Computer Science Department
School of Computer Science, Carnegie Mellon University


Endpoint-Based routing Strategies for Improving
Internet Performance and Resilience

Aditya Akella

September 2005

Ph.D. Thesis


Keywords: Internet routing, Border Gateway Protocol, performance bottlenecks, overlay networks, route control, Moore's law, Internet topology

Internet access speeds of large enterprises and educational institutions have improved dramatically over the past few years. However, this higher-speed connectivity is still ineffective at providing end-users with good download performance and robustness from service interruptions. This arises due to the prevalence of constrained links with little spare capacity inside Internet Service Provider (ISP) networks.

In this dissertation, we first investigate the location, latency and traffic load characteristics of network links that limit the Internet performance of well-connected end-networks. More importantly, we show how end-networks can employ a clever Internet route selection technique, called Multihoming Route Control, to avoid these performance bottlenecks and obtain much better Internet performance. Using Internet-scale measurements conducted over Akamai”Ēs content distribution infrastructure, we show that by multihoming to three ISPs, and intelligently scheduling transfers across the ISPs, an end-network could potentially improve its Internet round-trip times (RTTs), throughputs and reliability by up as much as 30%.

We also compare the Internet performance and reliability from route control against more powerful route selection paradigms such as overlay routing. We show that the RTTs and transfer speeds from multihoming are within 5-10% of overlay routing. While multihoming cannot offer the nearly perfect resilience of overlays, we show that it can eliminate almost all failures experienced by a singly-homed end-network. We also describe the design and performance evaluation of a route control system that can be deployed by large multihomed enterprises. We show that, in practice, simple route control techniques can offer Web performance within 10% of the optimal performance from multihoming.

Finally, we investigate whether, in the future Internet, techniques such as route control or overlay routing can still provide good end-to-end performance in the face of higher access speeds and a vastly different traffic mix. We show that the structure of the Internet (i.e., a power law degree structure at the ISP level), together with the routing protocol (i.e., BGP), will convert certain keys portions of the network into persistent bottlenecks. We then consider modifications to the ISP-level interconnections to guarantee good end-to-end performance in the future Internet.

We believe that the contributions in this thesis significantly advance the state-of-the-art of techniques for improving Internet performance and resilience. Further, this dissertation highlights important guidelines for the design of inter-domain routing protocols and peering architectures.

181 pages

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