What is VPN

VPN is English "virtual private network" abbreviation, namely "Fictitious private network".

Virtual Private network is based on the real network (or physical network) on the basis of a functional network, or to say that is a private network of the network mode, referred to as VPN. It provides the user with the function of the general private network, but it is not a separate physical network, it can also be said that the virtual private network is a kind of logical network. "Virtual" indicates that it is different from the physical network in composition, but for the user, the function is identical to the real private network.

The current virtual private network can be divided into three categories:

(1) on the telephone network to provide users with switched-connected circuit business, can be used to call or transmit traffic data;

(2) The service of connecting type virtual circuit (switched virtual circuit or permanent virtual circuit) which is implemented on the Packet Exchange data network can be used to transmit packet data service;

(3) on the digital data network, to the user to provide fixed or semi-permanent (permanent or semi-permanent) connection-type circuit business, can be used to transfer data between point-to-point, voice and image services.