Cisco connected to HP switch: CDP duplex mismatch

[ATC]

The following problem appeared when we established a fiber link between a new Cisco 2960 and an older HP ProCurve switch.

The system log on the Cisco switchen was full of messages like this:
*Mar  3 00:24:25.071: %CDP-4-DUPLEX_MISMATCH: duplex mismatch discovered on GigabitEthernet0/4 (not half duplex), with SEP001DA290F.

The system log on the HP switch contained nothing relevant.

Both interfaces were initially configured to auto/1000, none of the switches allow half/1000 and the media converters in between only supported 1000 Gbps. Both switches reported the link as full/1000 but the error messages kept appearing.

Attempting to manually configure both ends to full/1000 caused no change in the symptoms alone.

[ATC]

The problem is most likelycaused by incompatibility between CDP on these particular Cisco and HP switch models. The solution was to disable CDP on the Cisco port in question, while manually configuring to full/1000 to be on the safe side:

interface GigabitEthernet0/4
 description uplink ENGAHE
 switchport mode trunk
 speed 1000
 duplex full
 no cdp enable
end

This appears to have solved the problem, there are no more error messages and the users report that the network now appears to be working properly.