[c-nsp] Preventing IS-IS adjacencies over 1Q trunk

[Justin Shore]

Phil Bedard wrote:
> For cleanliness I would not use the native vlan, use a separate vlan for 
> the interconnect.
> To answer the actual question, just set the interfaces as passive in the 
> ISIS configuration and they will be advertised but will
> not form adjacencies.


Thanks for the reply.  Just to be clear, are you suggesting I have a 
physical link (or Etherchannel) for the L3 peering between the chassis 
and another link (or Etherchannel) to carry L2 VLANs?  Or are you just 
saying to not use the native VLAN for the L3 and to just carry another 
tagged VLAN across for the L3 relationship?

I ran into a problem last week when I tried to restrict the allowed 
VLANs on the Etherchannel.  The IOS would let me restrict them but 
wouldn't let me remove the allowed VLAN list and set it back to 
implicitly allowing all VLANs (or switchport trunk allowed vlans all). 
It kept throwing up a crypto error about SVIs with crypto maps on them. 
  In the end I had to remove the Etherchanel, clean up the member port 
configs and re-create the Etherchannel.  I'm a bit leary about messing 
around with the VLANs between the chassis until I can figure out what 
exactly caused the IOS to freak out.

Thanks for the info
  Justin