Intervlan High Latency

[gauravprakash]

Hi,

We have few vlans created and also have a mix of 3548 and 2548 switches, also we have 6009 as central switch with MSFC. Users of VLAN 4 complain of high latency when they access the VLAN 1 servers. We use PVST. Also , the truncking protocol is both isl and dotq.

Please help

[gauravprakash]

when we move the same systems to VLAN 0 , the latency is very low.

[Kevin Dorrell]

VLAN 0?

[gauravprakash]

sorry vlan 1.when the systems are moved to serevr vlan , the latency issue is no more

[Kevin Dorrell]

We could be looking at a problem on the trunks, or we could be looking at a CPU or switching path problem on the MSFC. So how should we eliminate these.

Do you get good performance in the VLAN1<->VLAN1 case even if the test machines are on different access switches?

I think we need to look at whether the traffic goes through the trunks in each case: VLAN1<->VLAN4 and VLAN1<->VLAN1. For these tests, are the server and the client on different switches? Is it that case that on different VLAN the traffic goes through the trunk, but on the same VLAN it goes straight from port to port.

If you get the latency in the VLAN1<->VLAN1 case when the test machines are on different access switches, then it is a trunk problem. If you get have good performance in the VLAN1<->VLAN1 case even with the test machines on different access switches, then the VLAN1<->VLAN4 problem is due to the MSFC.

Does that make sense?

Kevin Dorrell

Luxembourg