On the Scalability of Path Exploration Using Opportunistic Path-Vector Routing

It can be argued that, BGP, de-facto inter-domain routing protocol, provides fairly stable routes. Path stability is a desired product of that limited level of deterministic performance of BGP. To attain this performance level, BGP relies on keeping up-to-date (aggregated) global information by incurring the cost of control traffic and delayed convergence. In this work, we developed an Opportunistic Path-Vector (OPVR) protocol which provides nice trade-offs between path stability, routing scalability and path quality to enable flexible inter-domain level routing services. Our approach is to redefine routing problem as a set of smaller scale problems which can be solved locally without requiring a global coordination but local communication. We also provide guidelines on how to solve these localized routing problems efficiently. Our analysis show that our method provide a good compromise between scalability and opportunity through smartly randomized (non-deterministic) choices. Our experiments with OPVRs on Internet AS-level topology show us that OPVRs can provide non-deterministic, scalable path exploration mechanisms with reasonable control traffic cost.