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We study an idea for efficient integrated protection of an IP over WDM network using the spare capacity of span-protecting p-cycles to provide protection against both optical link failures and router node failures in the IP/MPLS layer. Preciously, networks using span-protecting p-cycles were de signed from the point of view of a single-layer physical transport network. Also separately, it has been known how to plan capacity allocations to IP-layer logical links to support controlled levels of bandwidth oversubscription on transiting traffic flows through a failed router or ATM node. To address both failure types, however; it is unattractive to simply combine the two investments in added protection capacity. Accordingly, we have studied ways to plan a 100% span-restorable set of physical-layer p-cycles so that very high levels of transiting traffic flow can also be restored upon MPLS router node failure, with controlled worst-case over subscription of LSP capacity allocations. In test cases it was found that the spare capacity provided by span-protecting p-cycles can provide a high level of node protection depending on the strategy used for exploting the p-cycle, capacity. We think this leads to novel and efficient strategies for multi-service and multi-layer survivable traffic engineering, and bandwidth management. [ABSTRACT FROM AUTHOR]

Dense wavelength division multiplexing (DWDM)-based optical networks that are assumed to employ exactly two working fibers uniformly on every span are matter of recent interest in the field of telecommunication. An interesting and highly efficient strategy for protection of such networks is to use, if possible, a single dark-Fiber p-cycle formed on a Hamiltonian cycle. It has been showed that in a homogeneous Hamiltonian network, a Hamiltonian p-cycle is the most efficient overall solution, although interestingly it does not always correspond to the individually most efficient p-cycle that can be formed. The article also considers p-cycle planning in non-Hamiltonian but homogeneous networks and introduce the concept of a semi-homogenous network, specifically linked to the p-cycle concept. The proposed semi-homogeneous class of network actually realizes the theoretical lower bound on span-restorable networks in terms of network redundancy. Such networks also provide a strategy to accommodate certain patterns of capacity growth beyond a homogenous network without any increase in protection capacity. The work also demonstrates and explains why a single Hamiltonian p-cycle is not as efficient as a specifically optimized set of individual p-cycles in a "capacitated" network where the working capacity on each span varies in a general way.

Proposes a design-refinement approach to increase the capacity efficiency of span-restorable mesh networks on sparse facility graphs. Information on the meta-mesh graph; Advantages of wavelength-division-multiplexing networking elements; Practical aim in the design of survivable transport networks; Description of several forms of network protection; Conventional design of span-restorable mesh networks.