A new distributed QoS routing algorithm based on Fano's method

Providing a guaranteed quality-of-service (QoS) is essential to many real-time applications. The existing distributed QoS routing algorithms are based on either shortest path or flooding and both tend to have high message overhead. A new distributed unicast QoS routing algorithm based on Fano's decoding method is studied. Fano's decoding method is a technique used in error control coding and it attempts to trace an optimal path probabilistically. The similarity of various aspects of Fano's decoding method to a QoS routing algorithm and the benefits it can provide encourages us to investigate the possibility of using it in QoS routing. This is the first known attempt to modify an error control technique using Fano's decoding method for the purpose of QoS routing in fixed wired networks. Simulation results demonstrate the effectiveness of the proposed algorithm in terms of message overhead and success ratio (% of paths obtained that satisfy the given QoS constraints). It is shown that the message overhead in the proposed algorithm is reduced compared to flooding based algorithms while maintaining a similar success ratio. Message overhead is also reduced compared to distance vector based algorithms for all but very sparsely connected networks, while success ratio is not compromised. Nodal storage is also considerably lower than for most other contemporary QoS routing algorithms.