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Professional Discussions => Routing and Switching => Topic started by: TheGreatDoc on February 07, 2016, 06:24:45 AM

Title: From where the errors come from...
Post by: TheGreatDoc on February 07, 2016, 06:24:45 AM
Hi NFS Pro Dudes,

Im saying for a time big peaks of errors on some ports of my switches.

How can I debug from where the errors come from and what is causing them?
Title: Re: From where the errors come from...
Post by: SimonV on February 07, 2016, 07:07:13 AM
What sort of errors are you seeing exactly?
Title: Re: From where the errors come from...
Post by: TheGreatDoc on February 07, 2016, 07:32:51 AM
Graphed by cacti from default interface errors/discards template.

Title: Re: From where the errors come from...
Post by: deanwebb on February 07, 2016, 08:10:28 AM
If you could post the errors, we could take a look at them. Just modify machine names and IP addresses if those would reveal anything that shouldn't be revealed, and we'll look at them.
Title: Re: From where the errors come from...
Post by: TheGreatDoc on February 07, 2016, 08:28:45 AM
Quote from: deanwebb on February 07, 2016, 08:10:28 AM
If you could post the errors, we could take a look at them. Just modify machine names and IP addresses if those would reveal anything that shouldn't be revealed, and we'll look at them.
And that is exactly my question. Where can i look further than a "show interface"?
Title: Re: From where the errors come from...
Post by: srg on February 07, 2016, 09:15:57 AM
What platform is this? (this kind of counters are often very platform specific)
Title: Re: From where the errors come from...
Post by: TheGreatDoc on February 07, 2016, 09:24:01 AM
Its a Cisco C3750. But as far I can see, the errors showed in graph are not in the "show interface" command.....
Title: Re: From where the errors come from...
Post by: GeorgeS on February 08, 2016, 03:40:20 AM
play a bit with the show controller command, i am a bit busy this morning and do not have the time to find  a c3750 in our network.  sh controller ethernet (something) should be what are you looking. 
Title: Re: From where the errors come from...
Post by: dlots on February 08, 2016, 10:03:50 AM
Errors come mostly from duplex mismatches and bad cables in my experiance
Title: Re: From where the errors come from...
Post by: TheGreatDoc on February 11, 2016, 04:17:31 AM
The thing is that the errors/discards are not constant and the dont come in the heavy traffic timeline.

Title: Re: From where the errors come from...
Post by: icecream-guy on February 11, 2016, 06:37:12 AM
Quote from: TheGreatDoc on February 11, 2016, 04:17:31 AM
The thing is that the errors/discards are not constant and the dont come in the heavy traffic timeline.

It could also be EMF radiation, e.g. cables are run too close to fluorescent lights, so when someone goes and turns a light on, someone else network becomes slow.   

I've seen this when I worked in a large warehouse where the network cables were run up in the top of the warehouse along with the lighting and electrical with wires run down around electrical conduit to the workstations...and they wondered why the network was slow...

Title: Re: From where the errors come from...
Post by: matgar on February 11, 2016, 06:55:27 AM
Quote from: TheGreatDoc on February 07, 2016, 09:24:01 AM
Its a Cisco C3750. But as far I can see, the errors showed in graph are not in the "show interface" command.....
You could give this a try.

sh controllers ethernet-controller GigabitEthernet x/y/z


I also found this list of commands for trouble shooting links.

Show interface status | inc connected
Test cable-diagnostics tdr interface <>
Show cable-diagnostic tdr interface <>
Show interface <>
Show interface <> counters
Show interface <> counters errors
Show interface counter errors
Show controller Ethernet-controller <>
Show platform pm if-numbers
Show controllers Ethernet-controller port-asic statistics
Show platform port-asic stats drop <>