[AG-TECH] Single vs multiple machine node?

Jason Bell j.bell at cqu.edu.au
Mon Mar 24 18:26:07 CDT 2008

G'day Dio


Please note that the reported usage I have stated is for using "Mpeg4"
and "DV" Streams.  If you were to use basic h261 streams, then streaming
8 separate streams could be done quite easily.


There are a couple of reasons to either use multiple machines or a
single machine:



Single Node - Display, Capture and Audio all in one

*         Less machines to configure;


*         May struggle to run very large AG sessions, though with the
new Quad core CPU's, this may be less of an issue;


*         May not have the power to use many capture devices, or
expansion slots to fit all capture cards;


*         May not have the power for H264, Mpeg4, DV and HDV encoding
and decoding, though as the results I forwarded recently, a new Quad
Core system does manage quite well;


o    Though if you have any plans for streaming 8 h264/Mpeg4 streams,
then you will need more than 1 system.


*         Multiple "vic's" applications cause difficulties - probably
the biggest issue;



*         Provides more computational power and computer resources to
run very large sessions;


*         More computers to configure and manage;



In my opinion, the computational power issues are becoming less and less
of an issue with the new quad core systems, unless you are wanting to
transmit extremely large number of "newer" codec video streams.   


For me personally, I think one of the biggest issues is that if you plan
on sending 8 video streams, and vic can only transmitting one video
stream (video producer) at a time, then you would need to have open 8
instances of vic open to find each of your video transmissions.
Whereas, on a multi-node configuration, you could have all the capturing
done on one machine and on the other, simply have a consumer process
which can see all 8 streams that your are transmitting and everyone
else's at the same time.  For simplicity, particularly for non AG users,
this makes the system a lot easier to use.  Obviously, you could manage
to setup some type of virtual system on a single machine and have the
same effect, but this is a lot more difficult to setup and manage.


Anyway, I hope my comments are useful.






-----Original Message-----
From: Dioselin Gonzalez [mailto:dioselin at gmail.com] 
Sent: Tuesday, 25 March 2008 06:50 AM
To: ag-tech at mcs.anl.gov
Subject: [AG-TECH] Single vs multiple machine node?


Hello (and greetings to all the people with whom I have worked in the


In building our nodes I wanted to ask the community your

thoughts/suggestions/experiences on having a single machine node.  We

wonder if having a quad-core machine (instead of 3 separate audio,

video and display ones) will be enough for sessions with many

attendees, streaming MPEG4 and running shared applications.  Jason

Bell reported CPU usage of 40% with 4 video streams


we are planning to send up to 8 video streams.


I'd appreciate your recommendations.  Thanks much!






Dioselin Gonzalez (SL: Chica Digital)

Research scientist

Louisiana Immersive Technologies Enterprise




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