Distributed QoS Routing with Bounded Flooding for Real-Time Applications

Quality-of-Service (QoS) routing is indispensable to real-time applications on integrated services packet-switching networks. However, existing QoS-routing schemes based on either request ooding or link-state dissemination are not e cient in terms of their message overhead and/or operational cost. This paper proposes a QoS-routing algorithm with bounded ooding which not only dramatically reduces message overhead and operational cost, but also provides good performance. This signi cant overhead reduction is achieved by limiting the search area within which connection-request messages are ooded. Since our scheme is based on limited ooding, it does not require on-demand path calculation nor link-state dissemination, which are often known to be very expensive. In order to limit the search area, we employ a distance table at each node storing hop counts of the shortest paths to all the nodes reachable via its outgoing links. Unlike link-state routing, the proposed scheme only needs network-topology information that changes much less frequently than link-load states. Extensive simulation results have demonstrated the e ectiveness of the proposed scheme in terms of performance, operational cost, and message overhead. Especially, in an ordinary operating condition in which the network's physical topology doesn't change frequently, it is shown to be much better than all the other existing QoS-routing schemes in terms of message overhead and operational cost, while providing reasonably good performance. Index Terms | QoS routing, real-time communication, multimedia communication, ISPN, request ooding, link-state routing.