Traffic grooming for survivable WDM networks: dedicated protection [Invited]

Abstract

This paper investigates the survivable traffic-grooming problem for optical mesh networks employing wavelength-division multiplexing (WDM) and dedicated protection. We consider the dynamic-provisioning environment where a connection arrives at random, holds for a random amount of time, and then departs. A typical connection request may require bandwidth less than that of a wavelength, and it may also require protection from network failures, typically fiber cuts. Based on a generic grooming-node architecture, we propose two approaches-protectionat-lightpath (PAL) level and protection-at-connection (PAC) level-for grooming a connection request. In this paper, we investigate dedicated protection. In a companion paper (Ou et al. 2003), we investigate shared protection which leads to a substantially different treatment. For dedicated protection, we prove that the problem of provisioning a connection under PAC is N P-complete, propose effective heuristics for both schemes, and define comprehensive performance metrics to compare PAL with PAC with respect to wavelength/grooming-port efficiency. Our findings are as follows. Under today's typical connectionbandwidth distribution where lower bandwidth connections outnumber higher bandwidth connections, PAC outperforms PAL (in terms of bandwidth-blocking ratio, lightpath utilization, and wavelength utilization) if the number of grooming ports is large; however, PAL outperforms PAC (in terms of bandwidth-blocking ratio and grooming-port utilization) when the number of grooming ports is moderate or small.

Flow availability analysis in two-layer networks with dedicated path protection at the upper layer

“…In two-layer networks, service protection for flows can be achieved by using path-oriented protection schemes at the lower or the upper layer [1], [2]. Protection is a proactive recovery procedure, where spare capacity is reserved during the request setup to tolerate a limited set of failure scenarios, e.g., against single fiber link failures in [1], [2].…”

“…Protection is a proactive recovery procedure, where spare capacity is reserved during the request setup to tolerate a limited set of failure scenarios, e.g., against single fiber link failures in [1], [2]. When a failure occurs within the pre-defined set of failure scenarios, the flow is fully protected by switching over to its backup path, i.e., the flow maintains 100% availability.…”

Multi-layer protection in IP-over-WDM networks with and with no backup lightpath sharing

“…The problem of survivable traffic grooming in WDM networks has been considered in [7,8]. In these works, dedicated protection [7] or shared protection [8] is provided at one layer for the connection requests.…”

“…In these works, dedicated protection [7] or shared protection [8] is provided at one layer for the connection requests. Here, backup resource sharing is allowed within the same level, i.e., at the LSP level or at the lightpath level.…”

A Lagrangian-Relaxation Based Network Profit Optimization For Mesh SONET-Over-WDM Networks

“…As an integrated design approach, SONET traffic grooming in WDM networks has received considerable attention recently [4][5][6][7][8][9][10][11][12]. Traffic grooming consists of four sub-problems, which are not necessarily independent: (1) determining the virtual topology of lightpaths over a fibre network; (2) routing SONET traffic onto the virtual topology; (3) routing the lightpaths over the fibre network; and (4) performing wavelength assignments to the lightpaths.…”