[AG-TECH] IGMPv3, Source Specific Multicast, fully supported in Windows XP

Bill Nickless nickless at mcs.anl.gov
Fri Aug 16 14:00:13 CDT 2002

At 01:31 PM 8/16/2002 -0500, Ivan R. Judson wrote:
>This is something that I have a hard time thinking about.  My concern is
>mostly based around the fact that these seem to be things that AG
>Nodes/Users need to have in the technology portfolio.  Ie, can the user
>send more than one stream?  What format? What quality?  If not, who's
>doing it for them?  Is this a network service?  Does it need to be

It seems to me that the best place to code a video stream into multiple 
formats is at the sender.

  - The sender has the raw, uncompressed video available by virtue of
    the direct connection to the camera.  This eliminates the need for
    decoding a compressed stream and re-encoding it somewhere else.

  - In the multicast transport model, the incoming traffic level is
    generally much larger than the outgoing traffic.  Thus, there is
    usually plento of bandwidth available for multiple outgoing streams
    at the sender.

  - The receiver knows best which streams are "interesting".  By
    choosing which (S,G)s to join, the receiver can help the network
    deliver only the traffic that is necessary for the displays
    currently visible at the local site.  Generally, bandwidth
    limitations are closer to the edge than the core of the Internet.

Bill Nickless    http://www.mcs.anl.gov/people/nickless      +1 630 252 7390
PGP:0E 0F 16 80 C5 B1 69 52 E1 44 1A A5 0E 1B 74 F7     nickless at mcs.anl.gov

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