The purpose of the Quality-of-Service (QoS) routing is to search for a network path, in which there are enough resources for setting up a routing connection under certain constraints on delay, cost and other metrics. However, the network state information maintained at every node may be imprecise in the dynamic network environment because of non-negligible propagation delay of state messages, hierarchical state aggregation, and the hidden network information in private network domains. Traditional routing algorithms seldom deal with the problem of imprecise state information. As a result, the performance of QoS routing is degraded with the imprecise state information....[ Read more ]

The purpose of the Quality-of-Service (QoS) routing is to search for a network path, in which there are enough resources for setting up a routing connection under certain constraints on delay, cost and other metrics. However, the network state information maintained at every node may be imprecise in the dynamic network environment because of non-negligible propagation delay of state messages, hierarchical state aggregation, and the hidden network information in private network domains. Traditional routing algorithms seldom deal with the problem of imprecise state information. As a result, the performance of QoS routing is degraded with the imprecise state information.

In this research, we will try to modify and improve an existing unicast routing algorithm called Ticket-Based Probing (TBP) that works with imprecise model by doing more feasible path searches and adding a threshold model. The target of these modifications is to improve the performance metrics of the TBP algorithm in terms of the success ratio of the connection request, the average path cost and the average message overhead of the searches. Therefore, a Modified TBP algorithm with full-sticky threshold is proposed and evaluated to have better performance than the original one. This improved TBP algorithm is also extended to the multicast QoS routing problem with an algorithm called TOURNEY such that an better algorithm for QoS multicast routing having good success ratio, low average path cost and average message overhead, and a high degree of information imprecision tolerances can be developed.