Perspectives on Router Buffer Sizing: Recent Results and Open Problems

The past few years have witnessed a lot of debate on how large Internet router buffers should be. The widely believed rule-of-thumb used by router manufacturers today mandates a buffer size equal to the delay-bandwidth product. This rule was first challenged by researchers in 2004 who argued that if there are a large number of long-lived TCP connections owing through a router, then the buffer size needed is equal to the delay-bandwidth product divided by the square root of the number of long-lived TCP flows.