JPH06105904B2 - Communication method between local networks - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a network communication system in which a plurality of local networks are connected, and in particular, a station (ST) connected to different local networks communicates with each other. In this case, the present invention relates to a method of ascertaining the address of the communication partner ST that is suitable.

[Background of the Invention]

In a network composed of multiple rings (multiple rings), the address of each ST is, for example, IEEE (The Institut
e of Electrical and Electronics Engineers) 802.5 T
It can be represented by a ring number and ST number as specified in the oken Ring Draft. Here, each ST must obtain the address of the other ST, that is, the ST number and ring number, before communicating.

Consider ST movement on multiple rings. Here, how to get each ST's destination ring number becomes a problem. This is because the address of the ST is changed every time it moves (reconnects) to a different ring.

As a method of setting the ring number of the communication partner ST, there is a method of previously setting the ring number of the communication partner ST as part of the initialization before communication. In this method, for example, there is a problem that the ST has to grasp the ring number of the moving destination and re-initialize it. Also, a method of always transmitting to all rings of a plurality of rings can be easily considered as a kind of broadcast communication. However, this method has a problem of causing a dramatic increase in communication traffic.

There is a method according to the following document as a communication method between a plurality of rings.

"An Architecture for Interconnecting Token Rings"
Kien-Bon K.Sy, Daniel Avery Pitt, By Contributions t
o IEEE 802.5 Feb.13, 1984. The method according to the above document is also a method that enables communication between STs that span different rings.

This method does not obtain the ring number of the communication partner ST,
It is for obtaining the route information to the communication partner ST. The route information is a series of relay device (devices connecting different rings) number information to the partner ST. For this reason, a unique relay device number must be assigned to each relay device. Further, in this method, a special route information storage area is provided in the communication frame. Furthermore, this method has a problem that each ST must know the ring number of its own ST. How to get this ring number is not fully described.

Even in a network in which multiple local networks (corresponding to rings in the above example) are connected, if the address used for communication is represented by the local network number and ST number,
The same applies to the above.

[Object of the Invention] An object of the present invention is to provide a communication method that enables an ST connected to a network composed of a plurality of local networks to grasp the address (particularly, the local network number) of a communication partner ST. It is in.

[Outline of Invention]

As long as they communicate within a network consisting of a single ring, no ring number is required for each ST address. However, in the case of communicating between different rings in a network consisting of multiple rings (hereinafter, multiple rings), the ring number assigned to facilitate the relay decision of the received frame at the connection point of each ring. Is good. In addition, in a plurality of rings, there is always a relay device for connecting the plurality of rings. By considering the above-mentioned two points regarding a plurality of rings, the basic concept of the present invention in which the allocation of ring numbers or the like is made a function dedicated to the relay device can be derived. That is, the relay device sets the ring number of the ring from which the communication frame is taken out to the Source Address (SA) of the frame. In addition, the relay device sets the ring number of the ring to which the communication frame is to be sent to the Destin
ation Address (DA).

The present invention replaces the ring generally with a local network. For example, it can be applied to a case where communication is performed between local networks having a bus structure.

Example of Invention

An embodiment of the present invention applied to a ring network will be described below.

FIG. 1 shows the overall structure of the network. In FIG. 1, 1 is a reference network, 2 is a local ring network (local ring), and # 2, # 7, and # 9 are ring numbers of the local ring. Hereinafter, the ring number is the number of each ring. 3 (A, B, K) is a relay device that connects a plurality of local rings, and 4 and 5 are STs. In particular, ST4 is ST number # 25 and ST5 is ST number # 21.

FIG. 2 shows the structure of a communication frame. In Fig. 2, SD is Start Delimiter, DA is Destination Address,
SA for Source Address, INFO for Information, ED for Ending
It is a Delimiter. DA and SA include ring number and ST number.

Figure 3 shows DA and SA when ST4 seeks the ring number of ST5.
Indicates the transition of information. If ST4 does not know the ring number of ST5, ST4 sends a communication frame to all the rings. When ST5 receives the frame, ST5 returns a response to notify the source ST of the frame of the ring number of its own ST. Below, the transition of DA, SA information in the above procedure, each ST,
Each relay device will be described. In FIG. 3, I indicates DA and SA at the time of ST4 transmission. II is the local ring # 7 including ST4 and is transmitted by the relay device 3 (A), and III (a) is the local ring # 7.
The relay devices 3 (B) and III (b) of No. 9 are DA and SA at the time of transmission of the relay device 3 (K) of the local ring # 2. IV indicates DA and SA at the time of ST5 reception.

In I.ST4, the DA ring number is addressed to all local rings (broadcasting or Broadcasting is shown as'B 'in the figure), and the ST number is the ST number of ST5, that is, # 21. The SA ring number is '0' and the ST number is # 25.

II. When the relay device 3 (A) receives a frame addressed to all local rings, it sets the ring number of the received local ring, ie, # 7, to the SA ring number of the frame. The frame is transmitted to another ring.

Upon receiving the frame, the relay device 3 (B) of III (a) sets the ring number of the local ring to be transmitted (relayed) here, that is, # 9, to the ring number of the DA of the frame.

III (b) The relay device 3 (K) sets # 2 as the ring number of the DA by the same process as the relay device 3 (B).

Since IV.ST5 is connected to the local ring # 2, the frame relayed by the relay device 3 (K) is received.

By the above procedure, ST5 can know the ring number of the local ring to which the own ST is connected and the ring number of the partner ST4. Therefore, toward ST4, the DA can send the response frame by specifying the individual address (ring number # 7, ST number # 25) and the SA by setting the individual address (ring number # 2, ST number # 21). On the other hand, ST4 can grasp the individual addresses of ST5 and its own ST by receiving the response frame.

FIG. 4 shows an operation flow in each relay device.

(A) shows the operation in the relay device (3 (A) in the above-mentioned embodiment) that received the frame from the local ring to the other local ring. The destination of the frame is all rings (B: Broadcas
Checking (100) whether or not it is ting), and if it is addressed to all rings, set the ring number of the local ring that received the frame to the SA ring number. (B) shows the operation in the relay device (3 (B), 3 (K) in the above-mentioned embodiment) when sending the received frame from the reference network to the local ring. The destination of the frame to be transmitted here is checked whether it is addressed to all rings (200). If it is addressed to all rings, the ring number of the destination local ring is set to the ring number of DA (201).

Regardless of the above procedure (operation flow), the relay device may set the ring number of the local ring in the frame each time the frame is relayed.

5 and 6 show application examples of the present invention. The difference from FIG. 1 is that a plurality of local rings of each relay device are connected. When the STs connected to different local rings connected to the same relay device communicate with each other, the SA and DA ring numbers are set in the relay device.

The above embodiment is an example in which the local network referred to in the present invention is a ring. The same is true whether the local network is a bath network or a star network.

In the above embodiment, the relay device stores the ring numbers in the SA and DA, but the following is also possible. That is, the relay device only stores the ring number of the ring from which the communication frame is extracted in the SA. The ring number is not stored in DA. In this case, each ST cannot grasp the ring number of the ring to which the ST connects, but can grasp the ring number of the communication partner ST.

〔The invention's effect〕

According to the present invention, each ST can obtain its address in a block-like manner (by exchanging communication frames), regardless of where the local network of the communication partner ST is connected. Therefore, there is an effect that the manual intervention becomes unnecessary and the load of the address generation and the like before the start of the steady communication can be reduced.

According to the present invention, each ST does not need to know the local network number to which it is connected. Therefore, there is an effect that the procedure for notifying each ST of the local network number is unnecessary.

As described above, there is an effect that each ST can be arbitrarily (without centrally managing) connecting to a network and conscious of the existence of a local network for movement.

[Brief description of drawings]

FIG. 1 shows the overall structure of the network. FIG. 2 shows the structure of a communication frame. FIG. 3 shows the update process of the address information (especially DA, SA) in the communication frame. FIG. 4 shows an operation flow in the relay device. 5 and 6 show an example of applying the present invention to a network structure other than that shown in FIG. Fig. 4 (101) …… SA ring number setting, (201) …… DA ring number setting. Fig. 3 Update of DA and SA ring number information.

Claims (1)

[Claims] 1. A communication method between local networks connected via a relay device, comprising: (a) a source device connected to a first local network uses an address unique to itself as a source address part. And transmitting a broadcast frame including a unique address and a broadcast address in a destination address part of a destination device connected to the second local network, and (b) the relay device connected to the first local network. , After adding an address unique to the first local network to the source address part of the broadcast frame received from the first local network,
Transmitting the broadcast frame to a relay device connected to the second network, (c) the relay device of the second local network, the destination address part of the broadcast frame transmitted from the first relay device. After replacing the broadcast address contained in the second local network with an address unique to the second local network, (d) the destination where the frame is received from the second local network, The device includes the first included in the received frame
Of the local network and the address unique to the source device are included in the destination address part, and the address unique to the second local network and the address unique to the own device included in the received frame A response frame included in an address part is transmitted to the second local network, and (e) each of the relay devices relays the response frame according to an address of the local network included in the destination address part. A method of communication between local networks.