Off-piste QoS-aware routing protocol

QoS-aware routing protocols have been the focus of much attention in the past decade. This is due to the interesting challenges posed by the problem of QoS routing, in the absence of precise information - or even partial and altogether imprecise information. We present a new QoS-aware routing protocol, OPsAR, which achieves very good performance results at a very reasonable cost, in terms of memory and messages, OPsAR is based on the multi-path routing approach, but constrains the number of paths used and leverages on previous resource reservation attempts. Every reservation attempt - successful or not - results in an update to the knowledge-state recorded at all the nodes that had participated in those attempts. This knowledge helps in avoiding network bottlenecks and coping with congested path when they are encountered. We present extensive simulation results and even compare ourselves favorably with a protocol that explores all possible paths.