Protection Switching Methods for Point‐to‐Multipoint Connections in Packet Transport Networks

In this paper, we discuss the issues of providing protection for point‐to‐multipoint connections in both Ethernet and MPLS‐TP‐based packet transport networks. We introduce two types of per‐leaf protection–linear and ring. Neither of the two types requires that modifications to existing standards be made. Their performances can be improved by a collective signal fail mechanism proposed in this paper. In addition, two schemes — tree protection and hybrid protection — are newly proposed to reduce the service recovery time when a single failure leads to multiple signal fail events, which in turn places a significant amount of processing burden upon a root node. The behavior of the tree protection protocol is designed with minimal modifications to existing standards. The hybrid protection scheme is devised to maximize the benefits of per‐leaf protection and tree protection. To observe how well each scheme achieves an efficient traffic recovery, we evaluate their performances using a test bed as well as computer simulation based on the formulae found in this paper.