Features of L2TP are as follows:

• Flexible ID authentication mechanism and high security

  L2TP itself does not provide connection security, but it can depend on the authentication, such as CHAP and PAP, provided by PPP. Thereby, it has all security features of PPP.

  L2TP can integrate with IPSec to fulfill data security, which make it more difficult to attack the data transmitted with L2TP.

  To improve data security, based on the requirement of specific network security, L2TP adopts:

  • Tunnel encryption technique

  • End-to-end data encryption

  • Application layer data encryption

• Multi-protocol transmission

  L2TP transmits PPP data packet and a wide variety of protocols can be encapsulated in PPP data packet.

• Supporting authentication by RADIUS server

  LAC sends user name and password to the RADIUS server for authentication request. The RADIUS server is in charge of:

  • Receiving authentication request of the user

  • Fulfilling the authentication

• Supporting internal address assignment

  LNS can dynamically assign and manage the addresses of remote users and support the application of private addresses. The IP addresses assigned to remote users are internal private addresses of the enterprise instead of Internet addresses. Thus, the addresses can be easily managed and the security can also be improved.

• Reliability

  L2TP supports backup LNS. When active LNS is inaccessible, LAC can reconnect with the backup LNS, which improves the reliability and fault tolerance of VPN service.

Really useful protocol ...... good to know. thanks.