Method and system for fault isolation within a network element in an optical network
First Claim
1. A method for fault isolation within a network element (NE) in an optical network, the method comprising:
- constructing a directed acyclic graph (DAG) based on the NE topology, the DAG having edges connecting vertices, each vertex representing a physical port direction in the NE;
identifying root cause alarms according to steps of;
finding starting vertices in the DAG;
pruning the edges of the DAG;
pruning the starting vertices of the DAG;
performing a topological sort of the vertices in the DAG; and
performing a topological walk of the DAG; and
masking remaining correlated alarms within the NE.
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Abstract
A method and system for fault isolation within a network element in an optical network is described. A single fault in the system can give rise to multiple alarms detected at multiple points. Finding the root cause alarm corresponding to the fault that has triggered these alarms is important for fault isolation and is the focus of attention for this invention. The network element is modeled by a directed acyclic graph that captures the interactions among various components in the network element. Using a graph-based technique the invention analyzes the various topological faults raised and their locations for identifying root cause alarms and masking all correlated alarms.
15 Citations
23 Claims
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1. A method for fault isolation within a network element (NE) in an optical network, the method comprising:
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constructing a directed acyclic graph (DAG) based on the NE topology, the DAG having edges connecting vertices, each vertex representing a physical port direction in the NE; identifying root cause alarms according to steps of; finding starting vertices in the DAG; pruning the edges of the DAG; pruning the starting vertices of the DAG; performing a topological sort of the vertices in the DAG; and performing a topological walk of the DAG; and masking remaining correlated alarms within the NE. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A system for fault isolation within a network element (NE) in an optical network, the system comprising:
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means for constructing a directed acyclic graph (DAG) based on the NE topology, the DAG having edges connecting vertices, each vertex representing a physical port direction in the NE; means for identifying root cause alarms comprising; means for finding starting vertices in the DAG; means for pruning the edges of the DAG; means for pruning the starting vertices of the DAG; means for performing a topological sort of the vertices in the DAG; and means for performing a topological walk of the DAG; means for masking of all remaining correlated alarms within the NE; and a display unit for displaying said root cause alarms. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A method of fault isolation within a network element (NE) in an optical network, comprising the steps of:
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(a) marking optical channel paths in the network element with respective unique signatures in a form of low frequency dither tone modulation; (b) detecting faults in the NE by analyzing the unique signatures at the physical ports of the network element; and (c) identifying root cause alarms among a plurality of alarms caused by said detected faults in the NE by analyzing said faults in the NE using directed acyclic graph (DAG) wherein said physical ports represent vertices in the DAG. - View Dependent Claims (21)
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22. A system for fault isolation within a network element (NE) in an optical network, comprising:
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(a) an optical signature generator for generating unique signatures and marking optical channel paths in the network element with respective unique signatures in a form of a low frequency dither tone modulation; (b) an optical signal detector for detecting faults in the NE by analyzing the unique signatures at the physical ports of the NE; and (c) a processing module comprising a computer program instructions stored in a computer readable memory for identifying root cause alarms among a plurality of alarms caused by said detected faults in the NE by analyzing said faults in the NE using a Directed Acyclic Graph (DAG), wherein said physical ports represent vertices of the DAG. - View Dependent Claims (23)
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Specification