[AG-TECH] Initial notes on setting up venues

[Chris Geddings]

Just wanted to drop some notes on my work torwards setting up a private
venue type server here in the Johnson and Johnson lab.  Any comments are
greatly appreciated, as I know I've got some things wrong, and have some
incorrect conceptions.

To setup a converence, you have to create an advertised multicast
session/group.  Each type of data involved in the converence requires a
different multicast group.  For example, in a simple video converence,
you may only have audio and video.  The audio stream will travel in one
multicast group, and the video on another.  One tool for creating the
advertised sessions is 'sdr'.

I am unclear on how to bind a group to a specific multicast address. 
When I create a session in sdr, it seems to dynamically grab addressess
on its own, based on my ttl scoping.  Though I've seen mention of "Admin
Scoping", I'm unclear of how to do this with sdr.  I'm very unclear on
how to set up
a multicast group outside of sdr.  Based on what I've seen in the mail
list
archives and on the various access grid pages, sdr used to be the way
the
various sessions were advertised, but is no longer.

I'm also unclear on how ports work with multicast.  Every multicast
"group" is represented by what I traditionally think of as an IP address
(well, it is still an IP address, the abstract just works differently). 
What role does the port play?  Does that relate more to a port on each
of the unicast addresses that are in the multicast group?

>From what I can tell, the "Venue Server" (http://venues.accessgrid.org)
provides the following functions:

	1) A web server for the purpose of authentication and providing a
simplified method of delivering the multicast connection information to
vic on the display and video capture units and rat on the audio capture
unit.

	2) A MUD to allow text based communications.

I'm unsure of any other back-end type functions the Venue Server
provides for the Grid.

Please let me know what I have wrong above and if you can fill in some
of
the gaps I've mentioned.

Thanks,
Chris