01-10-2012 01:10 PM - edited 03-07-2019 04:16 AM
Good evening gentlemen,
today I witnessed a cisco n5k that stopped playing fair. For a yet unkown reason several interfaces started to show output errors all begining within the same second. While i instantly thought this would be a wiring issue I began to ask myself what an output error actually means. Can anybody help me with that question? Google usually brings up output drops, not regular output errors. So what is it and how can a 10G fiber interface even detect that there is a problem without receiving what it was sending?
I'd appreciate your input on that matter
bye
Pille
Solved! Go to Solution.
01-10-2012 07:07 PM
Hi Pille,
Output errors can be caused by many things. N5k is cut-through so it is starting to send packet before it get it's all from the sender. So you may need to check if you see any input errors on the other interfaces (on N5k or FEX)accompanying the output ones. It can also be related to jumbo frame coming trough with Jumbo option not set up.
For jumbo you can refer to:
To check it in more details can you please share following logs:
Thanks,
Nik
01-10-2012 07:07 PM
Hi Pille,
Output errors can be caused by many things. N5k is cut-through so it is starting to send packet before it get it's all from the sender. So you may need to check if you see any input errors on the other interfaces (on N5k or FEX)accompanying the output ones. It can also be related to jumbo frame coming trough with Jumbo option not set up.
For jumbo you can refer to:
To check it in more details can you please share following logs:
Thanks,
Nik
01-11-2012 10:43 AM
Thanks Nik,
your suggestion about the input errors on another interface were spot on. We had fcs inbound errors on one of the n5k vpc peer link interfaces, that's probably why so many different interfaces were struck by outgoing errors at the same time. A change of the affected sfp solved our problem
Once again thanks Nik for your help.
Regards
Pille
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