[AG-TECH] [AG-USERS] Do I still need 3 servers in this day andage?

Jason Bell j.bell at cqu.edu.au
Wed Jan 21 19:51:04 CST 2009


G'day Les, Todd and all

I have given a number of presentations on Room design for the Access Grid and one of the topics I discuss is the use of single vs multiple computer AG node.

See http://www.arcs.org.au/support/training/video-collaboration-workshop/files/Design_Consisderations_for_Room_Based_Video_Collaboration.ppt for presentation.

Anyway, the section on computers is as follows:

Considerations for multi-computer capable software, such as Access Grid

*	Single Node – Display, Capture and Audio all in one
	-	Less machines to configure
	-	May struggle to run very large AG sessions
	-	May not have the power to use many capture devices
	-	May not have the power for DV and HDV encoding and decoding
	-	Multiple “vic’s” cause user difficulties

*	Multi-Node – Display Machine, Audio Machine and Capture Machine
	-	Provides more computational power and computer resources to run very large sessions
	-	More computers to configure and manage
	-	Improved Useability

With the advent of Dual, Quad and Multi-core CPU system on the market, in my opinion nullifies the computational reasons for a multi-computer AG node system.  That being said, usability it becoming more of a reason to have a multi-node setup.  Fore example, for each video stream you are wanting to "transmit", you will need a separate video services [instances of vic - there is a reason why this is a good thing] (whether it is a video service or video producer service), and therefore you can have up to 4 "vic" processes running on a single computer based AG node, in which you will need to look at each application to find each all of your video streams  [this isn't that user-friendly for non-AG users].  One advantages of using 2 or more computers, is that all of the video streams are being transmitted by one computer [commonly known as capture machine], and therefore a video consumer process only need to be run on the display mean...  What this means in simply term that all video streams, both locally and externally can be seen on the one application.  I find this to be extremely important for new users, as it is less confusing and simpler to use.

Another usability item that I have been finding lately, it that it is becoming for common for an AG-Node to employ a "presentation" computer [generally single screen] that has the AG software install on it as well, thus enabling screen streaming (say using VPCScreen) and shared applications.

I hope you find this information useful.

Regards,
Jason.

-----Original Message-----
From: Todd Zimmerman [mailto:todd.zimmerman at ubc.ca] 
Sent: Thursday, 15 January 2009 08:04 AM
To: Les Rhoda
Cc: ag-tech; ag-users
Subject: Re: [AG-TECH] [AG-USERS] Do I still need 3 servers in this day andage?

Hey Les,

I've cc'd this to AG-Tech also (its the more active list).


On Wed, 2009-01-14 at 16:29 -0500, Les Rhoda wrote:
> Hello all,
> 
> I work in Video Services at the University of Maine in Orono.
> 
> I have been tasked with constructing a quote for building an Access Grid node. It will be a small node, not even using projectors or anything fancy, just a small room that can act as a hub for some research teams to collaborate on.
> 
> I have scoured the net for hours trying to suss what the best and most economical way to build the node would be. I've researched all of the capture cards, cams, etc but I still have one burning question: do we reall need 3 boxes to process and
> serve, or can we pack it into one so long as we do not need multiple video input and display cards (which would require too many slots?
> 
> Any suggestions are immensely appreciated. I'm under a deadline for grant money and since I'm new to this job there is a lot riding on this (especially given the economy, etc :)
> 
> 

Using multiple computers is definitely not required - but provides
additional configuration options and abilities.  If you have enough
slots in a single box etc, I'd try one - you can always add another.  

Here's a blurb from a doc I'm just preparing:

I would say, in general, any reasonably new computer will have the
processing capability and memory to handle the load required for basic
collaboration needs. The one caveat to this, however, is that the
computational requirements for encoding and/or decoding multiple
MPEG4/H.264 streams has not yet been determined - so if you are going to
be using higher def video, your mileage may vary.  

The more important options are related to the number of
capture/display/audio cards, and the number and configuration of slots
available within the computer(s).  

For capture, there are a few different options. First, you can select
multiple reasonably priced analog capture cards (such as the Hauppage
Impact VCB) – or a single card that offers multiple capture capabilities
(Osprey 440).


For display, almost all new display cards offer dual output. If more
outputs are required, you should be able to just add an additional
display card; however you should definitely do some research before
purchasing multiple cards to confirm the configuration will work with
your operating system. 


For audio, depending on the quality of the typical 'on-board' audio
provided as part of the motherboard, you may want to add a reasonably
priced stand alone audio card. There have been sites that reported poor
quality (buzzing/noisy connections) when using on-board audio. However,
since collaboration usually doesn't involve a wide frequency range (like
cd quality audio) or require surround sound etc, and some of
collaboration software (RAT Audio Tool specifically) may not work well
with the more advanced cards, your best bet is a standard issue, medium
to low end audio card. 


Hope this helps.

Todd

-- 
Collaboration & Visualization Specialist
UBC Okanagan - http://web.ubc.ca/okanagan
WestGrid - www.westgrid.ca
Ph. 250-807-9979
Todd Zimmerman - todd.zimmerman at ubc.ca


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