Throughput Guaranteed Restorable Routing Without Traffic Prediction

Two-phase routing, where traffic is first distributed to intermediate nodes before being routed to the final destination,has been recently proposed [10], [11], [18] for handling widely fluctuating traffic without the need to adapt network routingto changing traffic. Pre-configuring the network in a traffic independent manner using two-phase routing simplifies networkoperation considerably. In this paper, we extend this routing scheme by providing resiliency against link failures throughtwo different fast restoration mechanisms local (link/span) based and end-to-end (path) based. We view this as importantprogress towards adding carrier-class reliability to the robustness of the scheme so as to facilitate its future deploymentin Internet Service Provider (ISP) networks. The main contribution of the paper is the development of fast combinatorial algorithmsfor routing under the scheme with link and path restoration mechanisms so as to minimize the maximum utilization of any linkin the network, or equivalently, maximize the throughput. The algorithms developed are Fully Polynomial Time ApproximationSchemes (FPTAS) for any given > 0, an FPTAS guarantees a solution that is within a (1 + )-factor of the optimum and runsin time polynomial in the input size and 1/ . To the best of our knowledge, this is the first work in the literature thatconsiders making the scheme resilient to link failures through pre-provisioned fast restoration mechanisms. We evaluate theperformance of link and path restoration (in terms of throughput) and compare it with that of unprotected routing.