IPv6 Essentials, 3rd Edition

Chapter 7. Transition Technologies

This chapter provides an overview of the various transition mechanisms that are available. IPv6 and IPv4 will coexist for many years, and there are a wide range of techniques that make coexistence possible and provide an easy transition. It is important to make the right choices and find the best migration path. There is not an easy one-size-fits-all strategy. The migration path has to be adjusted to the individual requirements of each organization and network.

The available techniques that support you in your transition are separated into three main categories:

Dual-stack techniques

Allow IPv4 and IPv6 to coexist in the same devices and networks

Tunneling techniques

Allow the transport of IPv6 traffic over the existing IPv4 infrastructure

Translation techniques

Allow IPv6-only nodes to communicate with IPv4-only nodes

These techniques can and likely will be used in combination with one another. The migration to IPv6 can be done step-by-step, starting with single hosts or subnets. You can migrate your corporate network or parts of it while your ISP still runs only IPv4, or your ISP can upgrade to IPv6 while your corporate network still runs IPv4. This first section describes the techniques available today for each of these categories. RFC 4213, “Basic Transition Mechanisms for IPv6 Hosts and Routers,” describes the dual-stack technique and configured tunneling. There has been a lot of change in this area; transition mechanisms that were key ...