[asterisk-biz] Big PBX

[Trixter aka Bret McDanel]

On 2/8/07, Chris Icide <chris at netgeeks.net> wrote:
>
> Steve Totaro wrote:
> >>
> > How does average call length have anything to do with number of
> > concurrent calls?
> >
> Average call length doesn't affect concurrent calls directly, but does
> affect the number of concurrent calls when you are trying to relate
> estimated concurrent calls from total number of users.  However, I
> suspect you already knew the answer to this question....


Since its not clear I will also add call setup/teardown is generally more
expensive than just bridging media.  As such really low ALOCs can drive load
up higher than longer ones for the same number of concurrent calls, which
affects the overall number of channels you can process, effectively lowering
the concurrent call capacity of a given box.

Load balancing like with ser/openser can distribute this load, preserving
higher channel counts on an individual box, and your total capacity as a
hive.  One of the advantages of seperating signalling from media,
centralized routing and billing but distributed load across multiple boxes
:)

I am still wondering about the original 60,000 user claim, that can be
revealed but the user base doesnt allow for concurrent calls per box to be
revealed?

Anyway, even if its 200 calls per box as an average that still requires 30
boxes to accomplish a 1:10 use ratio at any given moment (not counting hot
spares for spikes in load, failures, etc).  Users vary greatly in phone
usage, if its 60,000 "grandmas" who barely make calls you might see a 1:100
or even less call ratio, if its a telemarketer doing multiple concurrent
calls it would be far worse perhaps upside down.  "grandma" and a
telemarketer are both 1 user each.  60,000 users without quantification of
the user type is in my opinion a meaningless number.




-- 
Trixter http://www.0xdecafbad.com     Bret McDanel
Belfast +44 28 9099 6461        US +1 516 687 5200
http://www.trxtel.com the VoIP provider that pays you!
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