JPH08331090A - Path monitor system - Google Patents

Abstract

PURPOSE: To attain sure path monitor of each channel by a small circuit scale. CONSTITUTION: A frame phase of a low-order group signal of each channel is in matching by SDH signal output sections 3-1 to 3-n and a path pattern is inserted to an A1 byte of a tip of each frame by path pattern insert, sections 4-1 to 4-n. Succeedingly delay sections 5-1 to 5-n are used to delay a low-order group signal of each channel at a different delay time respectively to shift a frame phase of each low-order group signal, that is, a path pattern, a selector 7 selects sequentially a low-order group signal of each channel received by a channel changeover section 6 and gives the selected signal to a path pattern check section 8 in time division to detect and confirm a path pattern in time division.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is applicable to, for example, SDH (Synchr
The present invention relates to a path monitoring method for monitoring an in-device path in a transmission device compliant with onous Digital Hierarchy).

[0002]

2. Description of the Related Art In an SDH-compliant transmission device such as a network switching device, a path pattern check is performed to monitor a failure in the device. The pass pattern check inserts a specific pattern (pass pattern) at a predetermined position (for example, A1 byte located at the frame front end) of a transmission signal on the transmission side related to intra-device transmission, and the reception side detects and confirms this pass pattern. This is what monitors the normality. Note that, for example, in a network switching device conforming to SDH, signals of a plurality of channels (for example, 16 channels) are internally transmitted, and a path pattern is inserted into each of the plurality of signals to perform a path pattern check.

By the way, a signal transmitted in the apparatus is a set of a data signal, a clock signal and a frame signal, but the clock signal and the frame signal are generated in the apparatus and are synchronized with each other. There is. That is, the data signals of the respective channels have the same phase as shown in FIG. For this reason, the path pattern is inserted at the same time point in each channel, and a path pattern check circuit is required for each channel.

As shown in FIG. 4, there is also an apparatus that transmits the phase of each channel randomly, but even in this case, the path pattern of one channel may overlap with the path pattern of another channel in terms of time. , It is necessary to provide a path pattern check circuit corresponding to each channel.

[0005]

As described above, the prior art is as follows.
Since the frame phase conditions of the signals of multiple channels are synchronous or random, there is a risk that the path patterns of one channel will temporally overlap with the path patterns of another channel, and a circuit for checking the path pattern is required for the number of channels. There was a problem that it increased.

The present invention has been made in consideration of such circumstances, and an object of the present invention is to provide a path monitoring system capable of reliably performing path monitoring of each channel with a small circuit scale. To provide.

[0007]

In order to achieve the above object, the present invention provides, for example, an SDH signal output section, a path pattern inserting section and a delay section in a transmitting section, in which each of a plurality of signals is transmitted in a frame. A predetermined pattern is inserted at the same position, and the frame phase of each channel is shifted by a predetermined period and transmitted. Also, for example, in a receiving unit including a channel switching unit, a selector and a path pattern checking unit, each of the plurality of signals is The confirmation processing of the inserted pattern is performed in a time-sharing manner.

[0008]

By taking such a measure, the pattern inserted in each of the plurality of signals transmitted from the transmitter is inserted in the same position in the frame whose phases are shifted by a predetermined period. , Exist at different times. In the receiving unit, the confirmation process of each pattern that is temporally shifted in this way is time-divisionally performed.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a main configuration of a network switching device configured by applying the path monitoring system according to this embodiment. This network switching device includes an optical receiving unit 1, a separating unit 2 and an S
DH signal output sections 3-1 to 3-n, path pattern insertion section (In
s) 4-1 to 4-n, delay sections 5-1 to 5-n, channel switching section 6, selector 7, path pattern check section 8, low speed interface section (low speed IF section) 9-1 to 9-n and Optical transmitter 10
-1 to 10-n.

The optical receiver 1 receives a high-order group signal (for example, an STM-16 signal) that has arrived as an optical signal via the optical fiber F1, converts it into an electric signal, and gives it to the demultiplexer 2.
The demultiplexing unit 2 outputs the high-order group signal from the optical receiving unit 1 to n
Channel (for example, 16 channels) low-order group signals (for example, STM-1 signals) are separated, and SDH signal output units
Give to 3-1 to 3-n.

The SDH signal output sections 3-1 to 3-n respectively correspond to the respective channels, and the low-order group signals of the corresponding channels are used as the internal clock signal CLK and the frame signal FP.
Output in synchronization with. The path pattern insertion parts 4-1 to 4-n are
Corresponding to each channel, a predetermined path pattern is inserted into the first byte of each frame in the low-order group signal of the corresponding channel, that is, A1 byte. Delay section 5-1 to 5-n
Corresponds to each channel and delays the low-order group signal of the corresponding channel by a predetermined time.

The channel switching unit 6 arbitrarily outputs the low-order group signals of the respective channels provided from the delay units 5-1 to 5-n to the low-speed interface units 9-1 to 9-n according to the setting. give. The n-channel low-order group signals input to the channel switching unit 6 are input to the selector 7,
These signals are selected in a predetermined order and given to the path pattern check unit 8. The path pattern check unit 8 detects and confirms the path pattern from the signal given from the selector 7 and monitors the path.

The low-speed interface units 9-1 to 9-n respectively send the low-order group signals supplied from the channel switching unit 6 to the optical transmission units 10-1 to 10-n at the clock timing and frame timing of the transmission path system. Output. Optical transmitter 10-1 to 10-n
Are optical fibers F2-1 to F2-n using the low-order group signals provided from the low-speed interface units 9-1 to 9-n as optical signals.
Send to.

Next, the operation of the network switching device configured as described above will be described. First, a high-order group signal that has arrived as an optical signal via the optical fiber F1 is converted into an electric signal by the optical receiving unit 1, and then separated into n low-order group signals by the separating unit 2. The n low order group signals are output to the SDH signal output unit 3-
1 to 3-n, respectively, and are output in synchronization with the internal clock signal CLK and the frame signal FP.
Thus, the low-order group signals output from the SDH signal output units 3-1 to 3-n have the same frame phase as shown in FIG.

In the path pattern inserting sections 4-1 to 4-n, SDH
A predetermined pass pattern is inserted into the A1 byte located at the tip of each frame of the low-order group signals given from each of the signal output units 3-1 to 3-n. This allows the pass pattern insertion section
The low-order group signal output from each of 4-1 to 4-n has a path pattern indicated by PP inserted in place of the A1 byte as shown in FIG.

Then, the low-order group signals in which the path patterns are inserted in this way are respectively delayed by the delay units 5-1 to 5-n. Here, different delay times are set in the delay units 5-1 to 5-n. Specifically, assuming that one frame period is T, the delay time set in the delay unit 5-1 is 0, the delay time set in the delay unit 5-2 is T / n, and the delay unit is
The delay time set to 5-3 is 2T / n,
The delay time is set to be sequentially longer in steps of / n, and the delay time set in the delay unit 5-n is (n-1) T / n.
Thus, the delay unit 5-1 is the low-order group signal of channel No. 1, the delay unit 5-2 is the low-order group signal of channel No. 2, and the delay unit 5-n is the low-order group signal of channel No. n. As shown in FIG. 2, the low-order group signal output from each of the delay units 5-1 to 5-n corresponds to the channel of the low-order group signal of channel No. 1 as shown in FIG. No. 2 low-order group signal is channel N
The low-order group signal of channel No. 3 is delayed from the low-order group signal of o.2 by T / n.
The phase of each low-order group signal is shifted.

The low-order group signals of the respective channels output from the respective delay units 5-1 to 5-n are arbitrarily set by the channel switching unit 6 to the low speed interface units 9-1 to 9-n according to the setting. Given to. Then, each low-order group signal is output to the optical transmission units 10-1 to 10-n at the clock timing and frame timing of the transmission path system by the low-speed interface units 9-1 to 9-n, and is output as an optical signal to the optical fiber. It is sent to F2-1 to F2-n.

By the way, the low-order group signals output from the delay units 5-1 to 5-n and input to the channel switching unit 6 are also branched and input to the selector 7. Selector 7
Are the delay units 5-1, 5-2, ..., 5-n in this order, and each delay unit 5-1 to
The low-order group signal output by 5-n is selected over the period of T / n and given to the pass pattern check unit 8. That is, the selector 7 gives the path pattern inserted in each low-order group signal of each channel to the path pattern check unit 8 in a time division manner. Then, the path pattern check unit 8 performs time-divisional path monitoring for each low-order group signal of each channel by sequentially detecting the path pattern given by the selector 7 in a time-divisional manner and checking the normality.

As described above, according to the present embodiment, the n-channel low-order group signal has the frame phase of each low-order group signal so that the path patterns inserted in each low-order group signal do not overlap each other in time. Shift and transmit to the channel switching unit 6,
Since the detection and confirmation are performed by the single path pattern checker 8 in a time division manner, it is possible to surely detect and confirm the path pattern inserted in each low-order group signal without fail, and The circuit scale is reduced as compared with the conventional case in which a plurality of pattern check units must be provided.

The present invention is not limited to the above embodiment. For example, in the above embodiment, the SDH signal output section 3-
The path between 1 to 3-n and the channel switching unit 6 is monitored. The monitored section is, for example, the SDH signal output unit 3-1 to 3-n and the low speed interface unit 9-1 to. It may be arbitrary between 9-n.

Further, the application of the path monitoring method of the present invention is not limited to the SDH-compliant network switching device. In addition, various modifications can be made without departing from the scope of the present invention.

[0022]

According to the present invention, in the transmitting section, a predetermined pattern is inserted at the same position in a frame for each of a plurality of signals, and the frame phase of each channel is shifted by a predetermined period for transmission. In the receiving unit, since the confirmation processing of the pattern inserted in each of the plurality of signals is performed in a time-divisional manner, it is possible to realize reliable path monitoring of each channel with a small circuit scale. It becomes a method.

[Brief description of drawings]

FIG. 1 is a block diagram showing a main configuration of a network switching device configured by applying a path monitoring system according to an embodiment of the present invention.

FIG. 2 is a low-order group signal output from each of SDH signal output sections 3-1 to 3-n, path pattern inserting sections 4-1 to 4-n and delay sections 5-1 to 5-n in FIG. The figure which compares and shows.

FIG. 3 is a diagram showing an example of a state of a conventional in-device transmission signal, and a diagram showing a case where the frame phases of the respective channels match.

FIG. 4 is a diagram showing an example of a state of a conventional intra-device transmission signal, showing a case where the frame phase of each channel is random.

[Explanation of symbols]

 1 ... Optical receiving unit 2 ... Separation unit 3-1 to 3-n ... SDH signal output unit 4-1 to 4-n ... Path pattern insertion unit (Ins) 5-1 to 5-n ... Delay unit 6 ... Channel switching unit 7 ... Selector 8 ... Path pattern checker 9-1 to 9-n ... Low speed interface (low speed IF) 10-1 to 10-n ... Optical transmitter

Claims (1)

[Claims] 1. A path monitoring method for transmitting a plurality of signals framed in the same format between a transmission unit and a reception unit in a device, wherein the transmission unit applies to each of the plurality of signals. On the other hand, a predetermined pattern is inserted at the same position in the frame, the frame phase of each channel is shifted by a predetermined period and transmitted, and the receiving section confirms the pattern inserted in each of the plurality of signals. A path monitoring method characterized by performing processing in a time-sharing manner.