FCS Rx Errors

[Jarred M]

So I have a 3500yl with a gbic installed in port 45 and I have been getting errors on it. I pasted the sh int below this is around 3 minuets after I cleared the statistics. It is showing a lot of FCS Rx errors and the only information I have found about that is a duplex mismatch which of course isn't possible on a fiber link. How should I go about troubleshooting this?

Status and Counters - Port Counters for port 45

Name : Annex Trunk
Link Status : Up
Totals (Since boot or last clear) :
Bytes Rx : 65,374,820 Bytes Tx : 117,950,605
Unicast Rx : 66,904 Unicast Tx : 104,308
Bcast/Mcast Rx : 519 Bcast/Mcast Tx : 767
Errors (Since boot or last clear) :
FCS Rx : 367 Drops Tx : 0
Alignment Rx : 0 Collisions Tx : 0
Runts Rx : 0 Late Colln Tx : 0
Giants Rx : 4 Excessive Colln : 0
Total Rx Errors : 371 Deferred Tx : 0
Rates (5 minute weighted average) :
Total Rx (bps) : 6610952 Total Tx (bps) : 7133104
Unicast Rx (Pkts/sec) : 168 Unicast Tx (Pkts/sec) : 226
B/Mcast Rx (Pkts/sec) : 1 B/Mcast Tx (Pkts/sec) : 1
Utilization Rx : 00.66 % Utilization Tx : 00.71 %

[Richard Brodie_1]

It may be just noise on the link, that's what the CRC is there to guard against.

Have a look at the lengths and type of fibre & transceivers, see if they are within specification. Check for damaged patch cables etc. See if it's lossy both ways.