Unicast Address Sub-Option
In some network topologies, it is preferred to have a trusted network element between the DHCP client and the DHCP relay agent that adds the DHCP relay-agent-information option but does not set the giaddr field. This document defines a new sub-option for the relay-agent- information option. With this sub-option, the DHCP relay agent will always unicast the messages towards the trusted layer 2 DHCP relay agent with a MAC address that is known in the network. The new sub- option is called the "unicast-address" sub-option.