ISP and Egress Path Selection for Multihomed Networks

Overview

Multihoming has been used by stub networks for several years as a form of redundancy, improving the availability of Internet access. More recently, Intelligent Route Control (IRC) products allow multihomed networks to dynamically switch parts of their egress or ingress traffic between ISPs, also improving cost and performance. IRC products assume that the set of upstream ISPs is given and fixed. Typically, however, a multihomed network has several ISP choices and the actual selection of ISPs can significantly affect cost, availability, and performance.