[c-nsp] Problem with NPE-G1

[Justin M. Streiner]

On Sat, 7 Jan 2006, Robert Hass wrote:

> On Sat, 07 Jan 2006, Justin M. Streiner wrote:
>
>> On the switch:
>> int gig0/1
>> switchport trunk native vlan 200
>> switchport trunk allowed vlan add 200
>>
>> Do not add the "native" tag to any other VLANs you add to this trunk.
>>
>> Let me know if that works.
>
> Hm... by default native VLAN should be VLAN1, and by default dot1q VLAN1
> on routers at always placed at main interface - Gi0/1 at this case.

Wint some exceptions, Cisco doesn't force the native VLAN to be 1.  If you 
want to use VLAN 1 as the native VLAN, that's fine.  It's a good idea to 
set your native VLAN explicitly, rather than relying on assumed defaults.

on the 7200:
int gig0/1.1
  encaps dot1q 1 native
  no ip address (or put an IP address here if you want to manage the switch 
remotely)

on the switch:
int gig0/1
  switchport trunk native vlan 1
  switchport trunk allowed vlan add 1

int VLAN1
  ip address x.x.x.x y.y.y.y

Don't forget to set your default gateway accordingly.

> The problem (interface down , interface up) is also when I create any
> subinterface, so:
>
> conf t
>  int giga0/1.400
>  int giga0/1.401
>
> will do 2 interface flaps on the switch. I'm not using native vlan...
> and I want to leave native vlan on main interface.

Did you do any dot1q debugging on either side?

Does the interface come up/up on both sides if you make the link a routed 
interface/access port rather than a trunk?

jms