Enhanced Linear Protection Switching Methods Supporting Dual Node Interconnection in Packet Transport Networks

In this paper, we discuss the issues of supporting protection switching in multiple recovery domains (MRDs). In MRDs, dual node interconnection (DNI) between two adjacent domains is essential to provide reliable services for customers whose traffic traverses multiple domains. Existing linear protection switching solutions in packet transport networks, such as multiprotocol label switching-transport profile (MPLS-TP) and Ethernet, support protection of an end-to-end flow between two end nodes in a recovery domain; however, they do not provide DNI capability between two recovery domains. We propose a DNI scheme with linear protection switching technology and analyze its advantages. In the case of a large number of connections affected by a single failure in MRDs protected by linear protection, traffic recovery can be delayed owing to the signaling associated with excessive simultaneous signal fail triggers. We design a collective interconnection message (CIM) scheme that improves the performance of linear protection DNI (LP-DNI) in MRDs and confirms that the CIM mechanism reduces restoration time significantly. By extensive simulations on link and node failures scenarios, we investigate different combinations of LP-DNI and existing ring protection processes to establish the influence of service resiliency in MRDs.