IPv4/IPv6 Co-Existence Technologies

This chapter highlights the myriad defined IPv4/IPv6 co-existence technologies and discusses the salient features and advantages of each to help you to decide where a given technology choice makes the most sense. From a general perspective, the set of IPv4/IPv6 co-existence technologies can be organized into three categories: dual stack - implementation of both IPv4 and IPv6 protocols on network devices; tunneling - encapsulation of an IPv6 packet within an IPv4 packet for transmission over an IPv4 network or vice-versa; translation - IP header, address, and/or port translation such as that performed by host, gateway or network address translation (NAT) devices. The chapter discusses the application support of IPv6. Finally it talks about some service providers' dual protocol strategies involving a combination of technologies from multiple categories.