Catalyst 3500 Series and error prone situation

[akuechler]

Hi,

i have a some wierd errors in a site where some cat3500 are situated. I have 2 3508g and 6 3524 at this site. 3524s are redundantly connected to both 3508g. so far for the topology - but i don't think that's part of the problem.

Problem is - I see a large number of collisions on the ports (no they are not connected to hubs but to individual stations). Some of these problems could be identified as errors during the Speed/Duplex detection phase. As a result all links where placed in defined speed and duplex settings (ports + Host NICs).

But even on ports that show the same speed and duplex on Switch and Host I still see collisions, crc and input errors. cabling has been checked and is within limits.

anybody any idea where i could continue to look at ?

Thanks

[jezerski]

Does your fiber plant run anywhere close to large sources of EMF? This can include high wattage power sources, elevator shafts, other heavy equipment that draws a lot of power or produces EMF.

You can also run a test by putting a host in the same room as the switch and see if still sees the CRC and other errors.

Also, check your host NIC configuration. I have found, especially with Windows hosts, that "default" on the NIC is not always equal to auto/auto for link negotiation. You might also look and see if the NIC vendor has newer drivers.

Finally, if you are using patch panels for your hosts check the punch downs themselves. It may sound funny, but I have seen more than a few installations that had stripped back and unwound the CAT 5 cables for many inches in order to more easily punch them down to the back of the patch panel. This causes a huge amount of cross-talk and could be the source of your problems.

HTH

-Joe