VPN can work this way

VPN can work this way: • dial-up • part of a router-to-router The VPN tunnel is actually just a logical point-to-point connection with the authentication and encryption. The analogy is that an organization / company has offices in two different buildings. Well, for people / moving information from one office to another, either through: • sidewalk or public street • dig a hole under the ground (analogous to the VPN). Encapsulation process Long package wrapped in a new package. End of the destination address of the tunnel (tunnel endpoints) is placed in the destination address new package, called the encapsulation header. The final goal remains the packet header length is wrapped (encapsulated). On reaching the endpoint, the capsule is opened, and the old package delivered to their final destination. Encapsulation can be performed on different network layers. Layer 2 Tunneling VPNs most commonly used data link layer, for example: Point-to-Point Tunneling Protocol (PPTP) from Microsoft. Another example is the Layer 2 Forwarding (L2F) from Cisco that can work on ATM and Frame Relay networks. L2F is supported by Internetwork Operating System is supported by Cisco routers. The newest is a Layer 2 Tunneling Protocol (L2TP), which combines elements of PPTP and L2F. Layer 3 Tunneling Tunneling can also be made at the IP layer. So the IP packet is wrapped in an IP Security (IPSec) using also IKE (Internet Key Exchange). IPSec can be used in several ways: transport mode: IPSec encryption, but is made by the L2TP tunnel. Note that L2TP can also encapsulate IPX (Internetwork Packet Exchange) and the type of layer 3 packets other. tunneling mode: IPSec encryption and tunneling it.