[c-nsp] Combining multiple vlans into a single vlan.

[Peter Rathlev]

On Mon, 2008-12-08 at 20:40 -0500, Jeff Cartier wrote:
> Could this be accomplished using a ME3750, using BVI's? and if yes,
> any configuration examples?
>
> A co-worker said he tried this and couldn't make it work...

BVIs probably only work on "real routers". With the L3 switches you
would need a physical loop cable. (The BVI is the L3 interface by the
way, so just short circuiting the VLANs is just a "bridge-group".)

I'm not adequately familiar with the ME3750, but I guess it can't do
brige-groups. On a device that could, you would do something like this:

! *** On some router ***
bridge irb
!
interface GigabitEthernet0/0/1.630
 encapsulation dot1q 630
 bridge-group 5
!
interface GigabitEthernet0/0/1.631
 encapsulation dot1q 631
 bridge-group 5
!
interface BVI5
 description Optional, only when L3 termination is needed
 ip address 10.0.0.1 255.255.255.0
!
bridge 5 protocol ieee
!

Still, combining different VLANs this way could lead to lots of
problems, a.o. short circuiting spanning trees.

Regards,
Peter