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- Different flavours of VPN: technology and applications
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- Different flavours of VPN: technology and applications
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- Appendix 1: VPN-enabling technologies
- Appendix 2: Table of VPN-enabling technologies
Different flavours of VPN: technology and applications

Victor Olifer
With contributions from Duncan Rogerson, Steve Williams, Rina Samani, David Salmon, Chris Cooper, Andrew Cormack
Virtual Private Networks, or VPN, provide a customised enterprise IP network service among several sites, belonging either to the same organisation or to collaborating organisations, over an IP network such as the Internet or JANET. The generic term ‘VPN’ currently covers different kinds of services which can benefit different kinds of applications through improved security and/or performance in the way they transport traffic. This document briefs network managers on Janet’s current position as regards VPN, the different flavours of VPN available, and the current position of VPN on other networks around the globe. The Appendix is a technical supplement that provides background information about VPN-enabling technologies.
For background reading see Virtual Private Networks, Second Edition by Charlie Scott, Paul Wolf and Mike Erwin. 1999, O’Reilly & Associates.