CDP Error Message on 3550-48 EMI

[rkollar59]

Greetings,

I have a brand new 3550-48 Port EMI switch. After performing the initial startup configuration, via terminal, I receive the following error message....

"CDP-4-duplex mismatch discovered on FastEthernet0/1

(not half duplex), with SEP000D29CED364 Port 48 (half duplex."

Can someone please what this is about? How to fix it? Thanks.

[Georg Pauwen]

Hello,

if you have nothing connected to the switch, this could be a bug. Which IOS version are you running ?

Regards,

GP

[rkollar59]

GP,

The IOS version is 12.1(22)EA1a.

RK

[duncanm]

Is anything else connected to the switch with CDP? This message tends to pop up when you have two CDP devices connected with one running CDP v1 and one running CDP v2.

Duncan

[rkollar59]

Duncan,

I have an ISP provided Cisco 1760 Router, a SMC 7008ABR Router(for NAT and Firewall; but soon to be removed and replaced with a PIX515E. The 3550 is currently connected to the SMC.)

[duncanm]

Have you manually set the speed/duplex on each side?

[Kevin Dorrell]

This message can often happen when you have two Cisco devices connected across a non-Cisco switch. Each Cisco device has its link to the switch, and has negotiated/fixed its own individual duplex settings with the switch. But because the non-Cisco switch is transparent, the Cisco devices can see each other via CDP. (A Cisco switch would terminate the CDP).

There is actually a bug report about it that suggests some workarounds:

Workarounds:

------------

1. Configure the global command "no cdp advertise-v2".

- or -

2. Disable CDP on the complaining interface(s).

- or -

3. Change to "Error" Syslog level.

http://www.cisco.com/cgi-bin/Support/Bugtool/onebug.pl?bugid=CSCdp30476

Kevin Dorrell

Luxembourg