Multihoming performance benefits: An experimental evaluation of practical enterprise strategies

Multihoming is increasingly being employed by large enterprises and data centers as a mechanism to extract good performance from their provider connections. Today, multihomed end-networks can employ a variety of commercial route control products to optimize performance over multiple ISP links. However, little is known about the mechanisms employed by such products and their relative trade-offs. In this paper, we propose and evaluate a wide range practical schemes that could go into the design of a route control device and analyze their trade-offs. We implement the proposed schemes on a Linux-based Web proxy and perform a trace-based emulation of their relative performance benefits. We show that both passive and active monitoring based techniques are equally effective and could improve Web performance by about 25% when compared to using a single provider. Another key observation is that the conventional practice of employing historical measurement samples to monitor and predict ISP performance could, in fact, result in sub-optimal performance.