An Approach to Distributed Multi-Path QoS Routing

The principal objective of the present research work is to attain QoS in routing mechanism. For this, a distributed QoS multi-path routing algorithm has been designed that finds multiple disjoint paths in a distributed way from one source to one destination. These multiple paths satisfy the given QoS requirements. The proposed algorithm DQM (Distributed QoS Multi-Path algorithm) uses local information to find multiple QoS paths as the global state information available for making routing decisions is often inaccurate in a lively environment and inaccuracy can be the cause of QoS failure. The QoS parameters that have been considered are residual bandwidth and delay. Firstly the algorithm obtains all the paths which satisfy the QoS criteria in a fully distributed fashion. At destination, these paths are again processed to identify mutually exclusive disjoint paths. Among overlapping paths, those paths will be selected whose combination of bandwidth and delay is better than other. To achieve this, fuzzy logic has been used. By applying fuzzy logic a new single metric is obtained from the input’s bandwidth and delay of the calculated paths. Based on this value, the paths are filtered to disjoint paths. Since the paths obtained at destination are already constrained paths and further these paths are refined into most optimal disjoint paths using the concept of fuzzy logic, thus the proposed strategy provides both constrained and optimal paths.