Re: cdp enable/disable?

In article <464db8bc$0$36725$892e0abb@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>,
Doug McIntyre <merlyn@xxxxxxxxx> wrote:

"Lisa Casey" <lisa@xxxxxxxxxxx> writes:
I have a Cisco 2610 (I think) router connected to a switch connected to my
network. We recently received a couple of VOIP phones (Cisco IP-Phone 7940
series). When I plug these into the network, my syslog receives the
following error from the router once a minute:

05-15-2007 16:39:39 Local7.Warning hope.jellico.com 387: 10w3d:
%CDP-4-DUPLEX_MISMATCH: duplex mismatch discovered on Ethernet0/0 (not full
duplex), with SEP001AE22A943D Port 1 (full duplex).

I googled it and found some suggestions to just turn cdp off on the
Ethernet0/0 interface of the router.

This would get rid of the messages I'm receiving, but do I really want to
do that? Are the messages I'm seeing real error messages indicating a
problem I should resolve, or are they just informational, letting me know
of something that is harmless?


No, you probably don't want to do that. You do have a duplex mismatch
between the VOIP phone and the switch. ...

Probably not. I'd guess there's a non-Cisco switch between the phone
and the router. The router sees a CDP neighbour reporting a full duplex
connection (to the switch) but receives the messages on an interface
which is running half duplex. It therefore complains. If there were a
CDP-speaking switch between them those particular messages wouldn't get
through.

Sam
.

Relevant Pages

  • Re: Router or Switch
    ... > Should I buy a switch or a router? ... A hub will only support 10Mb/s half duplex. ...
    (microsoft.public.windowsxp.general)
  • Re: How to upgrade a small network
    ... > I'm leaving the Linksys and DSL modem all at one end of the house though; ... :) The new switch doesn't provide any sort of protection ... nor does the physical distance from the router. ... a 10/100 switch (full duplex), ...
    (comp.os.linux.networking)
  • Re: two NICs and speed issues
    ... > So if you disconnect the modem the transfers are fast on the ... > will give you a listing of each interface. ... > connections you want to have full duplex set. ... > between the NIC and the switch you will see the error count increase ...
    (Fedora)
  • Re: Mysterious problem on my clients Windows Server 2003 Network
    ... I changed the switch today and I'm still getting the bad checksums. ... cable is configured to 100Mbps full duplex and the other end to ... would lose connection to the server and/or connection to the internet, ...
    (microsoft.public.windows.server.networking)
  • Re: Odd Duplex Problem - transmit speed
    ... I have a GE medical imaging device that GE tells me HAS to be ... Easy enough, affer the switch config, I check the GE Imaging device, ... and plug a small dlink hub into that port. ... A HUB cannot operate at full duplex, it is a hub, it only runs at half ...
    (comp.dcom.sys.cisco)