Building an MPLS Network on top of L2VPN

[pavlosd]

Hi,

I was wondering, is it possible to build an MPLS network on top of L2VPNs? To be more specific, Imagine that a Service provider X can offer you point-to-point or point to multipoint Ethernet L2VPNs. You might want to take advandage of this in order to build your own MPLS network transparently (without the need to do carrier-to-carrier).

Is this senario possible?

[Harold Ritter · Accepted solution]

Pavlos,

I personally haven't seen anybody implementing MPLS over a L2VPN service but it is possible in principle to do so.

The issue I see is exactly the same as if you used regular Ethernet interfaces to implement MPLS, in which case you need to make sure that baby giant frames (slightly larger than 1500 bytes) are supported to handle the MPLS overhead.

This would have to be worked out with the L2VPN SP.

Let me know if I answered your question,

[pavlosd]

Good to hear.

Technically speaking, how will the PE router "treat" the mpls packet from the CE, just as a GIANT? Is the MPLS label on top of Etherenet label so will not care about other layers?

Thanks again.

[Harold Ritter · Accepted solution]

Pavlos,

The PE providing the L2VPN service indeed treats the incoming ethernet frame as a baby giant frame and does not care whether the next layer in the frame is MPLS or any other protocol.

It then takes the ethernet frame (minus the preamble and FCS), encapsulates it with a Martini header, imposes MPLS label(s) and forwards it to the egress PE.

Let me know if I answered your question,

[pavlosd]

Yeap. Thanks.

[vdcnetworks]

How did you get on with creating your network ???

just curious as i am building a similar network.

[romccallum]

Although this in principle will work no problems - why dont you consider CSC?

[Harold Ritter]

Good point. CsC would definitely be an alternative to run your own MPLS network through your SP network. This needs to be discussed with the SP, which might or might not support l3vpn services.

Hope this helps,