Shared risk link group failure restoration with in-band approximate failure localization ?
This paper proposes a novel failure recovery framework for multi-link shared risk link group (SRLG) failures in optical mesh networks, called failure presumed protection (FPP). The proposed framework is characterized by a failure dependent protection (FDP) mechanism where the optical layer in-band failure identification and restoration tasks for route selection are jointly considered. FPP employs in-band monitoring at each node to obtain on-off status of any working lightpath in case the lightpath is terminated at (or traversing through) the node. Since the locally available failure status at a node may not be sufficient for unambiguous failure localization, the proposed framework reroutes the interrupted lightpaths in such a way that all the suspicious links which do not have 100% restorability under any SRLG failure are kept away. We claim that this is the first study on FDP that considers both failure localization and FDP survivable routing. Extensive simulations are conducted to examine the proposed FPP method under various survivable routing architectures and implementations. The results are further compared with a large number of previously reported counterparts. We will show that the FPP framework can overcome the topological limitation which is critical to the conventional failure independent protection method (e.g., shared path protection). In addition, it can be served as a viable solution for FDP survivable routing where failure localization is considered.
shared risk link group failure dependent protection in-band failure monitoring shared protection