They may also carry real-time data and video, or any combination, including videotelephony. A gateway performs protocol translation and transcoding. This is an optional element in an H.323 system. The MCU is responsible for mixing audio and video. The MC controls conference resources by determining which, if any, of the audio and video streams will be sent.
End users can then refer to the conference name when they wish to join the conference.
MCUs can be implemented in hardware or software. The number required depends on how many and how frequently you conduct multiparty conferences . Not to be confused with a gateway, a gatekeeper is another optional component that performs important control functions in the H.323 system. Basically, it is software that manages the H.323 network. You should use a gatekeeper if the number of terminal endpoints deployed for video conferencing are likely to affect the network bandwidth requirements.