L2TP is defined in RFC 2661,Layer Two Tunneling Protocol (L2TP).
L2TP facilitates the tunneling of PPP packets across an intervening network in a way that is as transparent as possible to both end users and applications. It employs access profiles for group and individual user access, and uses authentication to establish secure connections between the two ends of each tunnel. Multilink PPP functionality is also supported.
The L2TP services are supported on the following routers only:
For more information about configuring L2TP services, see Layer 2 Tunneling Protocol Services Configuration Guidelines.