In reality, VPNs provide just a few basic, easy to understand, potential advantages over more traditional forms of wide-area networking. These advantages can be quite significant, but they do not come for free. The potential problems with VPNs outnumber the advantages and are generally more difficult to understand. From security and performance concerns to coping with a wide range of sometimes incompatible vendor products, the decision of whether or not to use a VPN cannot be made without significant planning and preparation. Authentication allows VPN clients and servers to correctly establish the identity of people on the network.
Encryption allows potentially sensitive data to be hidden from the general public.
Unfortunately, immature VPN standards mean that some of these products remain incompatible with each other. The success of VPNs in the future depends mainly on industry dynamics. Most of the value in VPNs lies in the potential for businesses to save money. Should the cost of long-distance telephone calls and leased lines continue to drop, fewer companies may feel the need to switch to VPNs for remote access. Conversely, if VPN standards solidify and vendor products interoperate fully with other, the appeal of VPNs should increase.