What are the Tunneling Protocols of Virtual Private Network?

[Mei-Xiu]

I have recently started learning about the Virtual Private Network, so I am not aware about the basic things and the concepts of the VPN. I have given an assignment to write an information about the Tunneling Protocols that are used in VPN. I thought that you guys explain very neatly, so posting here would be helpful. Please tell me what are the Tunneling Protocols of Virtual Private Network? Also I am newbie to VPN, please provide some concept of virtual private network. I am hoping for some helpful and brief discussions about this topic.

[Milton.J]

I would like to discuss about the concepts of VPN. The local area network (LAN) networks are internal to an association that is to articulate that the connections between machines belong to the organization. These networks are gradually more connected to the Internet by means of interconnection equipment. It happens so often that companies feel the requirement to communicate with associates, customers or even staff geologically remote via the Internet. However, data transmitted over the Internet are much more susceptible than when running on an internal network in an organization, because the path that is not defined in advance, which means that the data are taking a public network communications owned different operators. Thus it is not unfeasible that the road traveled, the network is heard by a user indiscreet or even distracted. It is not plausible to transmit such susceptible information requirements for the organization or company.

[Snake08]

A virtual private network supported on a protocol called tunneling protocol, that is to say a protocol that permits data from one end of the VPN to be protected by other algorithms cryptography. The term "tunnel" is used to represent the fact that flanked by the entry and exit from the VPN data is encrypted (scrambled) and therefore unfathomable to anyone between the two ends of the VPN, as if the data passed in a tunnel. In the case of a VPN established between two machines, called VPN client element used to encrypt and decrypt data on the user side (client) and the VPN server (or more usually remote access servers) element encrypting and decrypting the data side of the association.

[Big Fish]

The major tunneling protocols are:

• PPTP (Point-to-Point Tunneling Protocol) is a protocol level 2 developed by Microsoft, 3Com, Ascend, U.S. Robotics and ECI Telematics.
• L2F (Layer Two Forwarding) is a protocol level 2 developed by Cisco, Northern Telecom and Shiva. It is now almost obsolete.
• L2TP (Layer Two Tunneling Protocol) is the culmination of the work of the IETF (RFC 2661) to converge the functionality of PPTP and L2F. It is thus a protocol level 2 based on PPP.
• IPSec is a protocol for Level 3, based on the work of the IETF, to carry data encrypted for IP networks.

[Shen]

• PPTP - The principle of PPTP (Point To Point Tunneling Protocol) is to create frames under the PPP protocol and encapsulating them in an IP datagram. Thus, in this connection mode, the remote computers on both LANs are connected via a connection point to point (including a system of encryption and authentication, and passes the packet in a IP datagram.
  
• L2TP - L2TP is a standard protocol for tunneling (standardized in RFC ) closely PPTP. Thus L2TP encapsulates frames PPP , wrapping themselves in other protocols (such as IP, IPX or NetBIOS).

[Steve123]

I think that knowing about the IPSec is also important since it is considered as an important factor of VPN. IPSec is a protocol defined by the IETF to secure the exchange at the network layer. It is actually a protocol providing improvements in safety at the IP protocol to ensure the confidentiality, integrity and authentication of trade. IPSec is based on three modules:

1. IP Authentication Header (AH) for integrity, authentication and protection against replay. Encapsulate packets
2. Encapsulating Security Payload (ESP) defining packet encryption. ESP provides confidentiality, integrity, authentication and protection against replay.
3. Security Associate (SA) defines the exchange of keys and security settings. SAs and gather all information on the treatment to be applied to IP packets (protocols AH and / or ESP, transport or tunnel mode, the algorithm used by security protocols, the keys used ,...). The key exchange is done either manually or with the exchange protocol IKE (mostly), which allows both sides of heard on the SA.

[Spyrus]

The term "tunnel" is used to represent the fact that flanked by the entry and exit from the VPN data is encrypted (scrambled) and therefore unfathomable to anyone between the two ends of the VPN, as if the data passed in a tunnel. In the case of a VPN established between two machines, called VPN client element used to encrypt and decrypt data on the user side (client) and the VPN server (or more usually remote access servers) element encrypting and decrypting the data side of the association.

That way, when a user desires to contact the VPN, the request will be broadcasted unencrypted system gateway that will attach to the remote network via a public network communications, and will transmit the application in figures. The remote computer will then supply the data to the VPN server's local network that will broadcast the response in figures. A response on the VPN client user, the data will be decrypted and then sent to the user.

[ms123]

Yes, a nice explanation about what is tunneling protocol & how it can be useful has been provided here in allowing the users access to world of Virtual Private Network Services.