IPv6 Essentials

Chapter 10. Interoperability

IPv6 and IPv4 will coexist for many years. A wide range of techniques has therefore been defined that make the coexistence possible and provide an easy transition. There are 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 a single host or subnet. 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 chapter describes the techniques available today for each category mentioned above. RFC 2893, “Transition Mechanisms for IPv6 Hosts and Routers,” describes the initial set of transition mechanisms. As IPv6 grows into our networks, new tools and mechanisms will be defined to further ease the transition.

Dual-Stack Techniques

A dual-stack node has complete support for both protocol versions. This type of node is often referred to as an IPv6/IPv4 node. In communication with an IPv6 node, such a node behaves like an IPv6-only node, and in communication with an IPv4 node, it behaves like an IPv4-only node. Implementations probably have a configuration switch to enable ...