slow lan please help

carl_townshend · ‎09-13-2007

Hi all, We have got a massive problem on our lan, there was a loop in the network a few days back, which we fixed. However since then, the whole network has been going slow, I mean we are talking 20 to 60 ms delay times when pinging my access switches. the cpu on my dist switches are normal and I can see many broadcasts on vlan 1, any ideas ?

cheers

Carl

paul.matthews · ‎09-13-2007

What you need to do first is check where the spanning tree root bridges are. It is possible that if you added a device and things went haywire that it became the spanning tree root.

Ideally your core switches should be the root, and if using something like HSRP the root should be the same place as active router.

Then check the state of links - really you should be aware of which links should be blocked - make sure the blocks are where you expect.

Then you need to look at the various interfaces that join switches and make sure they are actually running at the speed and duplex settings you expect, and all are clean - ie you are not getting a load of FRC errors on a link for example.