Ciena Corporation

Clark Scrandis

Michael B Peters-Rodbell

Srinivasa Hebbar

Rajan Kapur

Martha Dunbar

Balakrishnan Sridhar

Michael George Taylor

Jun Bao

James E DeGrange, Jr

A distributed method and system of controlling a communications network having a plurality of spans of interconnected network elements some of which include a network element processor distributes network topology information to respective span databases; stores original fault objects in the respective span databases; advertises fault objects to other network element processors in a local span when the original fault affects network elements other than a network element in which the fault occurred; advertises alarm objects to other network element processors that are respectively associated with a circuit affected by the original faults; stores the advertised fault and alarm objects in the respective span databases; and performs distributed processing of the advertised fault and alarm objects with the other network element processors and the respective span databases. Aggregation of other faults and alarms that may be occurring on the communications network due to other faults other than the received fault aids in determining causality of the fault. Causality may be determined by correlating other faults and alarms with the received fault. If not a root cause of another fault or alarm, the received fault is sympathetic to another fault or alarm. Sympathetic faults are suppressed while root cause faults are promoted to an alarm and reported to affected network elements. The number of alarms viewed by a network manager as well as the reporting of alarms and underlying faults are reduced by performing such distributed alarm correlation and fault reporting suppression.

Method and apparatus for aggregating alarms and faults of a communications network

A three stage optical amplifier is disclosed having a substantially flat gain profile. The amplifier includes a variable optical attenuator coupled between second and third stages of the amplifier and a dispersion compensating element. The attenuation of the optical attenuator is adjusted in accordance with the loss across dispersion compensating element and the optical power input to the amplifier to thereby obtain a substantially flattened gain profile. An offset value can also be used to refine the variable optical attenuator control and minimize nonflatness. The first and second stages are preferably pumped to provide high gain and a low noise figure and the third stage is preferably pumped to provide a high optical conversion efficiency. In an additional example, received optical powers associated with each of the channels in a WDM system are monitored and the attenuators within each amplifier in the system are controlled so that the received powers are substantially equal.

Three-stage optical amplifier having flat spectral gain

Method of controlling a network element to aggregate alarms and faults of a communications network

Method and system for determining and suppressing sympathetic faults of a communications network

A distributed method and system of controlling a communications network having spans of interconnected network elements that distribute network topology information to respective span databases; advertise fault objects to other network elements in a local span when the original fault affects network elements; advertise alarm objects to other network elements that are respectively associated with a circuit affected by the original fault; and perform distributed processing of the advertised fault and alarm objects with the other network elements and the respective span databases. Other faults and alarms that may exist on the network are aggregated. Causality may be determined by correlating other faults and alarms with the received fault. Sympathetic faults are suppressed while root cause faults are promoted to an alarm and reported to affected network elements. The number of alarms viewed by a network manager are reduced by performing such distributed alarm correlation and fault reporting suppression.

Communications network and method performing distributed processing of fault and alarm objects

Method and system for processing alarm objects in a communications network

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Columbia, MD, United States of America

Clark Scrandis