Compared to Layer 3 MPLS, a Layer 2 VPN requires no peering with the provider edge (PE) routers and emulates a LAN segment, where, for instance, a HQ and branch router are connected on the same subnet. There are two options for this deployment.
- Point-to-Point Layer 2 MPLS VPN: Each connected pair of routers has a dedicated network, for instance, a /30. This has scalability concerns if the MPLS network grows significantly. This is especially true if you require inter-branch communications.
- Multi-Point Layer 2 MPLS VPN: All routers belong to the same network segment, and share a broadcast domain. All routers will peer with each other. Configuration of EIGRP authentication is highly encouraged for security purposes.
It is also possible to have a Metro-E (or local Layer 2 MPLS VPN switched network) where customer traffic via P2P links never transits the service provider core.
Stuck-in-Active: Journal of an IT-Network Administrator 