What is Layer 2 Tunneling Protocol (L2TP)?


Written by: Per-Erik Eriksson

Tunneling Protocols are the layers of protocols that are created to communicate over networks that are inaccessible. These systems are used to get around firewalls, which block access to various types of websites. The point-to-point tunneling protocol (PPTP) is a type of tunneling protocol that can support different technologies by allowing users to create virtual links to remote data.

L2TP is the second level of tunneling protocol, which has been designed for transmitting data packets through a virtual tunnel on top of the IP network layer. SSH (Secure Shell) is another type of tunneling protocol that provides security for data connections, especially in Unix-based systems.

Layer Two Tunneling Protocol (L2TP) – Explained

Layer 2 Tunneling Protocol (L2TP) is a tunneling protocol for transmitting data packets through virtual tunnels on top of the IP network layer. These virtual tunnels are created by the L2TP control messages that encapsulate higher-level protocols, such as PPP.

L2TP was developed by Cisco Systems and Microsoft Corporation in 1994, and it has been used since 1996 with IPsec to secure point-to-point connections.

How L2TP Tunnels are Created?

L2TP tunnels can be created by software that uses the L2TP network device drivers. The Microsoft Windows operating system supports L2TP connections natively and includes support for both IPsec and PPTP tunneling protocols.

Third-party software is also available to allow other operating systems to support L2TP devices and tunnels. Cisco IOS also includes L2TP client and server functionality as part of its Border Gateway Protocol (BGP) implementation.

Where L2TP is used?

L2TP has been used with IPsec to secure point-to-point connections. In addition to passing through firewalls, the L2TP tunnel can be used as a mechanism to connect geographically separated offices of an organization, creating a wide area network (WAN).

It does this by forwarding data packets from the end-user across the Internet, through the carrier’s network, and to a remote access server at a corporate or other target site. From there, a person inside the organization can access the resources of its LAN as if they were on a local area network (LAN).

The Layer 2 Tunneling Protocol is described in RFC 2661 in the IETF RFC Database.

L2TP vs PPTP: Difference

The most important difference between Layer 2 Tunneling Protocol (L2TP) and Point-to-Point Tunneling Protocol (PPTP) is that PPTP is a protocol with a maximum transmission unit of a single packet at the IP level. L2TP, on the other hand, can transport any type of protocol. It can also be used for creating virtual private networks across the internet.

Layer 2 Tunneling Protocol (L2TP) is a technology for tunneling Point-to-Point Protocol (PPP) over an IP network. L2TP does not provide any encryption or confidentiality by itself. It relies on the protocol being tunneled to provide encryption/decryption of the data packets.

Advantage of L2TP

L2TP is a superior protocol to PPP as it provides a much higher level of security by way of IPsec. It supports a variety of tunneling protocols that can carry different types of traffic, such as IHDLC, HDLC, and LAPB. This way, the communication over the wireless links could be encrypted with an encryption layer as well as carried as a frame.

Bottom Line

If you’re looking for a tunneling protocol that is secure, reliable, and fast-working, Layer 2 Tunneling Protocol (L2TP) may be the best choice. The beauty of this protocol is its versatility; it can work over both IPv4 and IPv6 networks without any modifications to existing software setups. It also provides strong security because it uses encryption keys when transmitting data between two nodes connected via an extension link such as a DSL or cable modem.

This means that only these two systems know what’s being transmitted. It also works well with broadband, wireless and point-to-point setups.

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