Computer Science Department
School of Computer Science, Carnegie Mellon University
A Comparison of Overlay Routing and
Multihoming Route Control
Aditya Akella, Jeffrey Pang, Anees Shaikh*,
Bruce Maggs, Srinivasan Seshan
A preliminary version of this paper appeared in
Proceedings ACM SIGCOMM 2004,
August 31-September 3 2004, Portland, OR.
Keywords: Performance, availability, multihoming route control,
The limitations of BGP routing in the Internet are often blamed
for poor end-to-end performance and prolonged connectivity
interruptions. Recent work advocates using overlays to effectively
bypass BGP's path selection in order to improve performance and
fault tolerance. In this paper, we explore the possibility that
intelligent control of BGP routes, coupled with ISP multihoming,
can provide competitive end-to-end performance and reliability.
Using extensive measurements of paths between nodes in a large
content distribution network, we compare the relative benefits
of overlay routing and multihoming route control in terms of
round-trip latency, TCP connection throughput, and path availability.
We observe that the performance achieved by route control together
with multihoming to three ISPs (3-multihoming), is within 3-12% of
overlay routing employed in conjunction 3-multihoming, in terms
of both end-to-end RTT and throughput. We also show that while
multihoming cannot offer the nearly perfect resilience of overlays,
it can eliminate almost all failures experienced by a singly-homed
end-network. Our results demonstrate that, by leveraging the
capability of multihoming route control, it is not necessary to
circumvent BGP routing to extract good wide-area performance and
availability from the existing routing system.
*Network Services and Software, IBM T.J. Watson Research Center