Protocol Modules The protocol modules implement protocol-specific functionality. The available protocol modules are: Protocol Modules cui CUI dhcpv4 Implements DHCPv4 (Dynamic Host Configuration Protocol for IPv4) client and relay. isc_dhcp isc_dhcp radius Allows Access-Requests, Accounting-Requests, CoA-Requests and Disconnect-Messages to be sent during request processing. wimax Implements WiMAX authentication over RADIUS.