Most businesses extend their own networks for daily huge data, information, messages, news, etc among peers and boss. Sometimes, employees are not always sit in office, they may go anywhere for their business. VPN allows people to accomodate the needs of mobile employees and distant offices. It uses a public network (usually the Internet) to connect remote sites or users together. VPN uses "virtual" connections routed through the Internet from the company's private network to the remote site or employees.

In the markets, there are generally provided three types of networks for data transmission which are VPN, IPLC and general broadband service. VPN is a way of making a secure and stable private network via public Internet instead of using leased lines. Packets of data will be encapsulated by using specific protocols before send it through the Internet to a VPN user.

The main reason that companies use VPN is that they can transmit sensitive data & information over the Internet without needing to worry about who might get it. Everything that goes over a VPN is encrypted to such a level that even if someone captured a copy of the traffic, they could not read the traffic even if they used super computers worth million of dollars.

The process of encapsulation works through the Internet called tunneling. Tunneling is the process of placing packets of data together and sends it out to the others through the Internet networks. The protocol of the outer packet is called tunnel interfaces. Data goes through tunnels that is protected in safety.