3.1.b Identify, implement and troubleshoot IPv6 addressing and subnetting

3.1.b [iv] Autoconfig/SLAAC, temporary addresses [RFC4941]

Dynamic Host Configuration Protocol (DHCP) has allowed systems to obtain an IPv4 address as well as other information such as the default router or Domain Name System (DNS) server. A similar protocol called DHCPv6 has been published for IPv6, the next version of the IP protocol. However, IPv6 also has a stateless auto-configuration protocol unlike IPv4.

Stateless address configuration means that the client picks their own address based on the prefix being advertised on their connected interface. All Cisco devices have the ability to participate in Stateless Autoconfiguration (SLAAC). By default, SLAAC does not provide anything to the client outside of an IPv6 address and a default gateway. Additional configuration on the server is necessary before the same information can be provided to the client as Stateful DHCP. Moreover , it is important to note that SLAAC most commonly uses eui-64 format for address assignment. This means that IPv6 addresses will be built from a combination of the Layer 3 subnet prefix and the MAC address of the client. The requirement for SLAAC is that the LAN segment must use a /64 mask. Cisco routers support both stateful and stateless DHCP. Stateless DHCP does not track IPv6 address bindings per client.

It, rather, uses DHCP to hand out domain-names, DNS servers and other relevant client information.

Adam, Paul (2014-07-12). All-in-One CCIE V5 Written Exam Guide (Kindle Locations 2328-2329).  . Kindle Edition.