3550-12G problem with gigabit connection

[ajit.shah]

Greetings all

I have two new 3550-12g running 12.1(19)EA1c IOS.

I am trying to connect both switches using inbuilt

RJ45 10/100/1000 port (# 11, 12). The trunk works fine

if i use 100Mbps connection crossover cable. The same does not work with 1000mbps.

Am I missing something ?

thx

Ajit

[thisisshanky]

Are the links set to auto or hardcoded to 100 Mbps ?

Have you checked your gigabit crossover cable to see if its crossed properly ? Gigabit uses all 4 pairs.

[ajit.shah]

Well If I hardcode the speed at 100Mbps it works.

If I use straighthrough cable with speed/duplex auto

(default config) why It's not autonegotiating to 1000Mbps ? you are right I might have to use different

crossover for gigabit.

thx

[thisisshanky]

Hope this post helps

http://forum.cisco.com/eforum/servlet/NetProf?page=netprof&CommCmd=MB%3Fcmd%3Dpass_through%26location%3Doutline%40%5E1%40%40.1dd6b935/0#selected_message

You have to use a diff cross over to work at 1000 Mbps. At 100 Mbps it uses only 2 pairs. At 1000 Mbps all 4 pairs are used.