Abstract-Fast and unambiguous failure localization for shared risk link groups (SRLGs) with multiple links is essential to build fully survival and functional transparent all-optical mesh networks. Monitoring trails (m-trails) has been proposed as an effective approach to achieve this goal. However, each mtrail traverses through each link by constantly taking a wavelength channel (WL), which causes a significant amount of resource consumption. In this paper, a novel framework of alloptical monitoring for SRLG failure localization is proposed. We investigate the feasibility of periodically launching optical bursts along each m-trail instead of supervisory lightpath to probe the set of fiber segments along the m-trail, aiming to achieve a graceful compromise between resource consumption and failure localization latency. The paper will firstly define the proposed framework and highlight the relevant issues regarding its feasibility. We provide theoretical justifications of the scheme. As a proof of concept, the paper formulates the optimal burst scheduling problem via an Integer Linear Program (ILP) and implements the method in networks of all possible SRLGs with up to d = 3 links. A heuristic method is also proposed and implemented for multiple link SRLG failure localization keeping all the assumptions same as the ILP method. Numerical results for small networks show that the scheme is able to localize single and multiple link SRLG failures unambiguously with very small amount of failure localization latency.

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Achieving instantaneous and precise failure localization in all-optical wavelength division multiplexing (WDM) networks has been an attractive feature of network fault management systems, and is particularly important when failuredependent protection is employed. The paper introduces a novel framework of real-time failure localization in all-optical WDM mesh networks, called monitoring-burst (m-burst), which aims to initiate a graceful compromise between consumed monitoring resources and monitoring delay. Different from any previously reported solution, the proposed m-burst framework has a single monitoring node (MN) which launches optical bursts along a set of pre-defined close-loop routes, called monitoring cycles (m-cycles), to probe the links along the m-cycles. Bursts along different m-cycles are kept non-overlapping through any link of the network. By identifying the lost bursts due to single link failure events only, the MN can unambiguously localize the failed link in at least 3-connected networks. We will justify the feasibility and applicability of the proposed m-burst framework in the scenario of interest. To avoid possible collision among optical bursts launched by the MN, we define the problem of collision-free scheduling and formulate it into an integer linear program (ILP) in order to minimize the monitoring delay. Numerical results demonstrate the effectiveness of the proposed framework and the proposed solution.

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