From: Dan Pisarski <[EMAIL PROTECTED]>
Subject: RE: bandwidth
A few small corrections here, someone stop me where I go wrong...
A single-line ISDN is 64kpbs, a dual is 128kpbs. DSL varies
widely...you'll have to check with your service provider. Obviously, 56k,
28.8k and 33.6k modems are what their number is...except 56k which is
really 52 (FCC laws prohibit it from being more). A T-1 line is 1.54mbps
(megabits...a thousand kilobits) and a T-3 is 92.4mbps (60 T1 lines).
Not 60, but 30 T1 lines, thus it is 46.2mbps.
So multiply your available bandwidth by 0.9 (90%) to give 10% to overhead
You can use different numbers here but I would recommend something higher
than 10%, probably 15 or 20% to get "real word performance." And that is if
there is no other traffic on that line - if you are using the same line to
bring stuff in, that is going to use up room. So say your company has a T1
- not only do you loose 15% to general performance problems and such, you
are probably using another 20% in internet traffic (outbound) and if you
hosting a web server, you are using even more (inbound). You need to look
at what part of the pipe is really available to you - it may be 50% of the
total bandwidth or less.
room, and then divide by the bandwidth allocated to each stream (say
20kbps)
Except what stream is using 20Kbps? That is a 28.8 stream - if your files
are encoded for higher bandwidth, you need to count on a higher cost (in
kbps) per stream.
to determine how many simultaneous streams you can have. So if you
have a 20kpbs stream, and a dual-ISDN line:
128kpbs x 0.9 = 115.2kpbs 115.2 / 20 = 5.76 = 5 simultaneous streams
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