UUNET Routing issues

Thu Oct 3 22:32:32 UTC 2002

Thus spake "Iljitsch van Beijnum" <iljitsch at muada.com>
> At 155 Mbps you need 32 MB worth of buffer space to arrive at a delay like
> this. I wouldn't put it past ATM vendors to think of this kind of
> over-enthusiastic buffering as a feature rather than a bug.

Traditionally, it's ATM switches that have tiny buffers and routers that have
excessive buffers.  ATM networks have closed-loop feedback and ingress policing
mechanisms to handle this scenario; IP networks just throw buffers at the
problem and hope it works.

> Does anyone have any thoughts on optimum buffer sizes?

The "correct" amount of buffer space for a link is equal to its bandwidth-delay
product.  Unfortunately, this requires per-link testing and configuration on the
part of the operator, which is extremely rare.

S