|PPNCG Information Pages : Video-conferencing : Data Sharing (Application window sharing etc.) : 1) Datasharing component of Netmeeting|
|In this section we are assuming that the data sharing technology
is T.120 and the client is the data sharing component of Netmeeting.
Other possibilities are discussed elsewhere in this area.
It should be noted that THE USUAL AUDIO/VIDEO MULTIPOINT MCUs to which we have access DO NOT SUPPORT MULTIPOINT T.120 DATA SHARING.
It is technically feasible to create conferences in which both kinds of multipoint unit are available to the same conference (see for example the optional T.120 support for the Radvision ViaIP MCU), but we do not usually have that luxury on the MCUs available to us. Hence these notes.
Unlike Audio/Video conferencing - where a multipoint conference definitely needs a multipoint conference unit (MCU) to mediate the call - data sharing between multiple clients can be achieved on an ad hoc basis by establishing a connected chain of point to point connections.
Here's the key issues:
* The H.323 client software (ViaVideo or Zydacron OnWAN as the case
may be) would like to use the data sharing component of Netmeeting
in the background as a
helper application in order to offer data sharing.
Therefore, to achieve this magic in a multipoint session, you will
NEED TO DECOUPLE THE NETMEETING APPLICATION FROM THE H.323 A/V CLIENT.
How to do this is shown below.
|When we say "NetMeeting", we're referring to a recent distribution of
NetMeeting 3.01, appropriate for your flavour of Windows OS.
This is where confusion arises, since (as was commented above) our videoconferencing applications expect to use Netmeeting as their helper application for integrating data-sharing into a session. You need to de-couple Netmeeting from the audio/video application: consult the relevant section from the menu below for how to do this.
In what follows, we assume that the reader has at least an initial familiarity with setting up their respective H.323 software for an MCU call.
When NetMeeting is used and data sharing is enabled for the first time, it will want to perform a little additional installation: we assume that this step was already done at some time in the past. If not, then please do it before following the subsequent recipes.
NetMeeting needs to be configured for making its calls
directly, without the use of a Gatekeeper. Visit its menu:
Tools -> Options -> General -> Advanced Callingif you want to verify this.
Of course, we are also assuming that any relevant network
firewall restrictions have been lifted.
|The most convenient way we have found of using Netmeeting for multipoint
data sharing, in the absence of an MCU supporting multipoint
T.120, is to use the JVCS-documented method, see
http://jvcsbook.ja.net/docs/datash/ and the setup instructions at
If in doubt, then you should check with the JVCS documentation to find out whether you are eligible to use this facility.
Provided that Netmeeting has been de-coupled from the OnWAN or
ViaVideo software respectively, as described in the present notes,
then the JVCS documentation should contain all of the information
which you need.
|If you do not use the JVCS method, on the other hand, then these notes may help.
Evidently, the establishment of a connected chain or net of point to point connections needs a little liaison between the participating sites(!)
As far as I can see, it doesn't really matter which end initiates the call,
nor which existing conference partner they establish the call to.
Naturally, if there are participants on both sides of the Atlantic it's
probably a good idea to have only one transatlantic link, and have the other
participants calling near-neighbours. But this is something that I guess the
conference organiser would need to co-ordinate.
One should be aware that Netmeeting data sharing, like any other means of exchanging files, represents a possible route of infection for viruses, trojans etc.
Also, configuring Netmeeting to automatically accept incoming calls could leave one open to intruders.
The usual kinds of precautions should be taken against these potential
Answers in this category:
The above complexity is a work-around for doing multipoint data sharing in conjunction with an MCU that only supports audio/video conferencing.
If you are doing point-to-point videoconferencing, then you can do data
sharing by simply following the normal instructions; this complexity is
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