10-07-2013 04:44 PM - edited 03-07-2019 03:53 PM
At work recently I have run into a problem where on my 6500 switches I see, continuous ports errors accumulating, the network does not seem to be slow but the errors are in the millions for more then 70% of all ports. This is happening on many switches throughout the enterprize. At my job we have old equipment dating back to the year 2000. The ios versions are 5.1 to 5.3. If need be I can post some output tomorrow. But I'm thinking it is an old IOS and needs to be upgraded either on the SUPS or the chassis themselves as well. Please advice what I should do. Thanks guys.
10-07-2013 04:53 PM
the network does not seem to be slow but the errors are in the millions for more then 70% of all ports.
You are not talking about "Total Output Drops", are you?
10-07-2013 05:08 PM
No, Im talkin about single-collisions, multiple-collisions, when I do a show port 3/7 for example.
10-07-2013 05:12 PM
Collisions generally means that you've got duplex issues. Are duplex hard-coded on the interfaces?
10-07-2013 05:14 PM
Yes they are. For users its 10/half. For printers its 100/Full. For wireless access points they auto sensed usually at 100/Full.
10-07-2013 05:17 PM
its 10/half.
If you (intentionally) configure your interface as "half duplex" then this will guarantee you get collision errors, period.
It's not a "Cisco thing". It's the ethernet standard.
One more thing, you've hard-coded the printer to be "full duplex"? Modern NICs (printers, PCs, etc), you don't need to hard-code their speed and duplex settings. Just leave them be and these NICs tend to behave themselves, unlike in the olden days.
10-07-2013 05:21 PM
So basically If an interface is configured at half duplex going through a cat 5 cable, some will most certainly collide. So what would be an optimum configuration for ports that cause no collisions with cat 5 cables for regular users?
10-07-2013 05:24 PM
We have new Xerox printers that require speeds to be configured at 100/full because their responce times slow down tremendeously at 10/half
10-07-2013 05:41 PM
So basically If an interface is configured at half duplex going through a cat 5 cable, some will most certainly collide.
Yes, guaranteeed.
So what would be an optimum configuration for ports that cause no collisions with cat 5 cables for regular users?
Auto speed, auto duplex.
We have new Xerox printers that require speeds to be configured at 100/full because their responce times slow down tremendeously at 10/half
Those are extreme cases. Mostly, you leave speed and duplex settings to auto so they can sort themselves out.
10-07-2013 11:34 PM
I can't see any reason why you would have anything configured as HALF DUPLEX.
Hard set these ports to FULL DUPLEX and the correct SPEED.
You may have to do this on both ends if you are connecting to another SWITCH/ROUTER
When troubleshooting duplex should be your first place to look.
For all work switch ports that connect to works stations at my work we use speed 100 duplex full. They don't need 1GB at the desktop so I don't give it to them. Take the change that our 1GB uplinks from the switches can be flooded by a single user aswell.
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