Limited scope probing: a distributed approach for QoS-based routing

Two new QoS-based unicast routing algorithms for high-speed internetworks are proposed as part of this work. Both algorithms, Limited-Scope Probing (LSP) and Limited-Scope Hop-by-Hop Probing (LSHP) use the route update messages generated by the Open Shortest-Path-First (OSPF) algorithm to create hybrid routing tables. The LSP and LSHP are semi-distributed routing algorithms. They assume that the network "state" information maintained by the OSPF is accurate in "close" vicinity of the maintaining node. Therefore, the LSP and LSHP propose to use source-based routing techniques to route along paths that are "centrally" computed by the node. The extent of the vicinity can be set by an appropriate parameter. Extensive simulations are performed to compare our algorithms with existing QoS-based unicast routing algorithms.