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Introduction to the MBone

Since the MBone software and tools are developed at a diverse set of sites, it is difficult for the novice user of MBone videoconferencing to determine where to begin. This page is intended to help people in getting started in using the multicast backbone (MBone) for videoconferencing. It provides

List of items needed to participate in a MBone Session
MBone tools and binaries
User guides for the MBone tools
Useful and required peripherals
Links to MBone Sites
Reference books and papers
The best way to get started in using the Mbone is to first review the section containing the list of items needed to participate in a MBone Session. Then pick up the binaries for your platform from the tools and binaries section and install them. To learn how to use each of the tools refer to the user guides for the tools.

Many of the comments on these pages are written in the first person, but do not be fooled--this is not the experience of any one single person. The first person is used only as a narrative convenience.

You may also want to check out our camera control and conference controller tools for adding remote control capabilities to videoconferencing.

What do I need to participate in a MBone Session ?


The MBone is still somewhat experimental and is not yet available on every operating system and subnet by default. The easiest way to determine if you are able to receive multicast packets on your local machine is to run sdr. If the list of sessions has entries in it and they stay in the list for more than ~20 minutes then you are on the MBone and your machine is receiving MBone broadcasts so skip 1 & 2 below. In order to participate in an MBONE session you need a few things :
  1. A multicast capable kernel. Many of the operating systems now come multicast capable. There are patches available for many of the operating systems that are not delivered multicast capable.

  2. Your subnet needs to be on the MBONE. In other words, multicast packets need to be being forwarded to your machine. The easiest way to check if you are on the MBone is to run the sdr tool and see if any sessions show up. Run it for about 10 minutes and if nothing shows up in the session list you are not on the MBone!

  3. The multicast videoconferencing applications. You need a minimum of sdr, vic, and vat (or rat). It is also nice to have wb on hand. (Sdr and rat were developed at UCL. Vic, vat, and wb were originally developed here at LBNL by Van Jacobson's group. UCL is also maintaining updated versions of vic.)

  4. Multicast debugging tools are also helpful in diagnosing problems. the primary tools available are mtrace, mrinfo, and rtpmon. Mtrace allows you to do a multicast traceroute from a receiver to the source of a multicast on a particular address. Mrinfo allows you to query a multicast router and determine its local configuration. Rtpmon allows you to monitor the RTP receiver reports as they are received. NOTE: mrinfo and mtrace have to run as root.
NOTE : It is a really bad idea to remotely log into a machine and start up vic and vat on the remote machine because you will not get audio and the X protocol is horribly inefficient at remotely displaying vic windows and will bring an ethernet to its knees.

As a further note, if you are connecting via an ISDN line from home there may be some things you need to do to get routing of multicast packets over the ISDN line. You will also probably want the video transcoder to convert the video to a lower rate format before sending it down the ISDN line.

Peripherals for MBone videoconferencing


To participate in a videoconferencing session over the MBone there are a few things that you need. The following section will give you some idea of the minimum requirements to be a participating member in a videoconference (not just listen in) and lists some of the hardware we have used and like.

Guides to Using the Videoconferencing Tools


This section is still under development so please have patience. I have a beginner's guide and a advanced section for most of the tools. The beginner's guides are intended to provide you with enough information to get you from "What is this tool anyway?" to "I can do this!" The advanced user information sections document some of the lore and magic incantations that I have accumulated with respect to the MBone tools and routing protocols. This information is intended to augment (not replace) the manual pages supplied with the tools. Comments regarding content of the pages are welcomed.

VAT (audio tool)

RAT (Robust Audio Tool)

VIC (video tool)

DEVSERV and CAMCLNT (remote camera control tool)

CONFCNTLR (videoconference control tool)

SDR (session directory tool)

Multicast Routing

Tools and Binaries to download


This site is not a mirror site and is instead manually maintained so there are no guarantees that it contains the latest versions of the tools, binaries for all architectures, or all the possible tools. This site is simply meant to help get you started. The groups that are most actively developing new versions of the MBone videoconferencing tools are the MASH group at UC Berkeley and the UCL Multimedia Research Group, so you might want to check their sites for binaries first.

To go to the ftp directory for a particular architecture just click on the architecture. If the architecture or binary you are looking for is not listed it probably exists at the actual site building and maintaining the individual tools so try the WWW pointers. For brief explanations of what each of the tools are used for see the list of items needed to participate in a MBone Session. To learn how to use the tools refer the guides to the tools.

There are versions of MBone binaries in this directory for the following architectures/operating systems.

The corresponding manual pages are in Manual pages.

If you want additional tools not listed above, other places to look are:

Links to MBONE Sites


URLs for getting more information about the MBONE and getting the MBONE tools are listed below. You may already have these tools installed on your machine. If you download the tools, I highly recommend the alpha-test version of the vat tool rather than the older version. The following URLs also have information about the several mailing lists and meetings that discuss MBone and videoconferencing related issues.

Bibliography

Introduction to the MBone Page
Please also visit the
Lawrence Berkeley National Laboratory Home Page. Distributed Systems Department Home Page. Distributed Collaboratoratories Home Page.

This document was last updated on April 11, 2005, and is located at http://www-itg.lbl.gov/OldMisc/mbone/homepage.html.

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