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%CDP-4-DUPLEXMISMATCH:Full/half duplex mismatch detected

HAs anyone seen a problem when connecting a catalyst 4006 to a 3com corebuilder , when both ends are set to 100Meg Full duplex and are showing connected, I occasionally get the error message "%CDP-4-DUPLEXMISMATCH:Full/half duplex mismatch detected on port 3/33"

There are no errors being reported on the ports.

Is it due to CDP being enabled ?


Re: %CDP-4-DUPLEXMISMATCH:Full/half duplex mismatch detected

The mismatch was caused by Switch port defaulting to half duplex because it sensed its Link Partner was no longer performing auto-negotiation.It is important to note that this message is created by the Cisco Discovery Protocol (CDP), not the 802.3 auto-negotiation protocol. CDP can report problems it discovers but it typically doesn't automatically fix them. Rememnber that CDP is a Cisco propietary protocol not supported by 3Com switches.

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Re: %CDP-4-DUPLEXMISMATCH:Full/half duplex mismatch detected

I had the same message some time ago. Cisco devices exchange some of their parameters via CDP. Cisco switches analyze the messages and do not forward them to other ports. Other brands ( eg your 3C Corebuilder ) do not understand these CDP messages and forward them to the other ports of the switch.

The CDP message your cat 4006 receives, comes from a different cisco device that is behind the 3com switch. The duplex parameters reported by CDP not match. If they are correct on your 3C switch, there is no problem.

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