Research On Anycast QoS Routing In MPLS Networks

Anycast is a new Internet service.With anycast service, a client can reach the most appropriate server, which is one of the servers that accept datagrams for anycast address.Anycast has numerous potential applications,and is recognized as an useful service.However,many technological problems have limited its acceptance by the community. Routing for anycast service is very important, which decides usability and efficiency of the service directly. With the emergence of multimedia services, the requirements of Web services have exceeded the network capacity. Anycast services such as video on demand, IP telephony and other real-time services have been seriously affected. Quality of Service (QoS) can improve network services and meet different requirements of applictions by network resources management. Anycast QoS Routing has become an important research subject.MPLS (Multi protocol Label Switching) combines the flexibility of IP technology and the rapid exchange of ATM technology, and is regarded as a core technology in the next generation networks. Explicit routing, traffic engineering and QoS routing are the most significant superiority of MPLS. For guaranteeing Anycast QoS and enhancing the utilization of network resources, we propose a study of Anycast QoS routing based on MPLS.An Anycast Routing Algorithm guranteeing QoS in MPLS Networks (ARQM)is proposed.It pre-computes anycast path with least hop numbers.This path can fulfill bandwidth constraint by link state routing protocol from the destination node(server) of an anycast datagram to its source node(client).ARQM reserves bandwidth on LSP using constraint routing-label distribution protocol(CR-LDP). The simulation results indicate that ARQM results about delay and data loss-rate are good ,and the algorithm also banlance the server load to some extent.The network load balancing of Anycast service is studied. An Anycast Routing Algorithm Supporting traffic engineering (ART)is proposed . ART is based on Minimum Interference Routing schema. When selecting a path to meet client's requests and having the least interference, ART uses the information regarding the source - destination (SD)pairs to reduce interference between current requests and future requests for the establishment of Label Switched Paths and reserving resource. ART uses the values on the direction from the servers of an anycast datagram to client,and assigns links weight associated with link residual bandwidth,server load,and interference on the link of all SD pairs.ART get the best path by using Dijkstra algorithm in the end. The simulation results indicate that ART can balance network load,and optimize network resource utilization.