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New Member

Switch trunk is not working

Dear expert need your assistance.

I have two cisco WS-C2940-8TF-S switches, 8 port switch 1 is connected to Server switch and switch 2 is connecting to 8 port switch 1.

switch 2--->Switch 1--->Server SW-->Core.


When connecting switch 2 to switch 1 the ports is not coming up, ports are configured as trunk.

not seeing any LED blinking too, basically status of port is notconnected.

I connect the switch 2 to directly Sarver switch it workes but not working when connect to switch 2.

Distance between Switch2 and switch 1 is 250ft, and hope its acceptable 

Appreciate your responses and help. 

Hall of Fame Super Gold

You need to test the length

You need to test the length of the cable.  


Here's the easiest way to test. 


Remove the configuration of two ports.  Disable STP portfast.  Connect the cable to two ports.  If the ports light up, you've got a good cable.  If they don't, your cable is faulty.

New Member

thanks Leo for your response.

thanks Leo for your response..


We have tested the same cable connecting to the server switch it works... only we are facing issue when connect to switch 1.


Any output would be appreciated.

Hall of Fame Super Gold

Ok.  This is from a 2940 to a

Ok.  This is from a 2940 to a what? 

You need to have a cross-over cable.

New Member

Hey Leo,Looking at the

Hey Leo,

Looking at the original post looks like hes running 2 Cisco WS-C2940-8TF-S Switches.

I am assuming that the readout from the SW1&SW2#show ip int brief command shows both line status and protocols as down.

That to me would scream cable, so they are probably using a straight through instead of crossover.


New Member

Dear, Leo/Michael, Appreciate

Dear, Leo/Michael,
Appreciate your suggestions and support.
Apologies, missed to mention this site is managed remotely.
Suspecting, Local support guy using straight through instead cross over. I will verify cable with Local guy and make sure to use the cross over cable.
thanks you very very much for you kind support.


New Member

Hi ateeqs,250ft is ok for

Hi ateeqs,

250ft is ok for Cat5 cable, maximum run length is 100 meters or 325ft approx.

Following on from Leos post below.

I would suggest the following, if both switches are accessible to you, take off all trunking config from the ports and hook up a laptop, make sure there's no issue with ether of the ports.

Next thing to check is the actual cable your using, is it a straight through or cross over, if its a straight through then you need to make sure that auto sensing is working on both ports else they will be receiving and transmitting on the same wires.

If there are patch panels between the link try using different patch ports.

Finally double check your trunking configuration and encapsulation.

Could be helpful to see the config you have on both switches if you can post that up.


New Member

You are using the wrong media

You are using the wrong media!


You have two choices:


1) Use a cross-over cable.

2) Enable 'auto-mdix' on the interfaces, along with the speed and duplex mode, the former is normally enabled by default, but a quick look on your behalf reveals you have to enable this on the 2940 (this is not a model I am conversant with, so maybe it's old?)



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