[nsp] VLAN settings on 2950s/2610s

[Ryan O'Connell]

At 09/05/2003 16:12, Security wrote:
>I spend several hours working with catalyst2950 switch and a Cisco2610
>router trying to configure VLAN trunking using 802.1q. I Discover that when
>one of the VLANs is the default (VLAN1) trunking is not working. Using
>other vlans e.g vlan2 and Vlan3 trunking is working perfectly. According to
>Cisco Documentation trunking should also work with VLAN1 as one of the
>VLANs.
>
>Can anyone advise? I am thinking of a bug on the software of the switch but
>your advice will be appreciated

Make sure you have Native (default) VLANs set properly both sides - 
switches have a default native VLAN and router don't. Anything in the 
native VLAN doesn't get tagged when being sent out, so the router will drop 
it when receiving it unless one subinterface has been marked "native".

 From memory, by default on the 2950 the default native VLAN is 1 so you 
need to make sure you use "encapsulation dot1q 1 native" on the 2610 for 
the appropriate subinterface. (This is from memory though, I may have it wrong)