Semi-dynamic routing protocols for anycast packet forwarding

Routing is a fundamental mechanism in any IP communication network, which takes place at the network layer. Anycasting is a new mechanism introduced recently for IP packet delivery from a sending node to any one of a group of receiving nodes with the same IP addresses. Any one and only one node from the group will reply to the sender. The birth of IPv6 has enabled service locating using anycasting method, which was not possible in IPv4. Generally packets are routed by static or dynamic routing method. Packets can be routed by using single path routing (SPR), multiple path routing (MPR) or integrated routing (SPR&MPR) techniques. In this paper we have implemented and analyzed single path routing tree algorithms with two routing strategies: static and semi-dynamic. Bellman ford algorithm was used to develop our new semi-dynamic anycast routing mechanisms. Routing tree formation (RTF) protocol that we implemented includes anycast group based shortest path first (AGBSPF) algorithm, load-balanced AGBSPF algorithm, load propagation algorithm for server load announcement and core-based tree (CBT). Besides we have also implemented packet forwarding (PF) algorithms to perform well with the RTF where it helps to forward the packets based on the costs and server load. Semi-dynamic method has proved to be better then the static where it provides alternative path for packets transmission in the case of link or node down.