JPS58116835A - Node extension system - Google Patents

Abstract

PURPOSE:To prevent the occurrence of a data error during node extension by inserting an extension transmission line into a main transmission line after obtaining the synchronism of data on the main transmission line with that on the extension transmission line. CONSTITUTION:An existent node 100 is equipped with a T branch circuit 10, synchronizing elastic buffer 11, and transmission line 12 and is connected to a transmission line. When an extension node 20 is added to it nearly, a signal branched from the circuit 10 is transmitted to the buffer 11 via the extension node 200. Through an extension transmission line 2, the node 200 is connected to the transmission line 1 on branch basis. Then, the nose 100 performs frame synchronization between data in the buffer 11 and data on the transmission line 1 and then changes a switch 12 from the transmission line side 1 over to the buffer side 1 once completing the synchronization. This system eliminates the occurrence of a data error due to a step out in loop-back operation, performing the extremely smooth extension.

Description

[Detailed Description of the Invention] (1) Technical Field of the Invention The present invention relates to a method for adding nodes in an information processing network, and in particular, switching transmission paths and adding nodes without disturbing the flow of data on the transmission path. Regarding the method.

(2) Technical background: - If distributed processing and office automation become more widespread, the loop network method may spread rapidly. A combination dispersed in a relatively narrow ground, -
Local network systems for interconnecting terminal devices have begun to be commercialized mainly in the United States.

The WJI diagram is a model of a loop network, T (08T
is a host combination, -ta, CCPFi line controller, CN
is the center node, Sv is the monitoring control node for the entire loop, TN is the terminal node, and each terminal node has a facsimile (FAX) and a printer (printer).
), a word processor (WP), a graphic terminal, and other various terminals are connected.

In such a network, each terminal can not only use a host computer but also perform data communication between users via respective nodes.

Networks like Matato are suitable for data communications within offices and between two main factories in buildings and local factories, and are likely to become popular rapidly.

(3) Conventional technology and problems As a method of adding new nodes to an existing loop-type network, the conventional method is as shown in Figures 2 (a), (b), and (e).
This is done according to the steps shown below. FIG. 2 shows only the loop portion.

In Fig. 2 (a), (b), and (c), CN and TN
has already been explained. TNX is the node to be expanded, A
.

The nine loops are named the A loop and the inner loop t-B loop in the BFi loop name. In other words, it is a 21f system loop, and normally the A loop is used, but it can now be switched to the B loop in the event of a failure. ing.

When trying to add a new node TNX to the above loop network, as shown in Figure 2 (b) (TNI,
A new closed loop is constructed by connecting A loop and B loop' within the node of TNi+1. This better method is called loopback. Next, when the new node TNX has been inserted, the loop paralysis is released, and the expansion is completed as shown in FIG. 2(c).

However, according to this loop pattern, A loop, B
Even if the loops are connected to form one loop, frame synchronization will occur and data errors will occur. A loop, B
The loops are originally separate loops and are synchronized within each loop, but the A and B loops are not synchronized.

Therefore, even with the function of the supervisory control node Sv, a loss of synchronization will occur.

(4) Purpose of the Invention The object of the present invention is to provide a node addition method that prevents the occurrence of data errors when adding nodes in the conventional method and does not affect network operation.

(5) Structure and embodiments of the invention The basic configuration of the present invention is shown in FIG.

The node 100 includes a T branch circuit 10, a synchronization elastic buffer 11, a transmission path switch 12, and a processing section 13.
and is connected to the transmission line 1. When a new node 200 is added to this, the signal branched from the T branch circuit 10 is transmitted to the synchronization elastic buffer 11 via the node 200. The node 200 is branch-connected to the transmission Wlr1 by the additional transmission line 2.

Next, node ]00 performs frame synchronization between the data in the synchronization elastic buffer 11 and the data on the transmission path.
Switch from the transmission line 1@ to the synchronization elastic buffer ll side.

Although the expansion operation is completed above, the details of the present invention will be further explained using FIG. 4.

FIG. 4(a) shows the state of frames on the transmission path before adding nodes. F is the flag y at the beginning of the data frame), f
l'l is the data of the nth frame.

Arrows indicate the flow of data; data flows into 21 from the processing unit 13, data flows from 22 to other nodes,
23 represents the flow of data from the branch circuit to the expansion node.
4 shows the flow of data from the expansion node.

FIG. 4B shows a case where there is no synchronization elastic buffer (hereinafter abbreviated as buffer) 11 and the frame positions do not match.

FIG. 4(C) shows a case where synchronization is achieved by the action of the buffer 711. Since the lengths of transmission line 1 and transmission line 20 are different, the phases of the data on each transmission line do not match at point P in FIG. 4(C), but the phases can be matched by adjusting the length of buffer 11. I can do it. When synchronization is achieved, the transmission line switch 12 is connected to the t buffer 11 side, as shown in FIG. 4(d), and the expansion is completed.

Synchronization (position of the flag bit) monitoring, switching control of the transmission path switch 12, etc. can all be performed by the processing 1113. In this operation, for example, when the flag bits of transmission line 1 and buffer 11 are detected simultaneously, an AND circuit is operated, and the output of the AND circuit is used to operate the transmission line switch 12.
This can be easily achieved by switching.

(6) As described in detail, this method has the great effect of not causing data errors due to out-of-synchronization during loopback, and allowing for extremely smooth expansion. In a high-speed, multiplex communication network, even a slight disturbance in the line can have a big impact, so the effects of the present invention are extremely significant.

[Brief explanation of drawings]

Figure 1 is a diagram showing the basic configuration of a conventional loop network, Figure 2 is a diagram explaining conventional node addition, Figure 3 is a diagram explaining the node addition method of the present invention, and Figure 4 is a diagram showing the existing transmission line and There is a diagram 't% explaining synchronization with an additional node. In FIG. 3, 100 is an existing node, 200 is an expansion node, 10 is a T-branch circuit, and 11 is a synchronization elasty, kuba, and fa. 12 is a transmission path switch, and 13 is a processing section. Usui 1 Prisoner mushroom 2 drawing 3ri! J

Claims (1)

[Claims] A branch circuit that branches data between the main transmission path and an expansion transmission path including an expansion node, at a node connected to the main transmission path and a device that functions by being connected to the main transmission path, and an output of the expansion transmission path. An elastic buffer for adjusting the synchronization of data and data via the main transmission line, and a transmission line switch for switching between the main transmission line and the additional transmission line are provided, and the data on the image transmission line is A node expansion method in which, when synchronization is achieved, the transmission path switch is activated and the expansion transmission path including the expansion node is inserted into the main transmission path.