Server Fault is a question and answer site for system and network administrators. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I'm looking at purchasing a network switch, and the only spec I'm not sure of is one specifying "buffer memory" per port. What is that used for?

share|improve this question

It is used to buffer packets in a store-and-forward switch. More buffers are not neccesarily better, and can even make things worse. See the Buffer Bloat phenomenon. Cut-through switches provide much lower latency and do not use buffers.

share|improve this answer
Note though that for some workloads, larger port buffers can offer significant performance improvements. iSCSI SAN traffic, for example. – Chris Thorpe Sep 30 '11 at 14:52
So I should just ignore that particular spec? – Billy ONeal Sep 30 '11 at 15:00
@Chris Thorpe, it shouldn't help at all, and due to the buffer bloat problem, could make things worse. More buffered packets leads to more latency. – psusi Sep 30 '11 at 15:02
@Billy ONeal, I would look for cut-through switches that don't use buffers. – psusi Sep 30 '11 at 15:03
@psusi: Hmmm... I don't see anything like that available anywhere. Then again, I'm talking about a small (~8 port) switch. Everything available seems to be store-and-forward. – Billy ONeal Sep 30 '11 at 15:23

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.