06-23-2008 05:58 PM - edited 03-05-2019 11:46 PM
Hi,
I have this weird scenario:
I have 2 cisco switches connected using a cross cable
C3560 FA0/22 <-> C2950 FA0/24
Both ports have configured to be in full duplex, 100 mbps mode. However, recently, I see messages that complain that duplex mismatch. The problem was resolved by resetting the duplex to auto on both sides.
Jun 24 09:11:08: %CDP-4-DUPLEX_MISMATCH: duplex mismatch discovered on FastEthernet0/24 (not full du
plex), with JDAP_DEV_FS1 FastEthernet0/22 (full duplex).
Details of switch configurations:
Current configuration : 133 bytes
!
interface FastEthernet0/24
description Computer Room-Rack2 JDAP_DEV_FS1 X.X.X.X f0/22
switchport mode trunk
speed 100
end
Current configuration : 118 bytes
!
interface FastEthernet0/22
description To Computer Room-Rack2 JDAP_DEV_FS1_ES4 x.x.x.x fa0/24
speed 100
end
Switch version:
IOS (tm) C2950 Software (C2950-I6Q4L2-M), Version 12.1(22)EA4a, RELEASE SOFTWARE (fc1)
Cisco IOS Software, C3560 Software (C3560-IPBASE-M), Version 12.2(25)SEB2, RELEASE SOFTWARE (fc1)
Anyone has any idea what can I do further to isolate the cause?
06-23-2008 06:08 PM
Hardcode both sides as the following and it should get rid of the message. Between cisco switches leaving them as auto for both speed and duplex will work fine also . If you don't specify the duplex it will usually default to half duplex .
speed 100
duplex full
06-23-2008 06:12 PM
Hi Glen,
Sorry, that my question has confused you. The configurations that you have seen are the modified ones. Previously, both sides have been hardcoded to be in speed 100, full duplex.
06-23-2008 06:18 PM
It may be getting getting confused by the fact that you have one side hardcoded as a trunk and the other side is a access port .
06-23-2008 11:50 PM
i hope glen's answer is right
06-30-2008 01:24 AM
I hope so, as this is first time I am seeing this. :)
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