Layer 2 VPNs

In an effort to provide secure connections through the public networks, service providers developed their own proprietary technologies or combinations of technologies. Some of these early VPN implementations were Layer 2 technologies, while others were Layer 3.

Using the broad definition of a VPN as “a private network built upon or within a public network,” public X.25, Frame Relay, and ATM networks’ use of virtual circuits within their public networks can be considered VPNs. The shared nature of these technologies allowed them to be less expensive than comparable dedicated circuits. These types of VPNs are generically referred to as Layer 2 VPNs. Unfortunately, these services don’t address universal access because they are unavailable in many parts of the country and world.