An integrated end-to-end QoS anycast routing on DiffServ networks

Anycast is the point-to-point communication between a single client and the nearest destination server identified by an anycast address in traditional best-effort networks such as the Internet. Conversely, an anycast service in a QoS-based network is required to choose a path with bandwidth guarantees and to select a server with capacity guarantees. This paper proposes an approach which integrates both a network layer anycasting service and an application layer anycasting service to select a path and server that satisfies the client QoS constraint in DiffServ networks. In order to perform a path selection algorithm, the proposed protocol uses the idea of residual capacity to select all paths which match the client bandwidth requirement. In order to perform the server selection process, each server resource management (SRM) uses the server weight of each server to select the best server that has sufficient capacity for the client request. Furthermore, the design of multiple SRMs eliminates the single-point-of-failure problem and increases reliability in a DiffServ network. The simulation results have shown that the proposed protocol has much faster server response times and has the lowest request blocking rate compared to other existing protocols, especially in the case where the traffic load is high.