1 - Introduction

Abstract

In 1995, Internet Protocol version 6 (IPv6) was picked as the final IPng proposal. The IPv6 base specification is specified in RFC 1883 and revised in RFC 2460. In a single sentence, IPv6 is a reengineering effort against IP technology. One of its key features is that it has a larger IP address space. IPv6 has simpler packet header structures than IPv4. It will allow vendors to implement hardware acceleration for IPv6 routers easier. IPv6 allows more flexible protocol extensions than IPv4 by introducing a protocol header chain. Even though IPv6 allows flexible protocol extensions, IPv6 does not impose overhead to intermediate routers. Today, most of the nodes on the Internet use IPv4. IPv6 is needed gradually introducing to the Internet and all nodes on the Internet are hopefully made IPv6-capable. To do this, the IETF has carefully designed IPv6 migration to be seamless. This is achieved by the following two key technologies: dual stack and tunneling. From a programmer's point of view, IPv4 and IPv6 are almost exactly the same. There is an IP address (size differs: 32 bit and 128 bit) to identify nodes (network interfaces) and a TCP/UDP port number to identify services on the node.