VPN Types Based on OSI Model Layer
VPNs can also be classified based on the OSI model layer at which they are constructed. This is an important distinction to make. For example, in the case of encrypted VPNs, the layer at which encryption occurs can determine how much traffic gets encrypted, as well as the level of transparency for the VPN's end users.
Based on the OSI model layers, VPNs can be divided into the following three main categories:
Data link layer VPNs
Network layer VPNs
Application layer VPNs
Data Link Layer VPNs
With data link layer VPNs, two private networks are connected on Layer 2 of the OSI model using a protocol such as Frame Relay or ATM. Although these mechanisms provide a suitable way of creating VPNs, they are often expensive, ...
