A study of IP routing stability for GMPLS‐based next‐generation backbone network

GMPLS (Generalized Multi‐Protocol Label Switching) is considered promising as the basic technology for forming the next‐generation ISP (Internet Service Provider) backbone network. In an IP backbone network based on GMPLS, the optical layer and the packet layer are vertically integrated and operate in close collaboration. It is due to this collaborative operation of multiple layers that integrated network control such as path setting in the optical layer according to the IP traffic in the packet layer and fast recovery from faults is realized. However, there is a danger, due to the similarity of functions in the two layers or to mismatch of the parameters, that collaborative operation between layers may affect the stability of IP routing in the packet layer. This situation is mostly due to the fact that the time granularity in the change of path state in the optical layer is finer than that of the IP routing protocol processing in the packet layer. This paper discusses route stability in the packet layer during collaborative operation of layers. The situation is analyzed by simulation and a method of improving stability is proposed.