Scalability of routing advertisement for QoS routing in an IP network with guaranteed QoS

In this paper, we are going to focusing on the scalability of routing advertisement schemes for establishing connections with on demand end-to-end QoS requirements. The correctness of QoS-based routing mainly depends on the accuracy of routing information such as link residual bandwidth. Advertising network resource availability could introduce the routing scalability problem, due to its frequent change. Within each routing area, each router needs to constantly advertise its resource availability information and this information is flooded into entire routing domain. We investigate the trade-off between scalability and correctness of QoS routing. We consider periodic and dynamic (threshold and exponential-class) intra-domain QoS routing advertisement schemes combined with the use of clamp down timer. We propose a simple "crankback with cache" scheme by modifying the traditional crankback, and compare their effects on different situations. We define a performance metric to reflect the correctness for each scheme. Our measurement aims to evaluate the correctness and scalability in the environment of inter-domain QoS routing. Using our simulations, we provide heuristic solutions of achieving good performance and scalability for implementing QoS routing.