As you will see here, there are two kinds of IPv6 address autoconfiguration. One of them is the old and well know way to automatically configure IP address from IPv4 world, DHCP. The other way to make the autoconfiguration in IPv6 world in new, and really interesting way, as it leaves the hosts the ability to make the autoconfiguration by themselves without the need to communicate to anybody else on the network.
IPv6 is meant for various purposes but one main purpose it serves is that it makes life of the network administrators easier, especially when it comes to dealing with vast address space provided by IPv6. IPv6 address number is fairly bigger than IPv4. In order to make things work out of the box, automatic address configuration was created.
As a result, an IPv6 host can configure for itself complete or part of the address settings automatically, which depends on the type and method it uses for autoconfiguration. The method types include:
- Stateful autoconfiguration
- Stateless autoconfiguration using EUI-64 addressing process (SLAAC)
Stateful autoconfiguration is a method in which a host or router is assigned its entire 128-bit IPv6 address with the help of DHCP.
Stateless autoconfiguration or SLAAC is that second method in which the host or router interface is assigned a 64-bit prefix, and then the last 64 bits of its address are derived by the host or router with help of EUI-64 process.
This process in fairly simple and explained in a separate article here.
SLAAC uses NDP protocol to work and NDP is another thing that I have written about.
After all those article that you have here to read it will hopefully be clear how this technology enables all host on the IPv6 network to have their own globally unique IPv6 address without the need for having someone else configure it for him.
If you think that there is no better way to do things but to do it yourself, then you will be convinced that there is no better way of configure the IP address on host but to give him the ability to do it by himself. There will be no other servers, routers or anything else that can fail and leave the host without the address. From my perspective this is the reason that SLAAC technology is brilliant.