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New Member

Problems Interconnecting 2960s switches


I have to be honest - I probably have no business attempting to configuring these switches but I am forced into it.

We have configured 2 x 2960s switches and connected them together between floors via a fibre cable.

This fibre connection is setup for trunking. On one of the floors I need to connect to a set of 3650 switches.

The idea is to create 3 vlans on each switch, assign ports on each switch to the vlans and have the vlan traffic go between floors.

Seems to work when I connect a device to a port on either switch.

The problem I am having is that there are another set of switches - with multiple vlans (including the 3 that I am trying to connect between floors) that I want to connect to. These other switches are controlled by another group and I do not have access to them. When I plug either a CAT 6 cable or x-over cable between the 2960s and the other groups switches (these are 3650's) the link light for the port comes on for about a second or two and then goes off. I know I am missing something here but have no ide how to get the links between vlans on the 2 set's of switches to connect (the link light to stay on). I have connected cables for all 3 vlans between the switches - all show the same sysmtoms.

Any assistance or idea's would be appreciated.

Thanks in advance,


Everyone's tags (2)

Problems Interconnecting 2960s switches

It sounds like the port that you're connecting to is shutting down either due to port security or bpduguard. Can you get in touch with the group that controls the 3560s and ask what they're seeing?


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HTH, John *** Please rate all useful posts ***
New Member

Problems Interconnecting 2960s switches


I will try to get in touch with this group. I was trying to avoid that since they take weeks to respond to any request.

In the meantime I will check the switch logs to see if there is any helpful information in them.

New Member

Problems Interconnecting 2960s switches

How do I rate a post? Clicked on the stars and lights them up but still says 0 ratings.

Problems Interconnecting 2960s switches

I could be reading this wrong but it sounds like you have connected your 2960 switches together and then connected each of them to another switch (or switches)?

If so, spanning tree is likely putting the ports into a blocking state as its detected a loop.

Can you draw up a rough sketch of the topology?

New Member

Re: Problems Interconnecting 2960s switches


Not quite. The basement switch is connected by fibre to the upstairs switch using Fibre.

Only servers and workstations connect to the basement switch. The upstairs switch has only four connections - one for each VLAN that are connected to the original switch.