Introduction

Abstract

Routing in the current Internet focuses primarily on connectivity and typically supports only the “best-effort” datagram service. The routing protocols deployed such as OSPF [43] use the shortest path only routing paradigm, where routing is optimized for a single metric such as hop count or administrative weight. While these protocols are well-suited for traditional data applications such as ftp and telnet, they are not adequate for many emerging applications such as IP telephony, video-on-demand and teleconferencing, which require stringent delay and bandwidth guarantees. The “shortest paths” chosen for the best-effort service may not have sufficient resources to provide the requisite service for these applications. Furthermore, with the explosive growth of the Internet traffic, the shortest path only routing paradigm of the current Internet also leads to unbalanced traffic distribution — links on frequently used shortest paths become increasingly congested, while links not on shortest paths are underloaded.