Technology - IPv6 2 - Autoconfiguration, ICMPv6 & Neighbour Discovery

Synopsis

We discuss some of the new features of IPv6 which enable automatic configuration of computers and other devices, which eases the burden of network renumbering and provides mechanisms for small devices to automatically connect themselves to networks, especially radio networks. However, these techniques are not sufficient to reliably renumber an entire network, as would be required when using Provider Aggregatable addresses and changing to another ISP.

Table of Contents

• 1. Synopsis
• 2. Introduction
• 3. The lower 64 address bits
  • 3.1 EUI-64 bit assignment
    • 3.1.1 Ethernet MAC addresses
    • 3.1.2 Conversion to EUI-64 format
    • 3.1.3 Generating the global unicast address
    • 3.1.4 Random privacy enhanced addresses
    • 3.1.5 DHCPv6
    • 3.1.6 DHCPv6 for allocating subnets
• 4. Autoconfiguration
  • 4.1 Stateless autoconfiguration
    • 4.1.1 Link-local unicast IP address
    • 4.1.2 Router Advertisement
    • 4.1.3 Choosing a global unicast address
• 5. Renumbering when changing ISP
  • 5.1 Continuity during changeover period
  • 5.2 Automating changeover for large networks
  • 5.3 Practical limits to automated renumbering
  • 5.4 One-size-fits-all /48 subnet
• 6. ICMPv6 and Neighbour discovery
  • 6.1 ICMPv6 protocol
    • 6.1.1 ICMPv6 packets
    • 6.1.2 Error messages
    • 6.1.3 Informational messages
• 7. Related reports