Quality-of-Service Routing for Tra c with Performance Guarantees

Quality-of-Service (QoS) routing tries to select a path that satis es a set of QoS constraints, while also achieving overall network resource e ciency. We present initial results on QoS path selection for tra c requiring bandwidth and delay guarantees. For tra c with bandwidth guarantees, we found that several routing algorithms that favor paths with fewer hops perform well. For tra c with delay guarantees, we show that for a broad class of WFQ-like scheduling algorithms, the problem of nding a path satisfying bandwidth, delay, delay-jitter, and/or bu er space constraints while at the same time deriving the bandwidth that has to be reserved to meet these constraints, is solvable by a modi ed version of the Bellman-Ford shortest-path algorithm in polynomial time.