorded link other than the receiving side.

〔Effect of the invention〕

As explained above, according to the present invention, there is no need for general terminals to know the locations of other terminals, and network connection devices do not need to be aware of single terminal communication, broadcast communication, and group communication. An efficient routing method that can handle all of them in the same manner through simple processing can be obtained.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an example of a network connection device used in an embodiment of the present invention, FIG. 2 is a flowchart showing an example of the operation of the network connection device, and FIG. 3 is a detailed explanation of the present invention. FIG.

Claims (1)

[Claims] (1) In a routing system in a communication network that is composed of multiple communication media with broadcasting properties and multiple network connection devices that interconnect them, and theoretically does not include closed circuits, belongs to a specific group. A specific group identifier unique to a group is assigned to a communication medium, and when performing intra-group communication within a specific group, the specific group identifier is used as a destination address, and the communication medium belonging to the specific group is directly connected. The specific terminal transmits an information frame with the specific group identifier as the source address at a specific time, and each network connection device stores the source address of the received information frame as routing information for each link. In addition, the destination address of the received information frame is compared with the routing information corresponding to each link, and if the destination address of the received information frame is not included in the routing information of any link, the destination address of the received information frame is is sent to all links other than the link that received it, and if only the routing information of the received link includes the destination address of the received information frame, the received information frame is not sent to any link, If the destination address of the received information frame is included in the routing information of a link other than the received link, the received information frame is sent to all links corresponding to the routing information that includes that destination address. A routing method characterized by: