Shulou(Shulou.com)06/01 Report--

Virtual tunneling protocol tunneling technology is a technology to encrypt data communication between private networks or private devices through the infrastructure of the public network. The content of the communication can be a packet of any communication protocol. The tunneling protocol re-encapsulates the packets of these protocols and sends them in new packets. The new packet header provides routing information so that the encapsulated data can be transmitted through the public network, and the logical path is called a tunnel. When the packet reaches the end of the communication, it will be unsealed and forwarded to the final destination. Tunneling technology refers to the whole process including data encapsulation, transmission and data unpacking.

The second layer corresponds to the data link (Data-Link) layer and exchanges data with frame (frame) as a unit. PPTP, L2TP and Layer2Forwarding (L2F) are layer 2 tunneling protocols. These protocols encapsulate the load in a Point-to-Point Communication Protocol (PPP) frame, encapsulate it in a tunneling protocol, and then transmit it over the network. Because layer 2 tunneling protocol is based on PPP communication protocol, it inherits some useful functions, such as user authentication, dynamic address assignment, data compression, data encryption and so on. If combined with ExtensibleAuthenticationProtocol (EAP), it can support a variety of advanced user authentication methods, such as one-time passwords and smart cards.

The third layer corresponds to the network (Network) layer and takes the data packet (packet) as the data exchange unit. IP-over-IP and IPSec tunneling modes are examples of layer 3 tunneling protocols, which process IP packets (such as compression, encryption), encapsulate additional IP headers, and then transmit them over the IP network.

For layer 2 tunneling technology, the tunnel is like a session. The two endpoints of the tunnel must agree to the establishment of the tunnel and negotiate settings between the two, such as address assignment or encryption, compression parameters, and so on. The tunnel must have a process of establishment, maintenance, and then termination.

Layer 3 tunneling technology usually assumes that all setup issues are not negotiated during the communication process, but are dealt with manually in advance. For these protocols, there may be no tunnel maintenance phase.

As soon as the tunnel is established, you can begin to transmit data. The client or server of the tunnel will use the tunnel transfer protocol to prepare the data to be transmitted. When the data reaches the other end, the header of the tunnel transfer protocol will be removed and the data will be transferred to the target network.

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.