Efficient QoS routing for differentiated services EF flows

Expedited forwarding (EF) is the differentiated services class of service that provides high quality transmission with node bounded delay. Nevertheless, in order to obtain a bounded network delay it is necessary to compute a route that meets the required end-to-end delay. Therefore, we study the requirements (bandwidth, buffer and delay) for a new EF connection. As detailed in the paper, with these constraints the routing algorithm is a NP-complete problem. Therefore, we present an efficient routing scheme that has low polynomial computational cost. Finally, the evaluation of this routing shows that is as efficient as using the exact routing algorithm.