151 Xing Distributed Media Architecture (UNIX - MPEG Professional Software)
Description
This article is from the MPEG FAQ, by Frank Gadegast phade@cs.tu-berlin.de with numerous contributions by others.
151 Xing Distributed Media Architecture (UNIX - MPEG Professional Software)
{XDMA} Network Description
The Xing Distributed Media Architecture ("XDMA"), developed by Xing
Technology Corporation ("Xing") is the first commercially available
low-cost solution for world-wide and local network delivery of live
and on-demand video+audio. The National Broadcasting Company (NBC)
has broadly deployed XDMA for broadcast delivery of financial news
programming to subscribers in the U.S and Europe. New applications
are being developed with XDMA for distance learning, corporate
communications, news delivery and computer based training in
corporate, educational, government and health care markets, employing
wide area, local area and ISDN networks.
How XDMA Differs from other Video Networks
Existing "on-demand" multimedia (video) network architectures are
based on tightly coupled point-to-point client-server communication,
which result in 4 major limitations:
1. significant interaction is required between client and
server for flow control,
requiring complex server programming and signficant
data overhead (on
the order of 25% - 50%);
2. servers are not designed to deliver the same streams
simultaneously
to multiple users, making "live" delivery to multiple
users impractical;
3. LAN-based server architectures are not designed to operate
(and generally
don't work well) over wide area networks; and
4. communication protocols employed are proprietary, and do
not directly support the
TCP/IP international standard
XDMA represents a significantly different multimedia network
architecture, based on the concept of "streaming media". This
architecture supports both "on-demand" as well as "live" It video and
audio delivery which does not require close coupling between the
client and server. It easily supports "broadcasting" or
"multicasting" of live or on-demand content to multiple simultaneous
users over local as well as wide area networks. The benefits of XDMA
are reduced network component complexity, significantly increased
network flexibility, and significantly reduced network overhead.
Moreover, Xing's approach is built around international
standards-based components - Unix and (in 3rd quarter 1995) Windows NT
servers, TCP-IP connections, MPEG video and audio compression, and
HTTP-HTML client server communication. This allows better economies
in implementation and easy integration into existing communication
networks.
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