From The Editor - The Internet Protocol Journal - Volume 1, No. 2

We begin this issue with Part II of ?What Is a VPN?? by Paul Ferguson and Geoff Huston. In Part I they introduced a definition of the term ?Vir-tual Private Network? (VPN) and discussed the motivations behind the adoption of such networks. They outlined a framework for describing the various forms of VPNs, and examined numerous network-layer VPN structures, in particular, that of controlled route leakage and tunneling. In Part II the authors conclude their examination of VPNs by describing vir-tual private dial networks and network-layer encryption. They also examine link-layer VPNs, switching and encryption techniques, and issues concerning Quality of Service and non-IP VPNs.

IP Multicast is an emerging set of technologies and standards that allow many-to-many transmissions such as conferencing, or one-to-many transmissions such as live broadcasts of audio and video over the Internet. Kenneth Miller describes multicast in general, and reliable multicast protocols and applications in particular. Although multicast applications are primarily used in the research community today, this situation is likely to change as the demand for Internet multimedia applications increases and multicast technologies improve.

Successful deployment of networking technologies requires an under-standing of a number of technology options ranging from wiring and transmissions systems via switches, routers, bridges and other pure net-working components, to networked applications and services. The Internet Protocol Journal (IPJ) is designed to look at all aspects of these ?building blocks.? This time, Thayumanavan Sridhar details some of the issues in the evolution of Layer 2 and Layer 3 switches.

Interest in the first issue of IPJ has exceeded our expectations, and hard copies are almost gone. However, you can still view and print the issue in PDF format on our Web site at The current edition is also available on the Web. If you want to receive our next issue, please complete and return the enclosed card.

We welcome your comments, questions and suggestions regarding any-thing you read in this journal. We are also actively seeking authors for new articles. The Call for Papers and Author Guidelines can be found on our Web page. Please send your comments to

Ole J. Jacobsen, Editor and Publisher