Layer 2 Tunneling Protocol (L2TP) Active Discovery Relay for PPP over Ethernet (PPPoE)

The Point-to-Point Protocol (PPP) provides a standard method for transporting multi-protocol datagrams over point-to-point links. Layer Two Tunneling Protocol (L2TP), facilitates the tunneling of PPP packets across an intervening packet-switched network. And yet a third protocol, PPP over Ethernet (PPPoE) describes how to build PPP sessions and to encapsulate PPP packets over Ethernet. L2TP Active Discovery Relay for PPPoE describes a method to relay Active Discovery and Service Selection functionality from PPPoE over the reliable control channel within L2TP. Two new L2TP control message types and associated PPPoE-specific Attribute Value Pairs (AVPs) for L2TP are defined. This relay mechanism provides enhanced integration of a specific feature in the PPPoE tunneling protocol with L2TP. This memo provides information for the Internet community.