Concepts
Multicast addresses used by DHCPv6
DHCPv6 uses the multicast address FF05::1:3 to identify all site-local DHCPv6 servers. It uses the multicast address FF02::1:2 to identify all link-local DHCPv6 servers and relay agents.
DUID
A DHCP unique identifier (DUID) uniquely identifies a DHCPv6 device (DHCPv6 client, server, or relay agent). A DHCPv6 device adds its DUID in a sent packet.
Figure 68: DUID-LL format
The device supports the DUID format based on link-layer address (DUID-LL) defined in RFC 3315. Figure 68 shows the DUID-LL format, which includes the following fields:
DUID type—The device supports the DUID type of DUID-LL with the value of 0x0003.
Hardware type—The device supports the hardware type of Ethernet with the value of 0x0001.
Link layer address—Takes the value of the bridge MAC address of the device.
IA
Identified by an IAID, an identity association (IA) provides a construct through which a client manages the obtained addresses, prefixes, and other configuration parameters. A client can have multiple IAs, for example, one for each of its interfaces.
IAID
An IAID uniquely identifies an IA. It is chosen by the client and must be unique on the client.
PD
The DHCPv6 server creates a prefix delegation (PD) for each assigned prefix to record the following details:
IPv6 prefix.
Client DUID.
IAID.
Valid lifetime.
Preferred lifetime.
Lease expiration time.
IPv6 address of the requesting client.