NT MBone Walkthrough


MBone stands for Internet Multicast Backbone. Propoerly speaking, we are not necessarily using the “real” MBone but just a multicast system with the MBone tools. But we may call it “MBone” anyhow from force of habit.


The MBone tools being used under NT were produced by the Unversity College London.  Additional information, including user guides for each of the components in the MBone – vic, vat, wbd, & nte, can be obtained from http://www-mice.cs.ucl.ac.uk/multimedia/


All of the UCL MBone tools are installed in C:\Program Files\MBone 


The tools found in this directory include:

Sdr.exe                        The Session Directory application  v2.9

Rat.exe                         Robust Audio Tool v3.0.35

Vic.exe                         Video Conferencing Tool v2.8-ucl1.0

Wbd.exe                      WhiteBoarD Tool 1.0ucl4

Nte.exe                        Network Text Editor v1.7.0



Getting on the Multicast System


Most of the activity (starting or joining sessions) is done through the Session Directory tool.  To begin SDR – simply choose “Start” -> “Programs” -> “MBone tools” -> SDR


Or double click the “SDR” program on your desktop.


Session announcements are made when the session is created, and then repeated at an interval of several minutes. The first time you run SDR, there probably won’t be any active sessions visible in the application.  If your machine is correctly configured to send and receive multicast packets over the MBone – you should eventually see some sessions show up in SDR.



When first running SDR – you should click on the “Prefs” button, then click the “You” button and enter information identifying yourself.  This information will be used mainly when creating a new session to identify yourself to others that might join your session.



After entering the information, select “Save & Apply Preferences” to close the window and save the information.


Joining an existing session


In SDR, single clicking the session you would like to join will bring up the Session Information window.



In this window, you can see a lot of information about the session including:  the length of the session, contact information, and the tools used in the session.  The session above will last two hours from 1500 to 1700 and is using audio, video, whiteboard, & text.


At the bottom of the window you see available options to take on this session.  In this example, there are more options than would be available in the normal session window – such as edit and delete.  These are available in this session because the session was originally created from the same machine as is being used to view the session information.


If you want to enter this session and start all of the tools listed – select “Join.”  You also have the option of inviting others to join the session with you – if you know their user and host name. 


Creating a New Session


To create a new session, from the SDR utility – select “New.”



You will see two options – “Create advertised session” and “Quick Call” – in most cases we will just be creating an advertised session but quick call is useful to quickly generate a session with certain tools and invite specific users and hosts to join.


Select “Create advertised session”



In this window, provide a name for your session and basic description of its purpose. These entries are mandatory. Select “Next” when finished.



Select the type of session you are creating and click Next.

Note:  usually this will be “Meeting”



Now specify the start time and length of the session.  Remember to allow enough time to complete your activities so the session doesn’t expire before you are finished.  You can always kill the session on manually if you end early.  Click next when finished.


Select the scope that you wish the traffic to be sent. 



Select the tools you would like to use in your session and the format they will use.  The checkboxes next to the tools allow you to toggle whether you will use encryption.  Encryption can be configured a little later.



Enter your contact information so users will know who started this session and show how to contact you.  If you followed instructions and entered the information in SDR earlier – then this should already be filled for you.



You can configure encryption if you want to use it.  Usually this won’t be used.  The only option available in the NT tools installed is Des.


A final confirmation displaying all of the settings chosen for this session will be displayed.  To create the session, hit “Accept”


Your session should now appear in the SDR utility and should start to become available on the multicast system.



Follow instructions above for Joining your session.  You can edit the information you entered about your session later by clicking on it in SDR and choosing “Edit.”  To kill the session, follow the same procedure but choose “Delete.”


After you Join a Session


Selecting “Join” in the session information window will put you in the session and run all of the tools listed automatically.


In this example, it would run RAT (Audio), VIC (Video), WBD (Whiteboard), and NTE (Text).


RAT (Robust Audio Tool)



In Rat, you can see a list of users connected to the session and have controls that allow you to manipulate incoming and outgoing audio.  When you first start the tool, your microphone will be muted. 


If you have trouble using the audio you should make sure that other audio inputs are disabled.  To do this double click the speaker icon on your task bar near the clock.


This will bring up the “Master Out”


Select “Options” and “Properties”

In Properties -  switch to “Recording” and click all of the check boxes in the list below.



Choose OK and you should now be at the “Master Record” controls.



In this window – mute all inputs except “Mic” 


Now to begin sending audio – In Rat, turn off the Mute button above the microphone indicator bars as seen below:



You may need to adjust the gain on the microphone to an acceptable level each time you start RAT.  You may also need to adjust the volume level of incoming audio.


The options in RAT should already be set to appropriate values be default.  If you experience problems with the mic not cutting on soon enough or chopping off the first part of your words/audio, select “Options” and turn off “Suppress Silence.”




VIC (Video Conferencing Tool)


When first joining a new session you create, your Vic window may look like this:



To begin broadcasting video:


Make sure your camera is connected correctly to your capture card.  If you are using the Winnov camera (the small round camera) – then it should be hooked in to the round MXC port (to the right of the yellow composite port).  You can use a different camera than this one – but you must launch “Videum  Configure” (Accessible From Start -> Programs -> Winnov Videum -> Utilities) and select the port you want while VIC is running and transmitting.


You can tell the camera is functioning and has power if the green light shows up in the front of the camera.


Click the “Menu” button



On the Dell workstations, the correct device, port, and format should be selected by default.  You will need to select the frame rate and speed.  An ideal connection should be about 600kbps and 15fps.  When you are ready to begin transmitting – click the transmit button and hit “Dismiss”



When returning to the Vic window – you see a small version of the data being transmitted.  There will be an entry here for everyone in the session, click on an entry to see a larger version of the video.



There is also a Whiteboard (WB) tool which is pretty much self-explanatory.  A good strategy with WB is for each site to pick a different color to write on the shared whiteboard.


This completes the “how to” for users.  It may seem like a lot of steps, but in fact you will usually just need to click on a session in SDR, click on Join, and then start video transmitting and enjoy your conference.



We include some details here for the system administrator:


Configuring the software


In order for these applications to run correctly there must be some environment variables correctly set on the machine:


HOMEDIR  C:\Program Files\Mbone

And  PATH should contain C:\ProgramFiles\Mbone

The Windows NT interface to do this is shown below. To edit the environment variable under NT – select “System” from the “Control Panel” – select the “Environment” tab – select PATH under the “System Variable” block – edit it to include the path listed above – then click set.




Please send any questions or comments on these directions to help@netlab.gmu.edu.