runt errors

[dragec]

I had strange situation. I had several LAN ports on my 4506 switch that had input errors (runt), less then 0,1%. Port was fixed to 100M, full duplex. When I removed fixed settings and let devices negotiate speed and duplex, they agreed on 100M and full duplex, but this time, after that I had no errors. Can someone explain this?

thanks!

[glen.grant]

That means the far end was set as auto and you had your end hardcoded which is a mismatch and would cause the errors you are seeing. Both ends must match to be correct , both need to be auto or both need to be hardcoded.

[dragec]

hmmm ... are you sure? If one side is auto and second one is fixed ... then auto side should "agree" with fixed, if possible of course!?

thanks!

[sourabhagarwal · Accepted solution]

check this URL if it gives you any clue.

http://www.cisco.com/warp/public/473/46.html#gen_tr_10_100

rate if it does ...

[glen.grant · Accepted solution]

Wrong , if one side is auto then the other side must be auto . The switch can always sense speed ok but can not negotiate the duplex without the other side being auto also . If the far end is hardcoded to 100/full the auto side will sense the speed at 100 ok but cannot sense the duplex thus defaults that end to 100/half thus you have a speed/duplex mismatch where one end is 100/full (hardcoded) and the auto side is 100/half by default because it could not sense the duplex because the far end was hardcoded, so it is both ends as auto or you have to hardcode both ends to the specific speed and duplex like 100/full . This is one of the major reasons for slowness and errors on a port because poeple don't understand that concept.