JPH0828696B2 - Performance monitoring method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital communication network system each having a high-speed transmission line for transmitting a plurality of low-bit transmission-rate channel signals as time-division multiplexed signals having a high-bit transmission rate, In particular, it relates to a scheme for monitoring the performance of one of the channel signals in the multiplexed signal for such a digital communication network scheme.

[0002]

2. Description of the Related Art In a digital communication network system, a plurality of low bit rate channel signals, for example, DS1 signals each having a bit rate of 1.544 MHz (that is, 1.544 Mb / s) have a high bit rate. Multiplexed signal, eg bit rate 4
4.736 MHz (that is, 44.736 Mb / s)
Are multiplexed to form a DS3 signal. The DS3 signal is transmitted via the high speed transmission line. In digital communication networks, monitoring the performance of one or more DS1 channel signals is performed.

In the conventional performance monitoring system, a demultiplexer and a multiplexer are provided in a high speed transmission line. The DS3 signal is demultiplexed and separated into a plurality of DS1 channel signals by a demultiplexer, and the separated DS1 channel signals are respectively sent to a plurality of low speed transmission lines. The DS1 channel signal is again multiplexed into the DS3 signal by the multiplexer and sent to the high speed transmission line. The line monitoring device is connected to a specific one of the low speed transmission lines, that is, branched from the specific one. Therefore, the line monitoring device can receive a specific one of the DS1 channel signals on a specific low-speed transmission line, and can monitor the performance of the specific DS1 channel signal.

[0004]

In conventional monitoring schemes, even to monitor only one of the DS1 signals,
Demultiplexers, multiplexers, multiple low speed transmission lines, and line monitoring devices are needed. This increases equipment costs. Further, in order to change the DS1 channel signal to be monitored from a specific one to another, it is necessary to change the low-speed transmission line connected to the line monitoring device from a specific line to another. This operation is inconvenient.

It is an object of the present invention to provide a method for monitoring the performance of one of the DS1 signals in a high bit rate DS3 signal , which is easy to change the channel signal to be monitored at a low equipment cost. is there.

[0006]

According to the present invention, a DS1
Signal performance monitoring method is D
Obtained to be used in a digital communication network system having a node connected to a transmission path for transmitting an S3 signal , each of the DS3 signals has a bit transmission rate of 44.736 MHz. , DS1 signals with a bit rate of 1.544 MHz . The DS1 signal is an information
Information data section for carrying data and cyclic redundancy check code
Cyclic redundancy check code part to carry the performance
Report messages and bit-oriented messages
Extended superframe with functional data link section for carrying
Has (ESF). The performance report message is
It is a message that has been scheduled and
Contains Nita information. Bit-oriented messages
It is a message that is not scheduled, and alerts and status information
Including information. The performance monitoring method of the present invention
According, the node is connected to a transmission line, and the cross-connect between the DS3 signal in DS1 signal level <br/> Le has a Chi Yan'neru output port, DS1 within a particular one of the DS3 signal
Select a particular one of the signals, the cross connect means for sending the particular DS1 signal to the channel output ports are connected to the channel output port, handles specific DS1 signals, the information data section in a particular DS1 signal And cyclic redundancy check
Detects error in specific DS1 signal based on code part
And a monitoring means for outputting the functional data link unit in the specific DS1 signal .

[0007]

Embodiments of the present invention will now be described with reference to the drawings. Referring to FIG. 1, a digital communication network system generally includes a plurality of user devices, one of which is one.
1 is shown. ) Has. The user equipment is connected to a multiplexer / demultiplexer (MUX / DMUX) 12 via a low speed transmission line, that is, a DS1 line 13. The multiplexer / demultiplexer 12 is connected to the office station 14 via a high speed transmission line, that is, a DS3 line 15. The office station 14 is also the other DS3 line 1
6 is connected. The other DS3 line is also connected to another multiplexer / demultiplexer and another user equipment. Therefore, the office station is a node in the digital communication network system.

Channel signals of a plurality of bit rates from the user equipment, that is, the DS1 signals are multiplexed by the multiplexer / demultiplexer 12, and the DS3 line 1
5 to the office station 14 as a DS3 signal. On the other hand, the DS3 signal transmitted from the office station 14 via the DS3 line 15 is demultiplexed into a plurality of DS1 signals by the multiplexer / demultiplexer 12, and these DS1 signals are respectively transmitted via the DS1 line 13 to the user equipment. To 11 counterparts.

The office station 14 performs switching that enables communication between two user devices via the office station 14.

The performance of the DS1 signal is monitored at the user equipment 11 and the office station 14 to ensure communication between the user equipment in the digital communication network system.

The user device 11 receives the DS1 that arrives there.
It has a customer service unit (CSU) 17 that detects signal errors and holds them as performance data.
Performance data is carried by the DS1 signal to send it to the office station 14.

Referring to FIG. 2, the office station 14 is provided with a demultiplexer 18 to isolate a particular one of the DS1 signals to be monitored in the received DS3 signal. The demultiplexer 18 demultiplexes the received DS3 signal and separates it into a plurality of DS1 signals on a plurality of lines 19, respectively. Track monitoring device (LM
U) 20 is connected to a specific one of the lines 19, i.e. branched from the specific one, and receives a specific DS1 signal. The line monitoring device 20 not only detects the performance data sent from the user device, but also detects an error in the DS1 signal. Errors and performance data are retained and used for network maintenance and management.

The separated DS1 signal is again multiplexed by the multiplexer 21 to reproduce the DS3 signal.

The conventional performance monitoring system has the problems described in the preamble of the description.

Referring to FIG. 3, according to the present invention, the office station comprises a cross-connect system 31 for cross-connecting at the DS1 level. The office station also has a track monitoring device 32 connected to it.
It has.

The cross-connect system 31 includes a plurality of DS3 interfaces (DS3) connected to the DS3 line.
INT) 33 and a plurality of DS1 interfaces (DS1
INT) 34 and cross-connect network 35
And a controller 36 for controlling the cross-connect network 35, and an input terminal 37 for sending an arbitrary command to the controller 36.

The cross-connect system 31 is under the control of the controller 36, at the DS1 level, between the DS3 interfaces 33, between the DS1 interfaces 34, and D.
Cross-connect is performed between the S1 and DS3 interfaces 33 and 34. Further, according to the command from the input terminal 37, the DS coming to the DS3 interface
A particular one of the DS1 signals in the three signals is broadcast to one or more DS1 interfaces 34.

Such a broadband cross-connect system is known per se in the past as a broadband cross-connect system, which is, for example, 1989.
Bellcor (Bellcor)
e) disclosed in TR-TSY-000233.
A broadband cross connect system is incorporated here.

The line monitoring device 32 is connected to one particular output port 38 of the DS1 interface 34.

Specific one of the DS1 signals in the incoming DS3 signal
One is designated by the input terminal 37 and a specific DS1 signal is broadcast to a specific DS1 interface. So,
The line monitoring device 32 receives a specific DS1 signal and can monitor it.

Other DS1 signals are easily monitored by input terminal 37 by changing the designation from one particular to the other.

Referring to FIG. 4, an example of a cross-connect system is shown in detail. Each of the DS3 and DS1 interfaces includes 33a and 34a and 33b and 34
As indicated by b, the transmission side and the reception side are separated. The cross connect network 35 includes a serial / parallel converter (S
/ P) 41, a time switch (TSW) 42, and a parallel / serial converter (P / S) 43.

The DS3 signal arriving at each of the transmitting side DS3 interfaces 33a is supplied to the serial / parallel converter 41 and converted into a parallel signal, which is supplied to the time switch 42.

The plurality of DS1 signals arriving at the transmitting DS1 interface 34a are multiplexed to form a DS3 type multiplexed signal, which is serial / parallel converter 4.
1 is supplied. The multiplexed signal is then also converted into a parallel signal and fed to the time switch 42. The time switch 42, under the control of the controller 36, processes these parallel signals and performs cross-connects at the DS1 level. The processed and cross-connected signal is supplied to the parallel / serial converter 43 and converted into a cross-connected serial signal. The cross-connected serial signals are sent to the receiving DS3 and DS1 interfaces 33b and 34b, respectively. The reception side DS3 interface 33b sends out the cross-connected serial signal to its output port, respectively. At the same time, receiver D
The S1 interface 34b demultiplexes the received cross-connected DS3 signals into a plurality of DS1 signals, which are sent to its output port.

Such a cross-connect system is disclosed in US Pat. No. 4,935,921, assigned to NEC Corporation by Ishizaki et al.

The specific one of the DS1 signals in the incoming DSD3 signal is broadcast to the receiving side DS1 interface 34b as the specific one of the DS1 signals according to the command from the input terminal 37.

The line monitoring device 32 is the receiving side DS1.
It is connected to a particular one of the output ports of interface 34b. Therefore, the track monitoring device has a specific D
The S1 signal can be received and monitored.

In this case, the specific DS1 signal is also maintained at the specific one of the cross-connected DS3 signals sent to the receiving DS3 interface 33b. Therefore, the performance of a particular DS1 signal is monitored without affecting the DS1 signal in the DS3 signal to be transmitted and cross-connected.

For improved performance monitoring, extended superframe (ESF) is known in the prior art as the DS1 signal frame format, as disclosed in the Bellcore TA-TSY-000147 line monitoring equipment specifications. Has been. The ESF includes a Cyclic Redundancy Check (CRC) code part and a Functional Data Link (FDL) part.

The transmitting device uses C based on the transmission information data.
The RC code is calculated, and the calculated CRC code is transmitted as the transmission CRC code together with the transmission information data. The receiving device receives the transmission CRC code and the transmission information data, and
It is received as an RC code and reception information data. The receiving device recalculates the CRC code based on the received information data, and compares the recalculated CRC code with the received CRC code. It can be seen that a bit error has occurred in the transmission line when both CRC codes do not match each other.

Returning to FIG. 1, the CSU 17 calculates the CRC code as the transmission CRC code and introduces the transmission CRC code into the DS1 signal in the ESF frame format. The CSU 17 also detects an error in the DS1 signal coming from the office station 14 and outputs a byte-oriented performance report message (PRM) and a bit-oriented bit-oriented message (BOM). These PRM and BOM are supplied to the office station 14 via a functional data link called LAPD (D channel link access procedure). The PRM is a scheduled message and contains performance monitor information. BOM is an unscheduled message,
Includes alarm and status information.

Referring to FIG. 5, an example of a line monitoring device is shown using the ESF format as the DS1 signal.

The line monitoring device is a DS1 synchronizer 5
One. The DS1 synchronizer 51 recalculates the CRC value from the received information data in the received DS1 signal and compares the recalculated CRC value with the received CRC code. When both CRCs do not match each other, the DS1 synchronizer 51 outputs an error pulse. Further, the DS1 synchronizer 51 extracts the functional data link signal from the received DS1 signal.

The error counter 52 is connected to the DS1 synchronizer 51 and counts error pulses from the DS1 synchronizer 51. The contents of the error counter 52 are registers (not shown)
Is held.

The BOM detector 53 and the PRM detector 54 are D
It is connected to the S1 synchronizer 51, and the functional data link signal extracted by the DS1 synchronizer 51 is supplied. BOM
The detector 53 detects the BOM and the PRM detector 54 detects the PR
Detect M. The detected BOM and PRM are held in another register (not shown).

The contents of these registers are used for network maintenance and management.

[0037]

As described above, according to the present invention, the cross connect system is provided with the DS to be branched by the operator's operation.
By providing a signal branching interface that can set one signal, it is possible to set a predetermined monitoring point without intervening extra demultiplexing in the network, and change the monitoring target. It has an effect that it can be easily done.

[Brief description of drawings]

FIG. 1 is a schematic block diagram showing a digital communication network system.

FIG. 2 is a schematic block diagram illustrating a conventional scheme for monitoring DS1 performance.

FIG. 3 is a schematic block diagram showing a monitoring method in an office station in a digital communication network method according to an embodiment of the present invention.

FIG. 4 is a schematic block diagram showing an example of a cross-connect system.

FIG. 5 is a schematic block diagram showing an example of a line monitoring device.

[Explanation of symbols]

11 user equipment 12 multiplexer / demultiplexer (MUX / D
MUX 13 DS1 line 14 Office station (node) 15 DS3 line 16 DS1 line 17 Customer service unit (CSU) 18 Demultiplexer (DMUX) 19 Line 20 Line monitoring unit (LMU) 21 Multiplexer (MUX) 31 Cross-connect system 32 line Monitoring device (LMU) 33 DS3 interface 34 DS1 interface 35 Cross-connect network 36 Controller 37 Input terminal 38 Output port 41 Serial / parallel converter (S / P) 42 Time switch (TSW) 43 Parallel / serial converter (P / S) ) 51 DS1 synchronizer 52 error counter 53 BOM detector 54 PRM detector

Claims (2)

[Claims] 1. A Pafomasu monitoring system DS1 signals used in the digital communication network system having a connected to the transmission line for transmitting a DS3 signal, respectively (15) node (14), the DS3 signal each has a bit rate of 44.736 MHz, a plurality of DS1 signals bit rate of 1.544 MHz, the DS1 signal, information data for carrying information data
Section and a cyclic redundancy check code for carrying a cyclic redundancy check code.
And the performance report message and bit
The function data link part that carries the
Having an extended superframe (ESF) with the performance report message scheduled
Message that includes performance monitor information.
The bit-oriented message is scheduled
Messages that do not contain alerts and status information.
Seen, the node (14) is connected to said transmission line (15), the cross-connection between the DS3 signal at the DS1 signal level, Chi Yan'neru output has a port (38), 1 specific of the DS3 signal Selecting a particular one of the DS1 signals of the two
A cross-connect means (31 ) for sending a DS1 signal to the channel output port (38) and a signal connected to the channel output port (38) for processing the specific DS1 signal and processing the information in the specific DS1 signal.
Based on the report data part and the cyclic redundancy check code part,
Error in the constant DS1 signal is detected, and the specific D
Monitoring means for outputting the functional data link part in the S1 signal
(32) A performance monitoring method having 2. The specific DS1 signal has transmission information data, a transmission cyclic redundancy check code, and a transmission function data link signal, and the monitoring means (32) is responsive to the specific DS1 signal. , The specific DS1 signal
The transmission information data in the signal, the transmission cyclic redundancy check code,
And the transmission function data link signal, respectively, as the reception information data, the reception cyclic redundancy check code, and the reception function data link signal, and calculates the cyclic redundancy check code from the reception information data as a recalculated redundancy check code, First means for comparing the recalculated redundancy check code with the received cyclic redundancy check code, and outputting an error signal when the recalculated redundancy check code and the received cyclic redundancy check code do not match each other. (51) , a counter means (52) connected to the first means (51) for counting the error signal, and a counter means (52) connected to the first means (51) for responding to the reception function data link signal. to the a bit second means for detecting the oriented message (53), coupled to said first means (51), the receiving function In response to Tarinku signal, claim and a third means for detecting (54) the performance report message
Performance monitoring method described in 1 .