L2TP

L2TP is the short of Layer Two Tunneling Protocol. In fact it is the extension to the PPP protocol which allows the ISPs to operate VPNs (Virtual Private Networks. L2TP blends the superb properties of two other tunneling protocols. L2F from Cisco Systems and PPTP from Microsoft Corporation.  Like PPTP, the L2TP protocol also requires that routers of the ISP’s must support this very protocol.