A New Recovery Scheme with Reverse Shared Risk Link Group in GMPLS-Based WDM Networks.
ABSTRACT In this study, we present a eccentric end-to-end path selection and recovery scheme that guarantees fast and efficient recovery
of individual and groomed paths in Generalized Multiprotocol Label Switching (GMPLS) based Wavelength Division Multiplexing
(WDM) networks. To this, we propose a novel allocation and restoration strategy called ”Reverse Shared Risk Link Group (RSRLG)”
and demonstrate how this concept can be applied to minimize network reconfiguration in GMPLS networks and to minimize network
recovery time. It is found that only a additional open shortest path first-traffic engineering (OSPF-TE) message is needed
to support the RSRLG scheme and a very fast restorability can be accomplished for a single failure. This paper also has developed
an analytical model and performed analysis for the proposed scheme in terms of two performance factors: mean number of recovery
requests in the system and recovery blocking probability.
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ABSTRACT: We investigate the survivable traffic-grooming problem for optical mesh networks employing wavelength-division multiplexing (WDM). In the dynamic provisioning context, a typical connection request may require bandwidth less than that of a wavelength channel, and it may also require protection from network failures, typically fiber cuts. Based on a generic grooming-node architecture, we propose three approaches for grooming a connection request with shared protection: protection-at-lightpath level (PAL); mixed protection-at-connection level (MPAC); separate protection-at-connection level (SPAC). In shared-mesh protection, backup paths can share resources as long as their corresponding working paths are unlikely to fail simultaneously. These three schemes explore different ways of backup sharing, and they trade-off between wavelengths and grooming ports. Since the existing version of the problem for provisioning one connection request with shared protection is NP-complete, we propose effective heuristics. Under today's typical connection-bandwidth distribution where lower bandwidth connections outnumber higher bandwidth connections, we find the following: 1) it is beneficial to groom working paths and backup paths separately, as in PAL and SPAC; 2) separately protecting each individual connection, i.e., SPAC, yields the best performance when the number of grooming ports is sufficient; 3) protecting each specific lightpath, i.e., PAL, achieves the best performance when the number of grooming ports is moderate or small.IEEE Journal on Selected Areas in Communications 12/2003; · 3.12 Impact Factor
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ABSTRACT: Previous advances in WDM technology are now beginning to shift the focus more toward optical networking and network-level issues. Providing survivability at the optical layer is inherently attractive, but whether it makes practical sense, given similar mechanisms that are already available at the higher layers, poses serious challenges and raises many questions. Today's core network architecture model has functional overlap among its layers, contains outdated functionality, and is too slow to scale. If IP can be mapped directly onto the WDM layer, some of the unnecessary network layers can be eliminated, opening up new possibilities for developing a simple and integrated-protection/restoration scheme that can be coordinated at both the IP and WDM layers. This article presents an overview of existing optical protection/restoration schemes. Then we present a novel mesh-based hybrid optical protection scheme that utilizes multifiber physical links along with a hierarchical OXC structure. An overview of the envisioned IP-centric DWDM-based optical data network architecture is then presented. The basis of how to implement a more direct IP standard-based approach for closer and efficient IP-WDM integration is also discussed. Finally, we articulate a view of how to provide a joint protection/restoration scheme that is coordinated at both the IP and WDM layersIEEE Communications Magazine 07/2000; · 3.66 Impact Factor
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ABSTRACT: This letter proposes a disjoint path selection scheme for generalized multi-protocol label switching (GMPLS) networks with shared risk link group (SRLG) constraints. It is called the weighted-SRLG (WSRLG) scheme. It treats the number of SRLG members related to a link as part of the link cost when the k-shortest path algorithm is executed. In WSRLG, a link that has many SRLG members is rarely selected as the shortest path. Simulation results show that WSRLG finds more disjoint paths than the conventional k-shortest path algorithm.IEEE Communications Letters 10/2002; · 1.16 Impact Factor