Cost analysis in survivable IP/MPLS over WDM networks

The characteristics of various fault recovery schemes applicable to the IP/MPLS over WDM networks are examined from the perspective of initial network cost. A mathematical programming method is proposed to minimize the initial network cost when the LSP protection scheme is utilized as the IP/WLS level fault recovery. The initial network cost for the LSP protection is smaller than that for the shared light-path protection, and it becomes closer to that for the pre-plan type light-path restoration if a certain level of degradation in the transfer quality is permitted after a failure occurrence. Thus, it can be concluded that the LSP protection is the most suitable for the best-effort type traffic while the optical level recovery is still required for the bandwidth guaranteed type traffic. In this paper, a method is presented to limit the transit LSR for the secondary LSP efficiently. However, heuristic methods that can provide the secondary LSP efficiently regardless of the traffic distribution should be clarified for the LSP protection scheme.