[c-nsp] Multiple 802.1q subinterfaces with the same vlan under thesame physical interface

[luismi]

What I was thinking in assign different subinterfaces (from different
physical interfaces) to the same vlan in the same chassis.

I think that the router will be able to manage that configuration, for
example: fa0/0.1 and fa1/0.1 working in different vrfs but in the same
vlan, with different IP address from the same subnet.

Is that correct?

El mié, 02-07-2008 a las 08:22 +0200, Oliver Boehmer (oboehmer)
escribió:
> luismi <> wrote on Monday, June 30, 2008 8:15 PM:
> 
> > Hi there,
> > 
> > I have a dude I could solve using a lab enviroment but for several
> > reasons I don't have enought time at this momment, neither I have the
> > correct equipment here.
> > 
> > I am thinking on collapse several routers configurations in new
> > equipment, deploying subinterfaces with 802.1q and VRFs.
> > 
> > The situation is that for the same physical interface I would have
> > several subinterfaces, working in the same vlan but diferent vrf, with
> > also diferent ip addresses but all of them are in the same subnet.
> > 
> > The question is, is the router going to be enough clever to deliver
> > the packet in the correct interface? Take note that the IP address
> > use as destination in the incoming packet is not going to be ip
> > address of the interface since the router and its vrfs.
> 
> This is not going to work. The router needs the vlan tag to associate
> the appropriate (sub)interface with the packet, so the vlan tag has to
> be unique on the interface (some platforms like the 6500 even ask for a
> unique tag per system). VRF association comes later and is based on the
> vrf configured on the (sub)interface.
> So if you want to consolidate multiple vlan/.1q connections, you will
> need to change vlan IDs in order to make them unique. 
> 
> 	oli