Study On Routing Selection Algorithm With Differentiated Services Function

These are many routing algorithms based on MPLS traffic engineering, a large number of which are only select paths for the traffic with the bandwidth request. Traditional traffic engineering Algorithms, e.g. PBR, DBR, MIRA, are all routing selection algorithms with bandwidth guarantee, viz. they can only manage the QoS operation with the bandwidth request, and not deal with the Best-Effort operation. Actually, a great number of operations are Best-Effort operation in networks.The traffic engineering solution ( DS– TE ) based on DiffServ provides different services function, but it needs system administator to select bandwith for each service first, then uses CSPF algorithm to select routing path for services; how to make the path is based on the system administator's experience or the demand of each service. This method can not balance the whole bandwidth of the network to each service and lose sight of the performance of the network. An extension to routing selection algorithm called Routing Selection Algorithm with Services Differentiation Consciousness is proposed in this paper. Off-line multipath Analysis is the essential part of the algorithm, it created some useable label-switch- paths for each source-node to destination-node; when the operations set in, the on-line routing algorithm will create the LSP for each the QoS and Best-Effort operations using different strategy, viz. select the short path which is close to the bandwidth request of the traffic for QoS, to satisfy the requests of demand and low delay, and also to avoid refusing the posterior QoS traffic which demand is high into the network; for Best-Effort traffic select the path which residual bandwidth is abundance, to avoid congestion and load balance.Using Ns-2, the simulation result shows that the new online routing algorithm significantly outperforms the CSPF (Constrained shortest path first) , which greatly increases the throughput of the Best-Effort traffics, and simultaneously guarantees the bandwidth and acceptable-ratio of the QoS traffics. Off-line algorithm also reserves some bandwidth for QoS traffic, results in not rejecting the request in an irresponsible way.