Layer 2 VPNs (L2VPN) can be used to provide site-to-site Layer 2 connectivity. As discussed in Chapter 1, “What Is a Virtual Private Network?” L2VPNs can be built using technologies and protocols such as the Layer Two Tunneling Protocol version 3 (L2TPv3, RFC3931) and Any Transport over MPLS (AToM) and can fall into three categories:
Virtual Private Wire Service (VPWS)—. This type of L2VPN provides point-to-point MAN or WAN transport for Layer 2 protocols and connections such as Ethernet, High-Level Data Link Control (HDLC), PPP, Frame Relay, and ATM.
Virtual Private LAN Service (VPLS)—. A VPLS provides multipoint Ethernet connectivity.
IP-only Private LAN Service (IPLS)—. This is a newer ...