The case for source address dependent routing in multihoming

Abstract

Multihoming is currently widely adopted to provide fault tolerance and traffic engineering capabilities. It is expected that, as telecommunication costs decrease, its adoption will become more and more prevailing. Current multihoming support is not designed to scale up to the expected number of multihomed sites, so alternative solutions are required, especially for IPv6. In order to preserve interdomain routing scalability, the new multihoming solution has to be compatible with Provider Aggregatable addressing. However, such addressing scheme imposes the configuration of multiple prefixes in multihomed sites, which in turn causes several operational difficulties within those sites that may even result in communication failures when all the ISPs are working properly. In this note we propose the adoption of Source Address Dependent routing within the multihomed site to overcome the identified difficulties. © Springer-Verlag Berlin Heidelberg 2004.