Appendix A. VPLS and IPLS Layer 2 VPNs

Pseudowire technologies such as Layer Two Tunneling Protocol version 3 (L2TPv3) and Any Transport over MPLS (AToM) enable service providers to converge their existing legacy (ATM, Frame Relay, and leased line) and IP/Multiprotocol Label Switching (MPLS) networks; these technologies also enable them to offer point-to-point Ethernet services.

A Virtual Private LAN Service (VPLS) takes advantage of point-to-point pseudowire technologies to enable multipoint emulated Ethernet LAN services over a metropolitan-area network (MAN) or wide-area network (WAN). An IP-only Private LAN Service (IPLS) provides similar multipoint emulated Ethernet LAN service but for IP-only traffic.

This appendix discusses the operation of VPLS and IPLS.