I started getting a duplex mistmatch error

All of a suddent, I'm getting these error messages and I'm not sure why.  It's not giving me the IP address of the other switch, I'm not sure what the T46.... number referenced is?
Any thoughts?

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DanNetwork EngineerAsked:
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JustInCaseCommented:
There are 3 typical root causes for duplex mismatch:
1. duplex manually misconfigured (rare)
2. duplex auto negotiation failure bugs
3. one side is manually configured with duplex full and other side is autonegotiating duplex.

So, generally, both sides supposed to be configured statically with duplex command or both sides need to be autonegotiating duplex. If one side is configured with duplex 100, other side will fail back to duplex a-half. If you run into bug regarding autonegotiation process (or software bug regarding duplex), try manual configuration of duplex on both sides. Sometimes speed need to be configured statically for duplex negotiation to be successful.
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DanNetwork EngineerAuthor Commented:
They both say a-full and a-1000 or something, I have to look, but they both match.  I will try to configure both the same manually.  From the error, it doesn't tell me what the 2nd  switch is?
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JustInCaseCommented:
Since cdp reports an error, it could be issue with cdp implementation. Try to check neighbor via cdp
show cdp neighbor Gi1/0/2
show cdp neighbor Gi1/0/7
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nociSoftware EngineerCommented:
The T46... is the nodename of the neighbour.
And you can follow the cable from port 2 (Gi1/0/2) and port 7 (Gi1/0/7) to see which switch it is.
Of check the configuration documentation of the site to see where it goes.

Or use show cdp neighbor  to get theri IP addresses (if cdp has been enabled on both sides).

For fixing: check the setup of the ports either both Auto (and if that is the current state) appearantly auto config may fail then setup for Fixed speed & Duplex.
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DanNetwork EngineerAuthor Commented:
both, ports 2 and ports 7 are end users, they are computers or a voIP phone attached, they are not switches.
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DanNetwork EngineerAuthor Commented:
So both ports were auto full and 1000.  I checked the Voip phones, and they are set to 1000 and full duplex.  So I configured the switch to 1000 and full duplex, and I'm still getting those error messages.  I have the exact same switch in multiple locations, with the same IOS version, so I wonder why this issue is only happening on this switch?

Any other ideas?  Maybe I can restart the switch, but I doubt that will help.
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JustInCaseCommented:
Which switch and phone models? IOS versions?
There are different bugs regarding auto negotiation duplex/speed process. Maybe it is know bug between specific devices.
You can try to upgrade/downgrade one of switches/phones and to check if there is a still problem with duplex mismatch.

If  everything else fails, you can open ticket with Cisco TAC support.
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DanNetwork EngineerAuthor Commented:
So far so good, what I did  on both sides, the phones and the switch, I changed the config to manual, 1000 and full, and then back to auto, and it seems like it's working as the errors have stopped.
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nociSoftware EngineerCommented:
The phones may also have a switch on board for a connected PC how it that influencing the configuration?
Maybe you should check cables if there has been put a hub in between or some other equipment.
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