CDP-W-DUPLEX_MISMATCH CBS350

[dragosneagu95]

Hello everyone!

I have the next switch CBS350-48P-4X with this version: 3.0.0.69.

I have a problem with CDP on the ports where I have IP phones. It gives me the next warning:

%CDP-W-DUPLEX_MISMATCH: Duplex mismatch detected on interface gi1/0/10.

The IP phones are not from Cisco, they are from Yealink. I have tried speed 1000 and duplex full, but no result. I know that I can configure the no cdp log mismatch duplex on the interface to resolve the issue.  But why the warning shows up? What do I need to configure? What do I miss?

I have enabled cdp run global on the switch with cdp device-id format hostname.

The configuration on the gi1/0/10 is a smart ports and has the next config:

interface GigabitEthernet1/0/10
    storm-control broadcast level 10
    storm-control multicast level 10
    port security max 10
    port security mode max-addresses
    port security discard trap 60
    spanning-tree portfast
    spanning-tree bpduguard enable
    switchport mode trunk
    switchport access vlan 100
    switchport trunk allowed vlan 1,100
    macro description ip_phone_desktop
    !next command is internal.
    macro auto smartport dynamic_type ip_phone_desktop

VLAN 100 is the Voice and VLAN 1 is the Native.

Thank you!

[balaji.bandi]

%CDP-W-DUPLEX_MISMATCH: Duplex mismatch

Suggestions :

First i would check the port what speed negotiating, may be try 100MB lower speed.

Only cisco phone can work with CDP - so disable CDP and test it.

I look odd on your configuration :

You configured Trunk and access vlan so on.

To Trim down the config, if you looking Data and Voice on that port ( try avoid default VLAN 1 always - create new VLAN in place of VLAN1)

check below link :

https://www.cisco.com/c/en/us/support/docs/smb/switches/Cisco-Business-Switching/kmgmt-2258-voice-vlan-configuration-on-the-cbs250-350-series-switches.html

Either you disable smart port and configure voice and data vlan as traditional manner or remove access port config.

[dragosneagu95]

Thanks for the answer Balanji!

I've changed the native VLAN 1 (data vlan in my example) with another native VLAN and the problem persists. The only solution it was to disable the duplex mismatch with the command no cdp log mismatch duplex.

[balaji.bandi]

Good to know - so the fix is to apply "no cdp log mismatch duplex" thank you sharing the information.