All things related to multicast

["James Martin" <>]

At 04:45 PM 9/14/2001 -0400, Richard Mavrogeanes wrote:
> Folks,
>
> The VBrick can be configured to join its own multicast, and this
> is the default configuration.  This is because certain poorly designed
> switches flood (cgmp) if there is not at least one client listening to
> the multicast.  The feature can be disabled.
>
> I believe Tuesday's event was one of the largest multicast events, and
> there were many people showing our video on the floor at N+I in Atlanta
> via I2 multicast.
>
> I would certainly like to receive some evidence that this is true, and
> if anyone can assist me in this regard, please feel free to contact me.

        I can certainly confirm this. I'm the person in charge of IP 
Multicast for the InteropNet, the production network as well as the 
experimental labs. We've had global multicast natively on the show network 
ever since the spring of 1994, and for the last few shows, that feed has 
come from I2. At various times multicast has gotten use ranging from 
moderate to nearly nothing. However, this all changed last Tuesday.

        We had a large plasma screen in the iLabs intended to demonstrate 
high rate HDTV over I2 (I'm sure some of you remember the profusion of 
"HD-underwater.mpg" sessions that we're being announced. Unfortunately, 
that was for us). We came in Tuesday morning and were preparing for the 
first day of the show when word came in about the initial plane crash into 
the towers. Our I2 Lead, Roy Hockett was able to switch the stream to a CNN 
broadcast that he was sourcing from UMich. We began attracting exhibitors 
to the display even before the showfloor opened. Once the attendees were on 
the floor, the crowd had grown to well over a hundred.

        By this point, three things had happened. The crowds around the 
one display had grown so large as to constitute a fire hazard, all the 
major news web sites had completely melted down, and CNN was being 
multicast from several sources. We then started loading multicast tools on 
every PC in the NOC, from the one driving the large video wall to people's 
individual laptops. By 10:30 (about half an hour after the floor opened) we 
had at least 3 large displays as well as a number of normal monitors turned 
out towards the plexiglass walls.

        Soon after, we had a good number of exhibitors come and ask how to 
get "the CNN viewer software". By noon, quite a few of the exhibitors on 
the floor had a live feed and were drawing a good crowd. We closed the show 
early that day, to allow folks to attend to all of the obvious personal 
business, but reopened for the next two days. During the whole time, 
between the NOC folks and the helpful exhibitors, we kept news coverage 
flowing to everyone at the show.

        I'd hate to see what this would have looked like with replicated 
unicast.

        - Jim