Apple Remote Desktop Protocol (ARD) – Original protocol for Apple Remote Desktop on macOS machines. Appliance Link Protocol (ALP) – a Sun Microsystems-specific protocol featuring audio (play and record), remote printing, remote USB, accelerated video HP Remote Graphics Software (RGS) – a proprietary protocol designed by Hewlett-Packard specifically for high end workstation remoting and collaboration. Independent Computing Architecture (ICA) – a proprietary protocol designed by Citrix Systems NX technology (NoMachine NX) – Cross platform protocol featuring audio, video, remote printing, remote USB, H264-enabled.