(Layer 2Tunneling Protocol) An IETF protocol that lets remote users access the corporate network. The PPP protocol encapsulates IP packets from the user's devices to the ISP, and L2TP extends that session across the Internet. L2TP was derived from Microsoft's Point-to-Point Tunneling Protocol (PPTP) and Cisco's Layer 2 Forwarding (L2F) technology. See PPP, PPTP and L2F.L2TP/IPsecL2TP does not include encryption but is often used with IPsec in order to provide virtual private network (VPN) connections. See VPN and VPN protocols.
A tunneling protocol used for secure node-to-node communications by Internet service providers (ISPs) and other virtual private network (VPN) service providers in support of multiple, simultaneous tunnels in the network core. End users gain access to the service provider on an unencrypted basis, with the service provider assuming the responsibility for encryption at the edge of the packet network. L2TP is an extension to the Point-to-Point Protocol (PPP) that evolved from a combination of Microsoft's PPTP and Cisco's Layer 2 Forwarding (L2F) protocol. L2TP is described in IETF RFC 2661. See also encryption, ISP, PPP, PPTP, protocol, tunneling, and VPN.