3. Background
3. Background
The IPv6 specification provides the foundation and design for IPv6. Relevant work in IPv6 that implementers should study includes the IPv6 specification [RFC 2460], IPv6 addressing architecture [RFC 2373], IPv6 stateless address autoconfiguration [RFC 2462], IPv6 neighbor discovery processing [RFC 2461], and DNS dynamic update [RFC 2136]. These specifications enable DHCP to work with IPv6, providing powerful stateful autoconfiguration and automatic registration of DNS hostnames.
The IPv6 addressing architecture specification [RFC 2373] defines the address scopes that can be used in IPv6 implementations, as well as various configuration architecture guidelines for network designers of IPv6 address space. Two advantages of IPv6 are that multicast must be supported, and nodes can create link-local addresses during initialization. The availability of these features means that clients can use their link-local addresses and well-known multicast addresses to discover and communicate with DHCP servers or relay agents on their links.
IPv6 stateless address autoconfiguration [RFC 2462] specifies the process by which nodes can autoconfigure addresses based on router advertisements [RFC 2461], and the use of valid lifetimes to support renumbering of addresses on the Internet. In addition, it specifies the protocol interactions by which nodes begin stateless or stateful autoconfiguration. DHCP is one tool for performing stateful autoconfiguration. Compatibility with stateless address autoconfiguration is a design requirement for DHCP.
IPv6 neighbor discovery [RFC 2461] is the node discovery protocol in IPv6, which replaces and enhances the functionality of ARP [RFC 826]. Understanding IPv6 neighbor discovery is strongly recommended for implementers to understand IPv6 and stateless address autoconfiguration.
DNS dynamic update [RFC 2136] is a specification that supports dynamic updates of DNS records for both IPv4 and IPv6. DHCP can use DNS dynamic update to integrate address and namespace, supporting not only autoconfiguration but also automatic registration in IPv6.