Multiple trunk ports on 2960 ?

[scottdemeyer]

Can the 2960 have more than one trunk port?

I'm trying to configure 5 ports as trunk ports on one of my 2960 switches but only one seems to work. The other 4 ports get placed into VLAN 1, and cease to function no matter what the configuration says. VLAN 15 is the default vlan for our network.

The config command I'm trying to use is:

int range g 0/40 - 48

switchport mode trunk

switchport trunk native vlan 15

Maybe this is not possible with this switch model?

Thanks,

Scott

[ankbhasi]

Hi Scott,

It is very well possible with any switch model. When you say other ports goes into vlan 1, are they showing in the running config for vlan 1?

Can you check and post the output of the other 4 ports which does not form a trunk "sh interface gig0/4x switchport"

Also what is connected to those ports and is the other end device is also configured for trunk?

Regards,

Ankur

[scottdemeyer]

Hi Ankur, thanks for your reply. I attached running config and show int outputs.

Could the problems be due to use of unmanaged layer2 switch used to connect trunk ports from each building?

Basically , I have 2960's for wkstn access in each bldg, each 2960 has 1 802.1q trunk port. These trunk lines feed into a central layer 2 unmanaged switch. These central unmanaged switches feed into the 2960 I'm trying to get the trunk ports working on.

[glen.grant]

If the other switches are unmanaged then you cannot trunk to them . You need switches on the other end that are configurable to be able to trunk to them . It won't work with that unmanaged switch in the middle.

[ankbhasi]

Hi Friend,

Can you confirm to which device your port gi0/48 is connected? Also on all your ports other than gig0/48 you also have configured access vlan 11 which I believe is not required if you want it to only work as trunk ports.

Regards,

Ankur

[scottdemeyer]

Gig 0/48 is connected to the unmanaged L2 switch. The other trunk ports from different bldg are connected to the unmanaged L2 switch as well.

I attached a simplified diagram of our network. I suspect the unmanaged switches will have to go.