Topology-based fault analysis in telecommunications networks
AssigneeMCI Communications Corporation
InventorRoger D. Harris
Life of this patent
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Abstract
A method and apparatus for detecting traffic-affecting failures in a telecommunications network; by inferring the most probable location of each such failure, given multiple alarm indicators along a network circuit; correlating circuit alarms to trunk failures, or inferring trunk failures from circuit alarms; inferring the location of major network outages by topologically correlating multiple trunk failures; and filtering alarm reporting to the Fault Management System users such that only the most significant derived or inferred conditions are automatically displayed.
Claims6
A fault detection method for a telephone network having multiplexer and transmission equipments, comprising the steps:
- sensing faults occurring in particular components of the network and generating fault alarm data therefrom;
- propagating the alarm data downstream through the network for collection at an end point;
- positioning a database at the end point:
- loading entries in the database that characterize the topology of the network and contain entries relating to routing of circuits and trunks through the network, and more particularly define
- (a) which trunk or ordered sequence of trunks contain a given circuit;
- (b) which circuits are contained within a given trunk;
- and
- (c) the topological route through the network for any given circuit or trunk;
- subjecting the database to the collected alarm data;
- correlating the collected alarm data with the database for producing information regarding
- (d) significant fault alarm events distinguished from sympathetic events, to determine the topographic point of failure;
- (e) inference of an outage on a trunk, where no fault alarms are directly received from trunk equipment, but where correlated alarms on multiple circuits contained within the same trunk are detected;
- and
- (f) confirmation of an outage, where direct alarms have been reported on a trunk;
- wherein the step of correlating the collected alarm data with the database further includes the steps of
- resetting a previously set circuit alarm counter to zero for all upstream trunks extracted from the topology database;
- determining whether a detected circuit alarm is the first to be counted on an upstream trunk;
- in the event it is the first to be counted, storing an alarm time stamp and a set of all upstream trunks for the circuit for which an alarm is detected;
- in the event it is not the first to be counted, determining whether the alarm has been received within a pre-selected time window relative to a previous count of a corresponding circuit alarm counter;
- in the event that it is within the window, incrementing the circuit alarm counter and determining a common path set;
- in the event that it is not within the window, determining whether the fault has been explicitly reported or inferred for the affected trunk;
- in the event that it has been explicitly reported, ignoring the alarm as spurious;
- in the event that it has not been explicitly reported, resetting the circuit alarm counter to 1 and storing as new alarm data
- (a) a reset circuit alarm time and;
- (b) a list of upstream trunks.
Dependencies are inferred from the claim text.