What are the types of L2VPN

L2VPN intelligence is limited to the provider edge (PE) routers. Therefore, L2VPN is an edge technology—like MPLS VPN—that uses an MPLS backbone.

L2VPN are categorized as

1)      VPWS ( Virtual Private Wan Services)

-          VPWS also known as AToM  or Xconnects

-          AToM is the Cisco name for the Layer 2 transport service over an MPLS backbone

-          VPWS  are Point-to-Point

-          We can connect two distant sites that use different Layer 2 technologies, for example one site uses frame relay and the other uses ATM.

-          Distant sites that can use any of these technologies: Frame-Relay, PPP, Ethernet, ATM, that's why xconnects are also called Any Transport over MPLS (AToM).

2)    VPLS ( Virtual Private Lan Services)

-          VPLS can be Point-to-Point (linking only 2 sites) and can be Multipoint (linking multiple sites together)

-          VPLS can only link Ethernet sites.

What if the Core of the Service Provider is IP based only.How can we transport L2 frames across this infrastructure? L2TPv3 is the Layer 2 transport service over an IP network. The Layer 2 frames are encapsulated with an L2TPv3 header and are transported across the IP network. Similar to AToM, L2TPv3 can carry ATM, Frame Relay, HDLC, PPP, Ethernet, ATM, and others.