A practical approach to minimizing delays in Internet routing

Abstract

We present a practical approach to Internet routing that provides near-minimum delays over multiple loop-free paths to destinations. The new protocol, which we call NEAR-OPT, obtains multiple loop-free paths to destinations using long-term delay measures, and allocates destination-oriented flows over such paths using short-term delay measures to minimize delay. We compare the performance of NEAR-OPT with traditional single-path routing and the only known adaptation for dynamic networks of Gallager's (1977) minimum-delay routing algorithm. Using actual Internet traffic traces and other traffic source models, we show that NEAR-OPT provides delays comparable to the lower bounds achievable with Gallager's algorithm for static networks, provides lower delays than implementations of Gallager's algorithm in networks subject to fractal traffic, and renders far smaller delays and better use of resources than traditional single-path routing. NEAR-OPT does not depend on any global constant and is completely distributed, making it easy to implement as a loop-free "distance-vector" protocol similar to Cisco's EIGRP.