JP2616381B2 - SDH reception path status judgment method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an SDH (Synchronous
The present invention relates to a method of determining a state of a higher-order path in a receiving unit of a (noous Digital Hierarchy) transmission method.

[0002]

2. Description of the Related Art FIG. 2 shows an example of a conventional reception path state determination circuit. This circuit is an STM (Synchronous)
This is a circuit for determining the reception path state of the Transfer Mode-4 signal. There is one AU pointer for every 51.84 Mb / s of the basic bit rate, which indicates the head of the transmitted path in the SDH signal, and also indicates the path state (normal, AIS) and the path size (connection state). Represent.
The receiving side determines these path states and path sizes based on the value of the received AU pointer. When a pointer that should not be transmitted is received, it is determined that the path is abnormal.

In the case of this circuit example (STM-4), since the bit rate is 622.08 Mb / s, the AU pointer is 1
There are two. If the paths are connected, the path status is determined by looking at all the connected AU pointers. In this circuit example, since the received signal is STM-4,
There are three types of path sizes: VC-3 (single), VC-4 (three linked), and VC-4-4c (12 linked). The reception path state determination circuit includes 12 circuits (101 to 112) for determining the state of VC-3, four circuits (201 to 204) for determining the state of VC-4,
One circuit for determining the state of VC-4-4C (3
01) Required.

[0004] Further, the state determination of the VC-4 processes three AU pointers simultaneously, and the state determination of the VC-4-4C is A
Since it is necessary to process 12 U pointers simultaneously,
C-4 path state determination circuits 201 to 204 and VC-4
The -4C path state determination circuit 301 is a large-scale circuit.

In a single reception path state determination circuit, a plurality of circuits may determine different path states. For example, from the definition of the AU pointer by CCITT, VC-
When four signals are received, VC-4 reception can be determined by looking at all three corresponding AU pointers. However, VC-3 reception can be determined by the head AU pointer of the corresponding path alone.
Further, the second and third AU pointers alone cannot determine whether the reception pointer is in a linked display or in an abnormal state. Therefore, the priority processing circuit 401 performs final path size and state determination based on the determination result of each reception path state determination circuit, and outputs the determination result from the output terminal 402.

[0006]

In the conventional circuit, it is necessary to prepare a reception path state determination circuit for all the path sizes that may be transmitted. As the number of combinations of receivable path sizes increases, there is a problem that the circuit scale is dramatically increased.

An object of the present invention is to provide an SDH reception path state determination method which solves such a problem.

[0008]

[MEANS FOR SOLVING THE PROBLEMS] To achieve the above object
In addition, the present invention provides a method for receiving a currently received packet for each AU pointer.
Display contents of the interface (normal pointer display, abnormal pointer table
Display, AIS pointer display, and path connection pointer table
) And outputs it to the path size judgment circuit.
AU pointer determination circuit and multiple received AU pointer determination
Determines and determines the path size of the received signal from the circuit determination result
Notifying the path status determination circuit of the
Abnormal pointer table of each AU pointer from the size determination result
Indication criterion, and the criterion is determined by a plurality of reception AU points.
A path size determination circuit for notifying the
Each AU pointer determination result from the reception AU pointer determination circuit
Result (normal pointer display, abnormal pointer display, AIS Poi
Display and path connection pointer display) and path size
Combining with the path size judgment result from the judgment circuit
And the state of each path in the received STM-n (n ≧ 1) signal.
And a path state judgment circuit for judging the state.

[0009]

FIG. 1 shows an embodiment of an SDH reception path state judging method according to the present invention. This SDH reception path state determination method is as follows.
2 is a circuit for determining the reception path state of the STM-4 signal, similarly to the circuit of FIG.
, Path size determination circuit 21 and path state determination circuit 22
It is composed of

The received AU pointer determination circuits 1 to 12 determine the display contents (normal pointer display, AIS pointer display, path connection pointer display) of the currently received pointer for each AU pointer.

The path size determination circuit 21 determines the path size of the received signal from the result of the determination, notifies the path state determination circuit 22 of the determined path size, and displays the abnormal pointer of each AU pointer based on the path size determination result. The criterion is determined, and the criterion is notified to the reception AU pointer determination circuits 1 to 12.

The reception AU pointer determination circuits 1 to 12 further determine an abnormal pointer display for each AU pointer according to the abnormal pointer display determination criterion from the path size determination circuit 21.

The path state determination circuit 22 determines each AU pointer determination result (normal pointer display, AIS pointer display, abnormal pointer display) from each of the AU pointer determination circuits 1 to 12 and the path size determination from the path size determination circuit 21. The state of each path in the received STM-n signal is determined by combining the result.

Next, the operation of this embodiment will be described.

The received AU pointer determination circuits 1 to 12 independently determine which of the received AU pointer represents a normal pointer display, an abnormal pointer display, an AIS pointer display, or a link display. The determination results of the normal pointer display, the AIS pointer display, and the path connection pointer display are input to the path size determination circuit 21, where the reception path size is determined. From this result, an abnormal pointer display determination criterion is notified to each reception AU pointer. If the path size is changed, the abnormal pointer display determination criterion is changed.

In the reception AU pointer determination circuits 1 to 12,
An abnormal pointer display of the reception pointer is determined based on this determination criterion.

The path state determination circuit 22 determines whether the reception path is in a normal state, an AIS state, or an abnormal state based on the pointer display determination results in the respective reception AU pointer determination circuits 1 to 12. The result is output from the output terminal 23.

[0018]

As described above, according to the present invention, when determining the path status, first, the display contents of the reception pointer are independently determined for each AU pointer, and the path size is determined based on the result. . An abnormal pointer determination criterion is determined for each AU pointer according to the path size, and abnormal pointer display is determined independently by each AU pointer. By performing all the processing for determining the path state independently for each AU pointer in this manner, it is possible to reduce the circuit scale.

[Brief description of the drawings]

FIG. 1 is a block diagram of one embodiment of the present invention.

FIG. 2 is a block diagram of a conventional example.

[Explanation of symbols]

1 to 12 reception AU pointer determination circuit 21 path size determination circuit 22 path state determination circuit 23 output terminal 101, 102, 103, 104, 105, 106, 1
07, 108, 109, 110, 111, 112 VC
-3 path state determination circuit 201, 202, 203 VC-4 path state determination circuit 301 VC-4-4c path state determination circuit 401 priority processing circuit 402 output terminal

Claims (1)

(57) [Claims] A plurality of AU pointers each of which determines display contents (normal pointer display, abnormal pointer display, AIS pointer display, and path connection pointer display) of a pointer currently received for each AU pointer and outputs it to a path size determination circuit. And the path size of the received signal is determined from the determination results of the plurality of reception AU pointer determination circuits, and the determined path size is notified to the path state determination circuit, and the abnormality of each AU pointer is determined based on the path size determination result. A path size determination circuit that determines a pointer display determination criterion and notifies the plurality of reception AU pointer determination circuits of the determination criterion, and AU pointer determination results (normal pointer display, abnormal pointer display, AIS pointer display and path connection pointer display) and the path sensor from the path size determination circuit. SDH receive path state determination method characterized by comprising the status of each path in the receiving STM-n (n ≧ 1) signal from the determined path state judging circuit by combining's determination result.