Layer 2 Tunneling Protocol (L2TP)

L2TP is an emerging IETF standard and one of the key building blocks for VPNs in the dial access space. L2TP combines the best features of Cisco’s Layer 2 Forwarding (L2F) and Microsoft’s Point-to-Point Tunneling Protocol (PPTP), enabling mobile workforces to connect to their corporate intranets or extranets wherever and whenever they require.

L2TP is a standard way to build Access VPNs that simulate private networks using a shared infrastructure, such as the Internet. These Access VPNs offer access for mobile users, telecommuters, and small offices through dial, ISDN, xDSL, and cable.

Benefits of L2TP include per-user authentication, dynamic address allocation from an address pool or by using DHCP server, plus RADIUS and AAA support.