Virtual Private Network(VPN)
Virtual Private Network is a type of private network that uses public telecommunication, such as the Internet, instead of leased lines to communicate. The Internet is used as the backbone for VPNs. It saves cost tremendously from reduction of equipment and maintenance costs. VPN transmits data by means of tunnelling. Before a packet is transmitted, it is encapsulated (wrapped) in a new packet, with a new header. This header provides routing information so that it can traverse a shared or public network, before it reaches its tunnel endpoint. This logical path that the encapsulated packets travel through is called a tunnel. When each packet reaches the tunnel endpoint, it is “decapsulated” and forwarded to its final destination. Both tunnel endpoints need to support the same tunnelling protocol. The most commonly used tunnelling protocols are — IPSec(Tunnel Mode) — PPTP (Point-to-Point Tunnelling Protocol ) — L2TP(Layer 2 Tunnelling Protocol ) — SSL
