JAMM - Technical Information




JAMM uses a replicated architecture, which is fairly uncommon among collaboration transparency, also called application sharing, systems.

Central Application with Graphics Distribution

The common approach for application sharing is where a single instance of an application is run on a host machine and its graphical output is distributed to the participants. This centralized approach is used by many collaboration transparency technologies: SharedX, XTV, ShowMe SharedApp, Microsoft NetMeeting, Timbuktu. In fact, Microsoft and PictureTel have proposed a standard for this approach, called T.SHARE, that the ITU is considering for inclusion under T.120 Data Protocols for Multimedia Conferencing.

The graphics distribution approach is illustrated in the figure below. Distributing the graphics consumes substantial network bandwidth, even when the graphics information is compressed.

Graphics Distribution Architecture

Replicated Applets with Event Distribution

JAMM runs a copy of the applet on each participant's local machine and distributes the input to all participants, illustrated below. This allows the application to run locally. Also, the bandwidth required is substantially less. Only the inputs are distributed and the graphics output is generated locally for each participant. The bandwidth savings becomes apparent when we consider that the centralized approach also must recieve inputs from each user. The event distribution approach instead multicasts these inputs to all participants.

JAMM's Replicated Architecture

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James "Bo" Begole
April 12, 1997