Multipoint Control Unit (MCU)

Multipoint control unit is a device that allows to organize group video conferences between videoconferencing endpoints. Therefore, a MCU server connects endpoint devices that can work with different protocols, most often via H.323.

Most importantly, during a multipoint conference session, MCU server manages multiple endpoints at once, coordinates their functions on the video data processing, and forwards the flow of media streams between them.

MCU-server is a hardware/software device that consists of a MC controller (Multipoint Controller) and MP processors (Multipoint Processors). Multipoint Controller deals with coordination of the media stream processing parameters between endpoints. In addition, the controller supports the H.245 protocol. The important functions of Multipoint processors are processing, mixing and switching of multimedia streams.

What is the main difference between MCU Server and Software Video Conferencing Server?

It is quite easy to assume that they are the same. However, this is not correct. There are major differences between MCU Server and a software Video Conferencing Server. The core difference lies in their respective functions, features as well as the underlying technology, architecture.

Unlike software video conference server, MCU server conducts group video conferences under the principle of mixing media streams, i.e. mixing and re-encoding participants’ video conferencing streams in real time. For example to create a picture-in-picture effect imposes very strict requirements on the computing capacity of MCU server.

More importantly, software servers implement multiplexing pattern of the data streams, which implies no transcoding is done by them. A server just redirects the media streams of the video conference participants. Compression/decompression and media streams mixing undergoes in endpoint devices aka client applications, which do most important job.

I have a Video Conferencing Endpoint. Do I need an MCU server?

Video Conferencing Endpoints are essentially standalone equipment that can be used to initiate or join video conferences. Most endpoints come with multiparty licenses. These licenses are either inbuilt or can be purchased as top-up. So then what is the main use of MCU Servers? MCU Servers are required when an organization needs to go beyond the limited capabilities of video conferencing endpoints. By limited capability the first thing is number of parties that can be present in a single video conference. MCU has a much higher capability in this term. Second major capability difference is the number of simultaneous conferences possible. Endpoints can have just one! MCU has ability to handle multiple simultaneous group conferences from day one.

Is MCU Server possible as a software?

An MCU Server can come as a hardware or a software. Earlier, mostly the MCU Server was available as a hardware, i.e. you buy a box. Some professionals in video conferencing still associate MCU Server as a “hardware”. However, this is not correct. Today the best technology of MCU Server is available as a Software. 

How to decide between MCU Server and Video Conference Server Software?

If you have the need to exclusively connect H323 or SIP endpoints in a conference, MCU Server is the solution to go for. MCU server will help you add the H323 or SIP endpoints in address book. It will allow you to create video conferences and start them, control layouts, record etc. It will not be giving you many options for desktop, mobile, webRTC based participants. 

The other scenario is that you have either no or very few participants with H323, SIP endpoints. This means most of your participants are desktop, mobile, webRTC based. In this case, you need a Video Conference Server software.

Does this site provide Video Conference Server or MCU Server?

This site provides both the MCU server in software format and Video Conference Server in software format. You can download and install our Video Conference Server from the download link on the top of this page. Or, click here to download it.

If you require to test our MCU Server instead, you can do so by downloading it by following the instructions below.

How to install MCU Server Software

Step 1 Download VMWare Workstation Pro

This is to run the actual Virtual Appliance we will run in the Step 2. Workstation Pro is a paid software, trial is available for 30 days. We recommend version 15.

VMWare Workstation Pro for Windows

You can find Linux VMWare version as well on their site.

Install. If you face issues, try googling, mostly it’s simple to figure out. Remember, in BIOS, virtualization settings must be enabled.

You can also email us at for support with this at any step.

Step 2 Get Download Link for MCU Server software by using form below:

This is the actual Virtual Appliance that performs the work on MCU Server. It’s Debian 9 based. Download file is upwards of 1 GB. It is a zip file containing OVF for importing into VMWare as a ready to run Virtual Appliance.

    Step 3 Import the Debian Virtual Appliance (VA) into installed VMWare workstation

    Sometimes, a general error is thrown about the associated config file for the VA, just press “retry” and it should work

    Step 4 Start the VA from inside the Workstation window

    A couple of automated steps and screens will appear, just let it be. Finally, enter the Debian userid and password.

    debian login: user

    Password: 12345678

    If asked, Root Password: 12345678

    Type “ip a” command on the command prompt. It will reveal the IP of the machine you have installed on. This may be different from the one you know because of VM aspect. Just note it. Then open Browser and enter https://thisip in address bar. If https security warning comes, click “proceed” in the advanced section of the browser. You are telling the browser that you know what you are doing.

    Step 5 Send us a file to get your trial license

    On the dashboard, you will see a procedure to generate and send us a file for activating the trial license for your MCU. Click “download hardware information”. This file is 200 Byte size only. Just email this file to us at and the number of H323/SIP endpoints’ trial you need. Usually 5 endpoints connections simultaneously is a good for trial purpose.

    Step 6 Welcome to the MCU control panel

    You can see the MCU control panel now. From here you can start creating multipoint conferences with ease. You can use both H323 and SIP protocols, MCU uses them automatically. You can monitor on-going conferences too. Changing layout is supported, both global & local layouts are supported.

    MCU Important Features

    • MCU with up to 256 participants
    • Up to 25 participants per layout
    • Video quality up to Full HD 1080p@60fps
    • Video encoding H.261, H.263, H.264, H.264 High Profile, H.265
    • H.323 / SIP signalling
    • Dual Stream H.239/BFCP up to 1080p@60fps
    • Third party equipment interoperability

    MCU Conference Features

    • Scheduled and ad-hoc conferences
    • Call-in / call-out
    • Meeting PIN code access
    • Dual stream PDF, JPEG, BMP, TIFF, PNG
    • Email notification
    • Recording
    • Up to 32 conferences simultaneously
    • RTMP streaming
    • Technical/statistic information

    MCU Call Control Features

    • SIP/H323/RTSP calls
    • Re-dialing function
    • Call forwarding
    • Call priority

    MCU Layouts Features

    • Symmetrical, individual, automatic layouts
    • Static and dynamic layouts manipulation
    • Voice activated layouts

    MCU Features for Participants

    • Disconnect notification
    • Preview
    • Visibility control
    • Gain control
    • Camera control

    MCU Address Book

    • SIP address
    • H323 address
    • Local address book
    • LDAP/Active Directory
    • Groups
    • Import/export

    MCU Web Admin Control Panel

    • Web control panel
    • Call history
    • System events
    • User profiles
    • SNMP, NTP
    • Journaling

    MCU Video Resolutions

    • Receiving Video: HD (1920 x 1080p), WSXGA+ (1680 x 1050), UXGA (1600 x 1200), SXGA (1280 x 1024), WXGA (1280 x 768), HD (1280 x720p), XGA (1024 x 768), SVGA (800 x 600).
    • Transmitting Video: CIF (352 x 288 px), SD (720 x 480 px), 720p (1280 x 720 px), 1080p (1920 x 1080 px).

    MCU Audio Standards

    • G.711, G.719 (Siren22), G.722, G.722.1 (Siren7)
    • G.722.1C (Siren14), G.723.1*, G.726*, G.728*, G.729*
    • AAC-LD, OPUS
    • DTMF

    More information on MCU Server architecture

    There are several types of configurations that use MCU server

    Centralized Conference: A MCU server is necessary to perform centralized group video conferences. During such conference, all endpoint devices communicate only through the MCU server.

    Decentralized Conference: During such conference, all endpoint devices can communicate with each other without the MCU server, using Multicast technology only. Although in this case, the MCU server is not an interface between the endpoints, its role is not less important because it controls the exchange of media streams.
    Multipoint control unit

    Hybrid Conference: In this case, endpoint devices which participate in a video conference can perform simultaneous transmission of only audio or only video streams to other endpoints without sending them to the MCU-server. All other media streams can be transmitted only through the multipoint control unit.
    Multipoint control unit

    Mixed Conference: Such video conferences are conducted under the control of MCU-server, which performs the function of a “bridge” for connections of all types (centralized, decentralized or hybrid conference) between endpoints.