Alarm Filter Hold-Off Processor Squelch AIS Differentiation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In nested protection systems, the hold-off mechanism unnecessarily delays protection switching by categorizing squelch signals as All Ones Indication Signals (AIS), preventing the client layer protection controller from taking immediate corrective actions, leading to significant traffic outages due to the inability to differentiate between AIS generated by squelching and other faults.
Innovation Solution
A method and system that mark alarms of a pre-defined pattern, disable hold-off operations for marked alarms, and use an alarm filter and hold-off processor to differentiate AIS generated by squelching from other faults, allowing the client layer protection controller to switch traffic to a failure-free path without delay.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hold-off mechanism is applied to all alarms including AIS, then multiple protection switches and traffic oscillation are prevented, but protection switching response time increases significantly
Solution Approach 1:
The alarm input is segmented into two distinct paths: one for squelch signals and one for other defects. The squelch signal path bypasses the hold-off mechanism entirely, while the other defect path retains the hold-off mechanism. This segmentation resolves the contradiction by allowing immediate response to squelch events without triggering traffic oscillation in other scenarios.
Solution Approach 2:
A separate squelch signal input acts as an intermediary that directly communicates with the protection controller, bypassing the alarm filter and hold-off timer. This intermediary path enables fast protection switching response while the main alarm path continues to provide oscillation prevention through the hold-off mechanism.
2Reliability
If hold-off period is configured for server signal fail and degrade alarms, then unnecessary switching due to transient faults is avoided, but corrective action delay occurs for significant faults
Solution Approach 1:
The alarm handling is segmented into squelch-related inputs that bypass hold-off and other defect inputs that undergo hold-off processing. This allows the system to avoid unnecessary switching for transient faults while enabling immediate corrective action when squelch signals indicate significant issues requiring prompt attention.
3Device complexity
If generic alarm filtering is used without differentiation, then system complexity is reduced, but AIS due to squelching is incorrectly held-off
Solution Approach 1:
The alarm filtering system is segmented into distinct input paths: one dedicated to squelch signals that bypasses the hold-off timer, and another for other defects that undergo normal hold-off processing. This simple segmentation eliminates the problem of incorrect hold-off delays without requiring complex differentiation logic.
Solution Approach 2:
Different quality of processing is applied to different alarm types: squelch signals receive immediate processing without hold-off, while other alarms receive delayed processing with hold-off. This local quality differentiation resolves the contradiction by tailoring the response characteristics to the specific nature of each alarm type.
Data Source
AI summary
The various embodiments herein provide a method and system for providing protection switching at a client layer on squelching of clients by a server layer protection controller in a nested protection system. The method comprises of marking a plurality of alarms of a pre-defined pattern and disabling a hold-off period for the plurality of marked alarms on receiving a squelch operation indication. The system comprises of one or more hold-off timers pre-configured with a hold off period and an alarm filter and hold-off processor (AFHP) for disabling the hold-off timer to invalidate the hold-off period for the plurality of marked alarms, wherein the plurality of marked alarms is an AIS generated due to squelching.