The data
below should assist in estimating response
times during peak usage. When estimating
response times, one must also weigh external
factors such as network capacity, media,
network congestion due to other programs/
systems, etc.
Studies on the usage patterns of our current CD-ROM
course show that most users take the course in two
or more sessions, which are spread out over one day
to two weeks. Note that video and audio do not play
for the entire duration of the courseware. Assuming
however one user completes all modules in the course
in two hours, here is the estimated network bandwidth
usage for the different modes of video playback of
the HTML version of the courseware:
Internet login and logout: 8KB per session, independent
of playback mode.
High-Bitrate Video:
65MB total over two hours. Streaming rate for video
with audio is 220Kbps. Streaming rate for audio-only
events is 23Kbps.
Slideshow
with Audio: 25MB total
over two hours. Streaming rate
for video with audio is 23Kbps.
Streaming rate for audio-only
events is 23Kbps.
Text-and-Graphics:
10MB total over two hours.
The HIPAA Compliance course contains about 20 minutes
of video-with-audio and about 40 minutes of events
containing audio-only. The maximum throughput for any
given user will be 220Kbps. Over the two hours of courseware,
we estimate that the average throughput for users at
the highest bandwidth selection will be less than 9Kbps.
Lower bandwidth settings will have much lower maximum
and average throughputs.
The central content file server or web content server
for our HTML version of the courseware will be supported
on either a Windows platform or a UNIX/Linux platform.
Macintosh platforms will not be supported for the content
file or web server.
HCCS does not
normally make recommendations on specifications
for the centralized server hardware. However,
if a UNIX/Linix platform is used, running Apache
Web Server, a single 400MHz processor with 1GB
RAM should be sufficient for 200 concurrent users
using Text and Graphics mode or 200 Slide Show
Users. Similarly, if a Windows NT server is used
running IIS, a single 1GHz processor with 1GB
RAM should be sufficient for 200 concurrent users
using Text and Graphics mode or 200 Slide Show
Users. Note that the institution may choose to
use several smaller servers distributed throughout
the institution for content repositories. A distributed
content architecture may ease network congestion
over certain network segments.
For more information on rightsizing windows servers
for multimedia applications, please see the following
URL:
http://msdn2.microsoft.com/en-us/library/Aa904743(VS.80).aspx.
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