Introduction to Quality of Service Routing Approaches and Algorithms Seminar Topic:

It is used to define the service class that a packet should receive at the end of each switch. It also used to allocate certain amount of resources. It also sorts the incoming packets to their respective classes. It controls the amount of traffic to the each class. These steps are followed again to each and every switch, or at least all bottleneck routers.

Why we use QOS routing. It is basically used for dynamic determination of feasible paths. It also optimizes the resource usage. And improve the performance degradation.

Routing strategies and approaches: it includes source routing for feasible paths that computed by the source node.

 In distributed routing they have paths that are computed by distributed computation.

 In hierarchical routingtopology are created by clustering nodes into groups that form logical nodes.

Heuristic approach: it uses famous Chen and nahrstedts algorithm, and jaffe’s algorithm that proposes non-linear path length function.

 They use three metrics: available bandwidth, propagation delay, hop count. For selecting path they use the technique of bellman-ford pre-computation, it computes the bandwidth for all counts. They also use Dijkstra on demand and Dijkstra pre-computation. For forwarding purpose they use hop-by-hop method.

It has some problems also that arises during QoS routing: it creates routing with in accurate information. Networks are dynamic and have aggregation problem also. Information is hidden and the calculation is not approximate. Ithas some inter-class effects in QoS routing. It uses bandwidth reservation to prevent the starvation of low priority traffic.

Conclusion:it is require finding some new path for sufficient resources available. QoS traffic reserve resources while major of them do not. User requirement are successful, and satisfied. They use shortest path algorithms like dijkstra algorithm and bellman-ford algorithm.

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