We have a 6506 with Sup 720 and two wsx-6748-ge-tx modules. The switch runs in the native mode. it's been configured for about 24 vlans each mapping a class C network. the average cpu utilisation on the switch is about 2% and it never exceeds 10%. Maximum bandwidth utilisation we ever see on any of the ports is about 400 Mbps.
However at times when we have sustained TCP traffic of 40 Mbps to a remote site, we see ping times between some local subnets exceeding 80ms, which seems abnormal and inexplicable. Does anyone have an idea what could be causing it? How do you troubleshoot such a problem?