The world has changed a lot in the
last couple of decades. Instead of simply dealing with local or regional
concerns, many businesses now have to think about global markets and logistics.
Many companies have facilities spread out across the country or around the
world, and there is one thing that all of them need: A way to maintain fast,
secure and reliable communications wherever their offices are.
Until fairly recently, this has meant the use of leased lines to maintain a
wide area network (WAN). Leased lines, ranging from ISDN (integrated services
digital network, 128 Kbps) to OC3 (Optical Carrier-3, 155 Mbps) fibre, provided
a company with a way to expand its private network beyond its immediate
geographic area. A WAN had obvious advantages over a public network like the
Internet when it came to reliability, performance and security. But maintaining
a WAN, particularly when using leased lines, can become quite expensive and
often rises in cost as the distance between the offices increases.
As the popularity of the Internet grew, businesses turned to it as a means of
extending their own networks. First came intranets, which are
password-protected sites designed for use only by company employees. Now, many
companies are creating their own VPN (virtual private network) to accommodate
the needs of remote employees and distant offices.
Basically, a VPN is a private network that uses a public network (usually the
Internet) to connect remote sites or users together. Instead of using a
dedicated, real-world connection such as leased line, a VPN uses "virtual"
connections routed through the Internet from the company's private network to
the remote site or employee. In this article, you will gain a fundamental
understanding of VPN's, and learn about basic VPN components, technologies,
tunnelling and security.
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