By | April 30, 2019


The term L2TP is a protocol widely used in computer networking. This is known as the Layer 2 Tunneling Protocol. This protocol is generally used to support the use or generation of the Virtual Private Networks (VPNs). This protocol is known for the privacy it provides to the data of the user. It uses an encryption model which passes from the tunnel to provide this privacy factor. The protocol works on two protocols combinedly ie L2F (Layer 2 Forwarding) & PPP (Point-to-Point Protocol). Hence we can say that this protocol is very useful in the networking world. The Layer 2 Tunneling Protocol can also be started on the router which supports this protocol. Here we will discuss this term in detail. Thus the users must check the details of the protocol from here.

Tunneling models of Layer 2 Tunneling Protocol

The protocol uses mainly 4 types of tunneling protocols. Those tunneling models are listed below.

  • Voluntary Tunnel.
  • Compulsory Tunel-Incoming Call.
  • Compulsory Tunnel-remote dial.
  • multihop Connection

Packet Structure of protocol

The data packet in this protocol contains various parts. The details of the structure of the data packet are as follows.

0 to 15 Bits 16 to 31 Bits
Flags and Version Info Length (optional)
Tunnel ID Session ID
Ns (optional) Nr (optional)
Offset Size (optional) Offset Pad (optional)

Payload data

Details of Packet Exchange in Layer 2 Tunneling Protocol

As we know that this protocol is related to the data exchange through tunnels which provides privacy to the data. hence the packet exchange will take place between the client & server by making tunnels & sessions for each direction. The details of the packet exchange can be understood by the image very clearly.


If the users still have an issue in relation to this protocol then they can leave their questions in the comment section. We will try to resolve the problem of the user very soon.

Leave a Reply

Your email address will not be published. Required fields are marked *