Video Conferencing Protocols

Video Conferencing is an innovative technology that has been developed to communicate with people anywhere around the world using audio and visual communication. It is possible with a good internet connection on PC, laptops, tablets, or smartphones. This visual communication between people allows sharing of information in terms of audio, video, text message, images, etc.

Video conferencing enables users to interact with each other or in groups while seeing the faces for making the meeting or conference lively. Group video conferencing feature is used mostly in companies/organizations to organize meetings, record live sessions, deliver presentations, discuss various projects, etc.

Video Conferencing Networks

Video conferencing works under two types of networks and they are −

  • Circuit Switch − This method relies on establishing the connection, transfer of data, and releasing the connection so full path address will be available to all the data units.

    More reliable as the single bit is used for data transmission at the sender's end

  • Packet Switch − Before the data is sent through the transmission channel they are divided into packets. Data transfer through the channel is made directly, where data units have information about the receiver address.

    Intermediate nodes which are termed routers also perform data transmission which leads to delayed communication. Less reliable as it uses the store and forward method.

Protocols used in Video Conferencing

Video Conferencing has some of the protocols used for visually communicating through the devices connected.

H.3xx is presented as the umbrella communication which is built specifically for video conferencing. These protocols in turn refer to other communication systems regardless of audio, video, data signals, etc.

1. H.320

This protocol uses a circuit-switching mechanism to make video communication. It is referred by ITU (International Telecommunications Union)to represent all the multimedia communications over Integrated Services Digital Network (ISDN).H.320 has inner protocols each designed for specific functions during visual communication −

  • H.221 specifies the design or outlook of the frames used for audio and visual services

  • H.230 specifies signaling process control and data signals

  • H.242 specifies procedures of signaling which include initialization, exchange, and mechanism of sending audio, visuals, and text over the network.

2. H.323

This protocol stack is majorly used by internet applications in real-time for both audio and visual interaction. This works on packet-switched networks for signal processing and gateway methods. This protocol stack consists of four major components such as −

  • Terminal

    This terminal executes on H.323 stack and supports audio/video applications that are used by the local area networks for end-to-end visual communication.

  • Gateway

    Defined for initiating the video call, setting up the connection, working with different media types, switching processes across the network.

  • Gatekeepers

    This acts as the main role to start the calling process under its zone by delivering endpoints to the control services. They are not mandatory but if installed then LAN should use them.

  • Multipoint Control Unit

    Used when a group call is initiated then this unit provides functions to make conferences on H.323 terminals with an MCU connection already been set up by the provider.

3. Session Initiation Protocol (SIP)

SIP protocol initially worked only on delivering voice processes over Internet-based networks. In future years this has been expanded for video, messaging, and sharing of data, even in real-time virtual games. It works on Voice over IP and newer applications must have this as mandatory one to make video conferencing over the supported networks.

  • SIP has two types of messages request and response. Starts with request details and the URI (Uniform Resource Identifier) where these requests are to be sent along with the response code.

  • Sender and receiver ends are found by either knowing the IP address or email address or phone number.

  • This connects applications of the client which supports multiple vendors and it is similar to HTTP protocol for establishing a connection, sending/receiving messages over the channel, and closing the session.

  • Messages are text-based in ASCII format which has a message and its description methods like INVITE, ACK, REGISTER, OPTIONS, CANCEL, and BYE. This defines many other protocols of VOIP that are defined under various Internet Protocol(IP) than native methods defined by ITU.

  • It guarantees end-to-end delivery, encryption, and authentication process that provides more reliability than former H.323 and H.320 protocols.


Video Conferencing technology has enabled people of all ages to interact with one another or in groups visually or by voice process from a convenient time and place. Real-time applications that are developing over 3G,4G and later to 5G networks make use of these protocols mandatory to enable the video communication feature as an inbuilt one.

Updated on: 28-Mar-2023


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