All-Optical Monitoring Path Computation Based on Lower Bounds of Required Number of Paths

Abstract

To reduce the cost of fault management in the alloptical networks, it is investigated to detect the degradation of optical signal quality solely at the terminal points of all-optical monitoring paths. The monitoring paths must be routed so that all single-link failures can be localized using routes information of monitoring paths where signal quality degradation is detected. However, routes computation for the monitoring paths that satisfy the above condition is time consuming. This paper proposes a procedure for deriving the lower bounds of the required number of monitoring paths to localize all the singlelink failures, and an efficient monitoring path computation method based on the derived lower bounds. The proposed method repeats the route computation for the monitoring paths until feasible routes can be found, while the assumed number of monitoring paths increases starting from the lower bounds. With the proposed method, the minimum number of monitoring paths with the overall shortest routes can quickly be obtained when the possible terminal nodes of monitoring paths are arbitrarily given. Thus, the proposed method can minimize the operational cost of monitoring the degradation of signal quality and can reduce the overhead traffic transferred through the monitoring paths.

Network-Wide Local Unambiguous Failure Localization (NWL-UFL) via Monitoring Trails

“…The studies [5], [7], [8] focused on failure localization using close-loop supervisory lightpaths (or termed m-cycles), and [10]- [12] for open-loop supervisory lightpaths (or termed mtrails). The study in [5] targeted at minimizing the number of MLs, which is determined by analyzing the connectivity among the 2and 3-connected components in the topology.…”

“…Note that the performance evaluation and analysis on the number of m-trails has been extensively conducted in the past, while very little understanding was gained regarding the cover length of an m-trail solution. Further, since NWL-UFL does not rely on any upper layer signaling effort for alarm code dissemination, the length of alarm code becomes not as critical as that in the previous research [7][8][9][10][11][12][13][14][15][16][17].…”

“…Several UFL schemes have been proposed [4], including simple and non-simple m-cycle [5]- [8], m-trails [5], [9]- [12], directional m-trail [6], [13], [14], and m-trail with loopback switching [9], [15]. Although they differ from each other by adopting a specific monitoring structure and design objectives, a common feature is that each monitoring structure is alloptically pre-cross-connected as a supervisory lightpath dedi-cated for the failure localization purpose.…”

“…Using m-trails with bi-directional lightpaths in all-optical WDM networks has been proposed [9], [12], [15], [16]; and all these studies set the destination node of each m-trail as the only node that can detect the status of the m-trail. This results in a fact that alarm dissemination is needed upon a failure event mostly via flooding and dedicated failure notification based on network layer signaling, such that the alarm code can be formed at a remote site or any network node in order to localize the failure.…”

Fast failure localization in all-optical networks with length-constrained monitoring trails

“…The running time of the heuristic is further improved with some meta heuristic approaches, such as TabuSearch [12], and simulated annealing [13]. Recently several more heuristics have been proposed in [14]- [17]. Essentially optimal construction with log 2 (|E| + 1) + O(1) m-trails for UFL of single link failure were given for several special topologies: for complete graphs [7] with 4 + log 2 (|E| + 1) m-trails, for a 2D grid network with two rows and arbitrary many columns [18] with b = 0.42 + log 2 (|E| + 1) m-trails.…”