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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 ?

4 REPLIES
Anonymous
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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.

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

Have you got any other Cisco equipment connected to the 3Com switch? if you have then its possible that a CDP packet from this devices is being forwarded through the 3Com switch (due to it being a Multicast packet and the 3Com switch flooding it throughout the layer-2 network).

I have this also: I have a Catalyst 2900 connected to a 3Com switch on a 100Mb-full-duplex link, connected to the 3Com switch is a Cisco 2503 router; its Ethernet port at 10Mb-half-duplex, both Cisco devices report CDP/duplex mismatches due to thier CDP messages being forwarded by the 3Com switch.

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

Have you got any other Cisco equipment connected to the 3Com switch? if you have then its possible that a CDP packet from this devices is being forwarded through the 3Com switch (due to it being a Multicast packet and the 3Com switch flooding it throughout the layer-2 network).

I have this also: I have a Catalyst 2900 connected to a 3Com switch on a 100Mb-full-duplex link, connected to the 3Com switch is a Cisco 2503 router; its Ethernet port at 10Mb-half-duplex, both Cisco devices report CDP/duplex mismatches due to thier CDP messages being forwarded by the 3Com switch.

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

Have you got any other Cisco equipment connected to the 3Com switch? if you have then its possible that a CDP packet from this devices is being forwarded through the 3Com switch (due to it being a Multicast packet and the 3Com switch flooding it throughout the layer-2 network).

I have this also: I have a Catalyst 2900 connected to a 3Com switch on a 100Mb-full-duplex link, connected to the 3Com switch is a Cisco 2503 router; its Ethernet port at 10Mb-half-duplex, both Cisco devices report CDP/duplex mismatches due to thier CDP messages being forwarded by the 3Com switch.

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