A Management System for Load Balancing through Adaptive Routing
in Multi-Service ATM Networks

Panos Georgatsos
ALPHA Systems S.A., 3, Xanthou str., 1777 78 Tavros, Athens, Greece.

David Griffin
Institute of Computer Science, Foundation of Research and Technology-Hellas, PO Box 1385, Heraklion 717-10, Crete, Greece.

Abstract

Routing is a critical network design issue with the overall aim of maximizing network throughput in terms of service call admissions, while guaranteeing the performance of the network services within specified levels. Routing in ATM-based networks is based on Virtual Path Connections (VPCs). A route is defined as a sequence of VPCs, where each VPC is defined as a sequence of links being allocated a specific portion of link capacity. Multiple routes for a given source-destination (s-d) pair and for a particular service may be available (alternative routing). Alternative routing is desirable since it reduces the likelihood of blocking, it reduces network vulnerability and enhances routing adaptivity to topological and traffic changes. Experimental studies have verified network performance improvement with alternative routing [3],[14]. The definition of a routing policy involves:

The design of an efficient routing policy is of enormous complexity, since it depends on a number of variable and sometimes uncertain parameters. The complexity is even greater, considering the diversity of bandwidth and performance requirements of the services that the network must support. The routing policy should therefore be adaptive to cater for traffic and topological changes.

This paper proposes a hierarchical approach to the routing issue in ATM-based broadband multi-service networks. We show how distributed Route Selection Algorithms embedded within network nodes may be managed by a TMN system, by virtue of a management service called Load Balancing, to increase their adaptivity to network wide conditions and therefore their effectiveness. The paper elaborates on the issues involved, presents specific algorithms and a TMN-compliant management architecture. The proposed management service influences routing decisions by conveying network-wide information and contributes to network load balancing by directing the routing algorithms to route traffic to the least congested network areas. Results regarding the effect of the proposed management system to network operation are also presented.

 

Full paper in IEEE INFOCOM'96, Proceedings Vol. 2, IEEE Computer Society Press, Los Alimitios, CA, USA, 1996.

 

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