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New Member

Inter switch trunking

Got 2 switches connected together as follows

port f0/26 on a cisco WS-C2950C-24 to port g0/48 on a cisco WS-C2960G-48TC-L

They are auto sensing speed and duplex and I cannot find a command to tie them down.

The problem is that WS-C2950C-24 is auto sensing the duplex as full and WS-C2960G-48TC-L is auto sensing the duplex as half

I have coppied the show ver, show int and the interface config from both switches in a notepad attachment

I hope someone can help me with this

Cisco Employee

Re: Inter switch trunking


Can you please let us know the GBIC module you are using on 2960G Switch. Your 2950 switch port is 100 base FX and I think you also have a GBIC on 2960G as well.

-amit singh

New Member

Re: Inter switch trunking

Hi there yes the GBIC in the 2960G is a GLC-FE-100FX

Cisco Employee

Re: Inter switch trunking

Hello Chris,

It looks like the SFP on 2960 port doesnot support "auto-negotiation" and falling back on half-duplex. Please try configuring the duplex as full under the SFP interface configuration.

Config t

Switch(config)#Interface ge x/y

Switch(config-if)#media-type sfp

Switch(config-if)#duplex full

This should take care of the problem.

HTH,Please rate if it does.

-amit singh