Number : WUCSE-2004-82 2004-1204 Link Buffer Sizing : a New Look at the Old Problem

In this paper, we revisit the question of how much buffer an IP router should allocate for its output link. For a long time, the intuitive answer of setting the buffer size to the bitrate-delay product has been widely regarded as reasonable. Recent studies of interaction between queueing at IP routers and TCP congestion control proposed alternative answers. First, we expose and explain contradictions between existing guidelines for link buffer sizing. Then, we argue that the problem of link buffer sizing needs a different formulation. In particular, the chosen buffer size should accommodate not only common versions of TCP but also UDP traffic. Besides, our new formulation of the problem contains an explicit constraint of not engaging IP routers in any additional signaling. We conclude the paper by outlining a promising direction for solving the reformulated problem. Link Buffer Sizing: a New Look at the Old Problem Sergey Gorinsky Anshul Kantawala Jonathan Turner Applied Research Laboratory Department of Computer Science and Engineering Washington University in St. Louis St. Louis, MO 63130-4899, USA gorinsky,anshul,jst @arl.wustl.edu