Learning to spell VPN

Leaping from obscurity to popularity, virtual private networks have made their mark on telecommunications. The needs and reasons for using VPNs-to transport voice and data efficiently and securely using a packet approach-are clear. But the definitions of the various flavors are not.

In today's terms, VPN usually refers specifically to a network based on Internet protocol. But, even within that category, there are several variations. With many vendors and end users struggling with these issues, the VPN market probably won't take off as quickly as it would if all these issues were settled.

According to a recent study by Infonetics Research, worldwide expenditures by enterprises for VPN services could be as high as $10 billion in 2001 and could hit more than $29 billion in 2003. How can industry players make sure these forecasts come true?

Many are suggesting standardizing VPNs, which would distinctly define each type. In March, Ascend Communications, Lucent Technologies, Shasta Networks and Telia Finland submitted a VPN framework to the Internet Engineering Task Force (Telephony, April 5, page 42). The submitted framework covers the vast range of VPN mechanisms and deployment scenarios, which the writers of the framework say prevents VPNs from being interoperable. But despite the submission of the framework, many vendors feel more needs to be done.

"All vendors should understand the need for a standard [vendor forum]," said David Ginsburg, director of consulting engineering for Shasta. "We are not pushing as much for a timeline and an end-state, it is more the understanding and coming to agreement on what are the preferred approaches-if you can consider that a standard, maybe it is. The IETF isn't really taking the initiative to standardize VPN architectures," said Ginsburg.

"With so many definitions and so many different vendors deploying VPNs, there are a lot of different points of view and agendas," said Michael Howard, principal analyst for Infonetics. "This causes confusion to the end users or the people who are actually going to spend the dollars. It has and is having an affect on the VPN marketplace."

It is unfortunate that the industry currently does not have a name for every different type of VPN-but that is going to come, he said. "Right now, when we are conversing about VPNs, we need make clear what type of VPN we are talking about. You hear vendors say, 'I know you all have heard the definition of what a VPN is, and now here is ours.'"

The discrepancies among definitions will take some time to sort out, Howard said. He also noted that with no special sub-categories of VPNs that the industry agrees on, the problem worsens. While most people do agree that a VPN consists of services being provided over a public, shared network, others hold a more restrictive view that VPNs use tunneling and must be encrypted.

Vendors VPNet, Redcreek and Timestep believe VPNs use a tunneling technology such as IP Security, which is standardized.

"A lot of vendors producing VPN gateway products say VPNs must have tunneling, management and quality of service. Then you have companies offering service provider equipment or other services like Ascend, which has a multi-VPN strategy. They define three different kinds of VPNs," said Howard. Ascend's classifications include the virtual private remote network, virtual private trunking and virtual IP routing.

Ascend's strategy is, "It doesn't matter what kind of VPN you want, we have it all," Howard said.

"Some vendors have a software-only solution, which colors their view," said Rick Kagen, vice president of marketing for VPNet. "Some may make routers, so they think everything begins and ends with a router.

According to Howard, the formalization of all the definitions will come through the framework committee. But "certain vendors may not want standardization to occur, [which can hold things up]," he added.