A Fuzzy QOS Routing Algorithm for Communication Networks

One of the key issues in providing end-to-end quality of service (QoS) guarantees in today´s networks is how to determine a feasible route that satisfies a set of constraints. In general, finding a path subject to multiple constraints is an NP-complete problem that cannot be exactly solved in polynomial time. Accordingly, several heuristics and approximation algorithms have been proposed for this problem. Many of these algorithms suffer from either excessive computational cost or low performance. In this paper, we propose a fuzzy-logic based algorithm for finding a bandwidth-delay-constrained path by Dijkstra´s shortest path algorithm. The main objective of fuzzy QoS routing algorithm (FQRA) is to reduce packet loss and increase overall network utilization. To achieve this objective, the algorithm at first, eliminates all links with a bandwidth less than the requirement so that any paths in the resulting graph will satisfy the bandwidth constraint. Then, a new single parameter with the aid of fuzzy logic is generated from inputs bandwidth and delay. The shortest path calculated by Dijkstra´s algorithm based on new metric. Simulation results show that FQRA outperforms several earlier algorithms in terms of overall network utilization and packet loss. The worst-case computational complexity of this algorithm is within a logarithmic number of calls to Dijkstra´s shortest path algorithm, equal with O(n²) for a network graph with n nodes