About Layer 2 Connections
Layer 2 Tunneling Protocol (L2TP) is a network protocol used to create Virtual Private Networks (VPN), usually between an operator backhaul (deconsolidator ADSL or telephone operator) and the ISPs.
In computer networks, the data link layer is the second of the seven layers of the OSI (Open Systems Interconnection).
This protocol can transport connections retaining information from level 2 to level 7. The transport of these connections is through IP tunnels. The same tunnel can carry multiple connections, usually there is only one tunnel between the same two pieces of terminating equipment.