DHCPv6 Address Assignment

The DHCPv6 relay agent informs hosts to use one of several address assignment methods.

Basic DHCPv6 relay assignment
The DHCPv6 relay agent relays the DHCP messages from clients and other relay agents to a list of destination addresses on the same VRF as the interface on which the client resides or on a different VRF. The list of destination addresses includes unicast IPv6 addresses, the All_DHCP_Servers multicast address, or other user-defined IPv6 multicast group address.
DHCPv6 prefix delegation
The DHCPv6 relay agent relays all the DHCPv6 messages (which can contain the DHCPv6 options) that are to be relayed across the DHCPv6 client and the server. The relay agent does not access or extract the information in the prefix delegation option.
Relay chaining
DHCPv6 messages can be relayed through multiple relay agents. The Relay-Reply message from the server is relayed back to the client in the same path it took to reach the server.
Relay-message option
The DHCPV6 relay agent includes the relay message option in all RELAY-FORW messages.
Remote-ID option
The DHCPv6 relay agent supports the Remote-ID option (option code 37). No user configuration is necessary for this method. The DHCPv6 unique identifier (DUID) of relay agent is used as the remote ID.
Interface-ID option
The DHCPv6 relay agent supports the Interface-ID option to identify the interface on which the client message was received. No user configuration is necessary for this method.