JPH01282944A - Line loopback system - Google Patents

Abstract

PURPOSE:To eliminate the need for the management of an address of a loopback point by writing a relative address of a loopback point number till a desired loopback point to an address area of a transmission frame sent from a transmitter. CONSTITUTION:A relative address, e.g., 3(011) of a loopback point number till a desired loopback point is written into an address area 10 of a transmission frame sent from a transmitter 1 and a code such as 1 executing loopback is written and sent to a code area 11. On the other hand, a subtraction section 5 is provided to transmitters 1, 2, 3, the subtraction section 5 of each loopback point receiving a transmission frame decrements number of the relative addresses one by one and sends the result to the succeeding loopback point. A loopback execution section 6 at the loopback point where the relative address is 0 executes the loopback.

Description

[Detailed Description of the Invention] [Summary] In a communication network having a plurality of transmission devices having loopback execution units at the loopback points on a transmission path, loopback is executed from the transmission device on the transmission path at a desired loopback point. With regard to the line loopback method, the purpose is to provide a line loopback method that does not require management of loopback point addresses, and the address field of the transmission frame sent from the transmission device contains relative addresses of the number of loopback points of the desired loopback point. and write a code to perform wrapping in the code area and send it.
A subtraction unit is provided at the return point of each transmission device, and the subtraction unit of each return point that receives the transmission frame subtracts the number of relative addresses by 1 and transmits it to the next return point. The loopback execution unit is configured to execute loopback.

[Industrial application field]

In a communication network such as a public network, a private line network, or a LAN, which has a plurality of transmission devices each having a loopback execution unit at a loopback point on a transmission path, the present invention is applicable to a communication network such as a public network, a private line network, a LAN, etc. This invention relates to an improvement in a line loopback method for executing loopback at a desired loopback point in cases such as when performing line loopback.

[Conventional technology]

A conventional example will be explained below using figures.

Figure 4 is an explanatory diagram of the conventional line loopback method, (A)
are block diagrams of a communication network, and (B) and (C) are diagrams showing transmission frames to be transmitted.

As a communication network such as a public network, private line network, or LAN, there are multiple transmission devices 1', 2 on a transmission path as shown in Figure 4.
For example, communication is performed between the data terminals 7 and 9.

In this case, the following method has conventionally been used to loop back the line in order to perform a cut test via the transmission device 1' in response to an instruction from the data terminal 7.

In the first method, each transmission device has an absolute address of
2 is provided, and in the transmission frame sent from the transmission device 1, as shown in (B), 1.0 indicating execution or cancellation of loopback corresponds to the absolute address of each loopback point. Areas LP■, LP■, where the bits of are written
LP■.

Set up LP■.

Then, for example, if you want to execute loopback at the absolute address ■, write 1 in the LP ■ area of the transmission frame shown in (B) and send it, then at the absolute address ■,
Detects this, executes the loopback in the loopback execution section,
When canceling, 0 was written and transmitted in the LP area of the transmission frame.

However, in this method, when the number of loopback points increases, the data area becomes narrower, the amount of data that can be transmitted decreases, and the number of loopback points is also limited due to the frame structure.

In order to prevent this, as a second method, each transmission device 2'',
3" is given an absolute address ■■■■, but the transmission frame transmitted from the transmission device 1° has an address area 10 (as shown in (C)), and this area contains the address area 10 for the return point. An absolute address such as ■ is written and transmitted in the code area 11 with bits of 1 and 0 indicating execution or cancellation of loopback.

Then, at the looping point of the absolute address (2), this address and bit are detected, and if the bit is 1, the looping execution section executes the looping, and if the bit is 0, the looping is canceled.

In this case, the address area 10 can also be used as a data area when the loopback is not executed or cancelled.

[Problem to be solved by the invention]

However, in the conventional method, each time a new transmission device is added due to a change in the communication network, etc.
There is a problem in that address management becomes complicated because absolute addresses must be given to return points of the original transmission device and the new transmission device so that the absolute addresses are easy to understand and in order.

An object of the present invention is to provide a line return method that does not require management of addresses of return points.

[Means to solve the problem]

FIG. 1 is a diagram of the principle of the present invention, in which (A) is a block diagram of a communication network and transmission equipment, and (B) is a transmission frame.

As shown in FIG. 1(A), a transmission device 1 having loopback execution units 6 at a plurality of loopback points 2.3. When performing loopback at a desired loopback point from the transmission device 1 on the transmission path using a communication network on the transmission path, the following procedure is performed.

The address field 10 of the transmission frame shown in (B) transmitted from the transmission device 1 contains the relative address of the number of return points of the desired return point salt, for example 3 (011).
A code for performing loopback, for example 1, is written in the code area 11 and transmitted to each transmission device 1, 2, 3 . A subtraction unit 5 is provided at the return point, and the subtraction unit 5 at each return point that receives the transmission frame subtracts the number of relative addresses by 1 and transmits it to the next return point,
At the return point that is O, the return execution unit 6 executes the return.

[For production]

According to the present invention, when executing loopback, the relative address of the number of loopback points of the loopback point salt at which loopback is executed from the own transmission device, for example 3 (011), is written in the address area 10 of the transmission frame, and the code is When a code 1 for executing loopback is written and transmitted in the area 11, at each loopback point where the transmission frame is received, the subtractor 5 subtracts 1 one by one, and at the loopback point where the value is 0, the loopback execution section 6 Since the wrap is executed at the wrap point, there is no need to give an absolute address to the wrap point.

When canceling, it is sufficient to write 0 to the code area 11 and do the same as above.

The transmission frame in this case has a similar structure to that of the second conventional method, but even if a new transmission device is added due to changes in the communication network, it is still necessary to give an absolute address to the return point. There is no need to manage addresses.

〔Example〕

An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 2 is a schematic diagram of the line loopback method according to the embodiment of the present invention, (A) is a block diagram of the communication network, (B) is a transmission frame diagram, and FIG. 3 is a loopback point of the embodiment of the present invention. FIG.

FIG. 2(A) shows a communication network in which data terminals 8, 7, and 9 are used to communicate through each transmission device between the data terminals. This shows a case where loopback is executed at the loopback points of each transmission device 2, 3° 2'', 3'' according to the instruction.

In this case, the return point is 1 (001) in order from the return point closer to the transmission device 1 to the return point farther from the transmission device 1.

2 (010) 3 (011), 4 (100)
. . . When the relative address is recognized and loopback is executed at the third loopback point, for example, "011" is entered in the address insertion section 10 of the transmission frame shown in (B) according to the instruction from the data terminal. is written, and 1 is written in the code area 11 and transmitted.

Then, at the first turning point, 1 is added in the subtraction section.
Therefore, the relative address of address area 1o is 01
At the second turning point, the relative address becomes "001", and at the third turning point, the relative address becomes 000''.

Since the relative address has become "000", loopback is executed at this loopback point.

When canceling, write O in the code area 11 and do the same thing as above.

Next, the return execution instruction and the operation of the return point will be explained in detail with reference to FIG.

To instruct execution or cancellation of loopback, for example, the data terminal 7 sends to the loopback instruction unit 22 the relative address of the number of loopback points of the loopback point salt to be executed, such as "011", and the code 1 for loopback execution.
Or, when the release code 0 is specified, the loopback instruction section 22 sends these contents to the loopback instruction bit/address insertion section 23, and inserts a relative address into the address area 10 of the transmission frame shown in FIG. 2(B). , a return execution or cancellation code is inserted into the code area 11, respectively, and transmitted to the next return point.

Upon receiving the transmission frame created in this way as shown in FIG.
011" and the bit of the code area 11 are extracted and sent to the loopback control unit 21. If this bit is 1, it is recognized that loopback is executed. Also, an address such as "011" is sent to the subtraction unit 5, and 1
Reduce.

Even if 1 is subtracted, the result is 2, which is “010”, so the loopback control unit 21 does not instruct execution of loopback, but sets the loopback instruction bit.
The address insertion unit 23 inserts "010" into the address area 10 and 1 into the code area 11 of the original transmission frame, and then transmits the frame.

At the third turning point, the value subtracted by 1 in the subtraction unit 5 becomes 0, so the turning control unit 2 indicates that it has become 0.
Let 1 know.

Then, since the loopback control unit 21 recognizes the loopback execution based on the 1 bit of the received loopback execution,
The loopback execution unit 6 is instructed to execute loopback, and is caused to execute loopback.

To cancel, write the relative address in the address area 10 as above, write 0 in the code area, and send it to the loop control unit 2 at the third loop point.
1 recognizes this and instructs the loopback execution unit 6 to cancel the loopback.

Note that the address area 10 of the transmission frame in FIG. 2(B) can also be used as a data area when cancellation of loopback is not executed. Furthermore, if an address area is provided exclusively, the code area 11 can be omitted and if the bits of the address area 10 are all 1, it can be canceled.

Also, while the loopback is being executed, transmission frames in which 1 is written in the code area may continue to be sent, and when the loopback stops, the transmission frame may be canceled.

In addition, the number of protection stages may be set so that when the transmission frame for performing and canceling the return is repeated three times in a row, the execution and cancellation of the return is performed.

Furthermore, the present invention can of course be applied even if the transmission line is a loop transmission line.

〔Effect of the invention〕

As explained in detail above, according to the present invention, a line can be looped back without giving a special address to the loopback point of the transmission device of the communication network, so even if there is a change in the communication network, there is no need to specifically assign an address to the loopback point. This has the effect of eliminating the need for address management.

[Brief explanation of the drawing]

Fig. 1 is a diagram of the principle of the present invention, Fig. 2 is a schematic diagram of a line loopback method according to an embodiment of the present invention, Fig. 3 is a block diagram of loopback points according to an embodiment of the present invention, and Fig. 4 is a diagram of a conventional example. FIG. 2 is an explanatory diagram of a line loopback method. In the figure: 1.2, 3.1"12'+3'+4 pins; 2". 3'' is a transmission device, 5 is a subtraction unit, 6 is a loopback execution unit, 7 to 9 are data terminals, 10 is an address area, 11 is a code area, 20 is a loopback instruction bit/address extraction unit, 21 is a loopback control unit, Reference numeral 22 indicates a return instruction section, and 23 indicates a return instruction focus/address insertion section.

Claims (1)

[Claims] In a communication network having a plurality of transmission devices (1, 2, 3,) having loopback execution units (6) at loopback points on a transmission path, a transmission device (1) on the transmission path. When executing loopback at a desired loopback point from the transmission device (1), write the relative address of the number of loopback points up to the desired loopback point in the address field (10) of the transmission frame transmitted from the transmission device (1), and write the relative address of the number of loopback points up to the desired loopback point, and region(
11), a code for performing loopback is written and transmitted, and a subtraction unit (5) is provided at the loopback point of each transmission device (1, 2, 3,), and a subtraction unit (5) is provided at each loopback point that receives the transmission frame. In (5), the number of relative addresses is reduced by 1 and transmitted to the next return point, and at the return point that becomes 0, the return execution unit (6) executes the return. method.