Cell Relay Archive

[marke@fore.com (Marke Clinger)]

At 11:13 PM 4/1/95, Robert P. Vietzke wrote:
>Who out there has actually -implemented- video on ATM, and what has been the
>user's response?
>>We are aware of several University projects utilizing Newbridge JPEG and
>>would
>be interested in hearing about other vendors and experiences...

Hi Rob,

Here is a write up on a trial done by NASA. It was covered in Comm Week,
Network World, etc. I helped implement this, so if you have any questions
feel free to contact me.

The AVA-200 mentioned below divides the screen into "tiles". Each tile is
put into an AAL5 PDU and sent over the ATM network. The display side is
entirely in software and multicast is supported. Therefore, a single video
feed can be sent directly to as many desktops as you have on ATM.

If you are interested in IP over ATM video applications, please let me know.

Marke

______________________________________________________________________
Marke Clinger                             Direct: 412-933-6272
Sr. Systems Engineer                      Main:   412-933-3444
FORE Systems                              FAX:    412-933-6200
174 Thorn Hill Road                       E-Mail: marke@fore.com
Warrendale, PA 15086

______________________________________________________________________________


           NASA Launches Desktop Video Conferencing

                                 September 1994


Scientists at the National Aeronautics and Space Administration (NASA)
spend a lot of time working on complex topics like Numerical Aerodynamic
Simulation (NAS). What they need is an easy way to simultaneously share
their data, while seeing and talking to each other--right from their
workstations.

This is why a recent demonstration of one-to-many desktop video
conferencing based at the Ames Research Center at Moffett Field, CA,
created such a stir among the scientific community at NASA. For this
demonstration, the Ames Center joined with the Langley Research Center in
Hampton, VA, and the Lewis Research Center in Cleveland, OH. Each site was
equipped with an AVA-200 ATM video adapter connected to an ATM switch both
from FORE Systems. The interface between the two is a 100 Mbps TAXI
connection.

AVA-200s and video cameras were set up at each site. Video from all three
sites was displayed on a single workstation at each location. The display
quality was described by users as "impressive" and there was virtually no
delay, even across an ATM connection of more than 10,000 miles.

During the demonstration, uncompressed video was sent over ATM permanent
virtual circuits (PVCs), at 24 frames per second. Uncompressed video is
needed for applications requiring high resolution, such as medical imaging.


At each NASA center, Sun SPARCstations hosting FORE's real time display
software were linked to ForeRunner ATM switches at either 100 Mbps or 140
Mbps. The ATM switches themselves were connected by T3 (45 Mbps) lines
between Moffett Field, CA, and Hampton, VA, and Moffett Field, CA, and
Cleveland, OH. The lines are part of NASA's Aeronet network and were
supplied, along with the ATM switches, by the Program Communications
Support Group in Huntsville, AL.

Currently, the AVA-200 supports speeds up to 30 frames per second for
full-motion video. FORE also plans to offer an option that would meet the
JPEG standard for video quality.

Versions of the real time display software are also being developed for
UNIX platforms from IBM and Silicon Graphics, Inc. Also, a faster interface
conforming to the 155 Mbps OC-3c, SONET/SDH standard is on the way for the
AVA-200 system.

The AVA-200 offers users who choose to run at lower frame rates a dramatic
improvement in playback quality. Instead of repeating a frame several times
during playback, FORE's real time display software progressively merges one
frame with the next. The result is a smoother, more natural-looking
playback, even at speeds as low as 4 frames per second.

With the AVA-200 ATM Video Adapter system from FORE, NASA scientists around
the world can hold face-to-face meetings--without leaving their
workstations!