If you have all the same port speed, small buffers are fine. If you have 100G and 1G ports, you'll need big buffers wherever the transition to the smaller port speed is located.

While the larger buffer there you are likely to be severely impacting application throughput.

On Fri, Apr 9, 2021 at 9:05 AM Mike Hammett <nanog@ics-il.net> wrote:
What I've observed is that it's better to have a big buffer device when you're mixing port speeds. The more dramatic the port speed differences (and the more of them), the more buffer you need.

If you have all the same port speed, small buffers are fine. If you have 100G and 1G ports, you'll need big buffers wherever the transition to the smaller port speed is located.

From: "Dmitry Sherman" <dmitry@interhost.net>
To: nanog@nanog.org
Sent: Friday, April 9, 2021 7:57:05 AM
Subject: Trident3 vs Jericho2

Once again, which is better shared buffer featurerich or fat buffer switches?
When its better to put big buffer switch? When its better to drop and retransmit instead of queueing?

Thanks.
Dmitry