6.1 INTRODUCTION

When a node plugs in and wants to be a member of a network, information such as IP address and router information is needed for the configuration of that node. It can be configured manually or automatically with such information. In IPv4, manual configuration is common. This creates heavy burden on network administrators as well as users. However, IPv6 provides automatic address configuration feature to IPv6-enabled nodes, which allows assigning unique addresses and getting network information when they plug in. ^[1]

Autoconfiguration is composed of a sequence of processes which create a link-local address, verify and guarantee the uniqueness of assigned addresses, determine which information should automatically be configured, and decide whether stateless, stateful or both address configuration mechanism would be adopted. Each step issued above may be automatically performed in IPv6. Since autoconfiguration is one of major features of IPv6, it is hard to consider IPv6 and autoconfiguration separately.

This chapter explains how to build link-local and global addresses, and how to guarantee uniqueness on the address assignment. Both stateless and stateful address autoconfiguration are explained.

6.2 STATELESS AND STATEFUL AUTOCONFIGURATIONS

IPv6 defines two autoconfiguration mechanisms: stateless and stateful address autoconfigurations. When stateful autoconfiguration mechanism is employed for the address configuration, a specific server stores and manages whole address information for the managed domain. Thus, it is possible to manage address resources efficiently.

Almost no manual configuration on hosts is required...