Implementing Stochastic Preplanned Restoration with Proportional Weighted Path Choice in IP/GMPLS/WDM Networks

IP over WDM networking and related GMPLS standards, appear to be attractive solutions for today's and future Internet applications due to their ability to handle multiple traffic flows independently of one another, and reserve wavelengths to carry a large number of aggregated flows. Another advantage of these solutions is the simplified IP over WDM stack, that provides all the vital network functionalities, including network reliability. The paper investigates the use of the stochastic preplanned restoration scheme with proportional weighted path choice (SPR-PW) to design reliable and efficient IP/GMPLS/WDM networks. Upon the disruption of a primary flow determined by a link failure, one of the associated preplanned secondary paths is readily selected by the SPR-PW scheme to continue the flow transmission. The selection of the secondary path is performed on a probabilistic base, without requiring time-consuming coordination among the restoration attempts of the disrupted flows. As a result of this stochastic selection, the SPR-PW scheme has the potential to yield short recovery times. In addition, the SPR-PW required signaling, upon and before the failure occurrence, is limited, which makes SPR-PW a scheme suitable for highly dynamic traffic scenarios, in which flows are subject to frequent changes. The paper describes the SPR-PW scheme as it is applied to cope with physical link failures, depicts a possible implementation of such a scheme using standard IP/GMPLS signaling capabilities, and numerically demonstrates two properties of the SPR-PW scheme, i.e., low blocking probability and short restoration times.