Distributed Fault Identification in Telecommunication Networks

Telecommunications networks are often managed by a large number of management centers, each responsible for a logically autonomous part of the network. This could be a small subnetwork such as an Ethernet, a Token Ring or an FDDI ring, or a large subnetwork comprised of many smaller networks. In response to a single fault, in a telecommunications network, many network elements may raise alarms, which are typically reported only to the subarea management center that contains the network element raising the alarm. As a result, a particular management center has a partial view of the status of the network. Management Centers must therefore cooperate in order to correctly infer the real cause of the failure. The algorithms proposed in this paper, outline the way these management centers could collaborate in correlating alarms and identifying faults. Key Words: Distributed Fault Identification, Management Domain, Alarms. 1 First Bank of Boston, Boston MA 0216, USA. Work done while the aut..

Distributed fault localization in hierarchically routed networks

Probabilistic inference was shown effective in non-deterministic diagnosis of end-to-end service failures. To overcome the exponential complexity of the exact inference algorithms in fault propagation models represented by graphs with undirected loops, Pearl’s iterative algorithms for polytrees were used as an approximation schema. The approximation made it possible to diagnose end-to-end service failures in network topologies composed of tens of nodes. This paper proposes a distributed algorithm that increases the admissible network size by an order of magnitude. The algorithm divides the computational effort and system knowledge among multiple, hierarchically organized managers. The cooperation among managers is illustrated with examples, and the results of a preliminary performance study are presented. 1