duplex mismatch on a cisco ip phone

[vladrac-ccna]

Hello,

Not sure if this is a bug or something else.

I'm receiving the following msg on the syslog, but both phone and switch are correctly set to AUTO negotiate the duplex and speed.

Dec 21 11:37:01.107 EST: %CDP-4-DUPLEX_MISMATCH: duplex mismatch discovered on FastEthernet3/3 (not full duplex), with SEP001360C3E06D Port 1 (full duplex).

After a interface recycle (shut/no shut) it stop.

Any ideas?

Vlad

[gogasca]

Hi Vald you have already posted this query, And have recieved and reply in IP Telephony forum.

[mkoci]

Turn off CDP on that port. I believe there might be a bug within CDP and the ip phone.

[ariancapri]

Sir,

Which IP Phone u r using can u clarify this.

Regards,

Arian

[vladrac-ccna]

CISCO IP PHONE 7940 Series.

[sandonen]

I wouldn't turn CDP off. I believe it is needed. I ran into this issue myself and discovered that in some cases, hard setting the switch/phone causes and issue. Set the phone/switch to auto/auto and the phone should connect at 100/full with no errors.