Abstract

Routing diversity has been identified as essential for network robustness and traffic engineering. The Internet possesses by its very nature a large path diversity. However this diversity cannot be fully exploited due to BGP limitations, which only keeps one single route for each available prefix. Despite some previous works in the area, no operational and non-disruptive architecture have been proposed yet to allow the networks to better exploit Internet path diversity.
This paper proposes one step in this direction, focusing on the interconnection between an Autonomous System (AS) and its Internet Service Provider (ISP). We propose the use of a so-called “Map-and-Encap” scheme to bypass current BGP limitations in order to use arbitrary paths. With this scheme, an ISP may propose its rich path diversity (at least partially) to its customers, in order to perform advanced traffic engineering (e.g. fast recovery, load balancing...) based on richer and more flexible path selection policies (e.g., considering price, performance or stability of routes). To assess the potential benefits of the proposed architecture, we evaluate the potential route diversity that a Tier 1 may offer to its stub clients, based on different possible route selection policies (i.e. which routes are offered to its customers). We also analyze the overhead that is created at the control-plane (routing updates received by the mapping database) and that may impact the data-plane (path changes that may be caused by some route withdrawals/updates). Our evaluation shows that the increase in diversity has a controllable and acceptable overhead. It also gives some insights into efficient deployment strategies.