What is a Virtual Private Network (VPN)? How does it work

A Virtual Private Network (VPN) permits the provisioning of private network services for an organization or organizations over a shared infrastructure. The VPN backbone is the shared service provider backbone network. It is used to transport traffic for multiple VPNs, as well as possibly non VPN traffic.

Over the past few years, IP and IP/Multi-Protocol Label Switching (MPLS)based VPNs have become increasingly popular. However, VPNs provisioned using technologies like Frame Relay and Asynchronous Transfer Mode (ATM) virtual circuits (VC), have been long available.

WAN –limitations

Till yesterday, reliable communication has meant the utilization of leased lines to maintain a wide area network. Leased lines, from Integrated Services Digital Services to Optical Carrier 3 fiber, provide a company with a manner to dilate their private network beyond their immediate physical area. When it comes to security, performance, reliability, a WAN has clear advantages over a public network. Maintaining a WAN is, however, expensive.

Intranets

As net popularity has grown, businesses have recourse to it to expand their own networks. It began with Intranets, followed by VPNs. The latter was supposed to connect far-flung employees to the office.

VPN defined

A generic VPN might have a main LAN at the corporate headquarters of a company, other LANs at remote facilities or offices, and individuals connecting from out in the field.

Also, a VPN is a private network that employs a public network to link remote sites or users. Rather than using a dedicated, real-world connection, for instance, a leased line, a VPN uses ‘virtual’ connections routed through the internet from the company’s private network to the remote employee or site.

Types of VPN

We have two types of VPN –

Remote Access – Also known as a Virtual Dial-up Network, this is a user to LAN connection used by a company with employees that need to connect to the private network from far-removed locations. Generally, a corporation that desires the setting up of a large remote access VPN provides some form of Internet dial-up account to their users using an Internet Service Provider. Subsequently, telecommuters can dial a 1-800 number to reach the Internet, using their VPN client software to access the corporate network. A great example of a company that requires a VPN to a company with an uncountable number of field salespeople. Remote-access VPNs permit encrypted, secure connections betwixt the company’s own network, and remote users through a third-party service provider.

Site to Site – By using dedicated equipment and large scale encryption, a company can connect multiple fixed sites over a public network. Each site only requires a local connection to the same public network. Thus they save money on long private leased lines. A site to Site VPNs may be, in turn, grouped into extranets or intranets. While a VPN built to connect the company to its partner or customer is called an extranet VPN. A site to site VPN built between offices of the same company is called an intranet VPN.

A well designed can this way impact a company positively

• Extend regional connectivity;
• Reduce operational costs;
• Decrease transit times;
• Increase productivity;
• Simplify network topology;
• Provide opportunities for global networking;
• Give telecommuter support;
• Greater ROI than WAN.

Features of a well-designed VPN network

• Security;
• Reliability;
• Scalability;
• Policy management;
• Network management.

VPN technologies

Above all, VPN utilizes various methods to keep connection and data secure

• Data confidentiality – Because your private data travels over a public network, data encryption ensures data confidentiality.
• Data Integrity – it is essential to check if the data has changed while in transit.