Path probing relay routing for achieving high end-to-end performance

We present an overlay network routing scheme, called path probing relay routing (PPRR), which is capable of promptly switching to alternative paths when the direct paths provided by the underlying IP networks suffer from serious performance degradation or outage. PPRR uses a randomized search algorithm to discover available alternative paths and employs an end-to-end, on-demand probing technique to determine their quality. To assess the effectiveness of PPRR, we conduct performance simulations using four sets of real-world traces, collected by various research groups at different times and places. Our simulation results show that the performance of PPRR is comparable to that of a typical link state relay routing algorithm. Compared with the latter, PPRR has lower probing overhead in the sense that the overhead remains constant as network size grows. In particular, PPRR avoids the need to flood the overlay network with link state updates.