Layer Two Tunnelling Protocol (L2TP) Over ATM Adaptation Layer 5 (AAL5)

The Layer Two Tunneling Protocol (L2TP) provides a standard method for transporting the link layer of the Point-to-Point Protocol (PPP) between a dial-up server and a Network Access Server, using a network connection in lieu of a physical point-to-point connection. This document describes the use of an Asynchronous Transfer Mode (ATM) network for the underlying network connection. ATM User-Network Interface (UNI) Signaling Specification Version 4.0 or Version 3.1 with ATM Adaptation Layer 5 (AAL5) are supported as interfaces to the ATM network.