[c-nsp] Why it won't route vlan 1 ?

[Jared Mauch]

On Tue, May 15, 2007 at 05:52:21PM +0200, jcovini at free.fr wrote:
> Running 12.2.18SXF8 on sup720-3b/6506
> 
> Router(config)#int gi1/1
> Router(config-if)#no switchport
> Router(config-if)#int gi1/1.1
> Router(config-subif)#encapsulation isl 1
> Command rejected: VLAN 1 cannot be allocated because it is a default VLAN
> Router(config-subif)#encapsulation dot1Q 1 native
> Command rejected: VLAN 1 cannot be allocated because it is a default VLAN
> 
> However this was working like a charm on older IOS versions, or onto other
> platforms, so is it a platform limitation ? Is it due to 12.2.18SXF8 ? Should I
> consider a change towards SXD train ? I am heritating of this design and need to
> route all my .1 subinterfaces, without renumbering them if possible.

	There is only one 'vlan1'

	if you have vlan1 on more than one interface (eg: gig1/1 and gig1/2)
they are actually the same vlan.  This device is a switch, not an
independent router.

	You should be able to 'no shut' the vlan1 interface and use that
instead and leave the port as a trunk.  vlan1 has been generally 
'pseudo-reserved' on cisco for as long as I can remember.  I suspect
that it was working some other way was some odd artifact of the code that
they've since closed to prevent unexpected operation.

	- Jared

-- 
Jared Mauch  | pgp key available via finger from jared at puck.nether.net
clue++;      | http://puck.nether.net/~jared/  My statements are only mine.