Secondary dot1q tag? - Carry multiple VLANs in just one VLAN?

[craig.cartlidge1]

Hi,

First of all apologies as I am a bit of a newbie but I have a question that I hope some folks on this could possibly shed some light on / lead me down the correct path.

I work in an enterprise campus / branch office style setup. all remote sites are connected over the providers WAN infrastructure (a multipoint l2 cloud), the provider will only carry traffic with an 802.1q tag of 400.

I want to use VRF lite between a number of sites to create a totally isolated segment, however I don't see how I can multiplex an additional VLAN onto the WAN to provide the segregation when the provider will only carry vlan 400.

Im using cisco 4321/1921 ISR's at the branch sites and have been looking into q-in-q but Im not sure as to how I should configure it / is this even possible?

Any ideas?

Thanks in advance :)

[Joseph W. Doherty]

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Posting

Off the top of my head, cannot comment on 4321/1921 configurations for Q-in-Q, but generally what you're describing is how you use Q-in-Q, i.e. pass your VLANs across a provider's VLAN tagged infrastructure.

You should confirm, you provider won't have any issues.

I've only used Q-in-Q once, years ago, and in that case, my edge device was (?) a switch.  I also recall, it was very simple to configure.