Monitor system for multiplex equipment

• US 4,993,013 A
• Filed: 09/29/1989
• Issued: 02/12/1991
• Est. Priority Date: 10/16/1987
• Status: Expired due to Term

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Fujita, Hiroyuki, Shinada, Shigeo
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): HSU, ALPUS
• Application Number:
  US07/414,599
• Time in Patent Office: 501 Days
• Field of Search: 370/13, 370/15, 370/84, 370/112, 370/14, 371/24, 371/71
• US Class Current: 370/242
• CPC Class Codes: H04J 3/14 Monitoring arrangements for SDH/SONET rings H04J3/085

Abstract

A monitor system for a multiplex equipment, comprising a multiplexing unit for multiplexing low speed group input signals of plural channels into a high speed group output signal and a demultiplexing unit for demultiplexing a high speed group input signal into low speed group output signals of plural channels, wherein the high speed group output signal and the low speed group input signals on one hand and the high speed group input signal and the low speed group output signals on the other hand are monitored through comparison on the basis of the low speed group signal. When discrepancy is detected in the comparison between the high speed group output signal and the low speed group input signal in a certain channel of the low speed group signal in the course of monitoring the multiplex unit, the comparison between the high speed input signal and the low speed output signal is performed in a different channel of the low speed group signal for monitoring the demultiplex unit. The time taken for making decision of the presence of fault from the detection of discrepancy in the comparison can be reduced, whereby exchange of the equipment suffering from the fault can be accomplished rapidly in response to the fault information, decreasing the shutdown duration involved in restoration.

Claims

1. A method of monitoring a multiplex equipment which includes a multiplexing unit for multiplexing low speed group input signals of plural channels into a high speed group output signal and a demultiplexing unit for demultiplexing a high speed group input signal into low speed group output signals of plural channels, wherein said high speed group output signal and said low speed group input signals and said high speed group input signal and said low speed group output signals are monitored through comparison on the basis of the low speed group signal, comprising:

(a) a step of performing comparison of said high speed group output signal and said low speed group input signals in accordance with the order of the channel sequence of the low speed group signals and subsequently performing comparison of said high speed group input signal and said low speed group output signals in accordance with the order of the channel sequence of said low speed group signals, said step being repeated until discrepancy is detected from said comparison;

(b) a step in which, when discrepancy between said high speed group output signal and a low speed group input signal is first detected in a given one of the signal channels of said low speed group signals, step (a) is discontinued and comparison is then performed between the high speed group input signal and the low speed group output signal in another channel differing from said given one channel of the low speed group signals, said comparison being subsequently performed in said order of comparison; and

(c) a step in which, when discrepancy is first detected between the high speed group input signal and the low speed group output signal in a certain channel of the low speed group signals, step (a) is discontinued and comparison is then performed between the high speed group output signal and the low speed group input signal in another channel differing from said certain channel, said comparison being performed in accordance with said order of comparison.

2. A monitor system for a multiplex equipment, comprising a multiplexing unit for multiplexing low speed group input signals of plural channels into a high speed group output signal;

a demultiplexing unit for demultiplexing a high speed group input signal into low speed group output signals of plural channels;

means for monitoring said high speed group output signal and said low speed group input signals and for monitoring said high speed group input signal and said low speed group output signals through comparison on the basis of the low speed group signals in a predetermined sequence; and

control means, responsive to a discrepancy being detected in the comparison between the high speed group output signal and the low speed input signal in a certain channel of the low speed group signals in the course of monitoring the multiplexing unit, for immediately discontinuing said predetermined sequence and effecting a comparison between the high speed group input signal and the low speed group output signal in a different channel of the low speed group signal than that in which said discrepancy was detected for monitoring the demultiplexing unit.