[Asterisk-Users] OT: Calculating Bandwith

[Stephen Davies]

On Wed, 7 Jan 2004, calvis wrote:

> 
> I am trying to calculate bandwidth needs.  Is 1 T1 Line able to provide
> 488.5 Gigabytes of traffic for 1 month based on a 30 day week?   I did my
> calculation as follows:
> 
> 1.544 mps * number of seconds in a minute(60) * number of minutes in a hour
> (60) * number of hours in a day(24) * number of days in a month(30) =
> 4002048 megabits / 1024 = (3908.25 gigabits)  / 8 = (488.53125 gigabytes) of
> bandwidth for a T1 Line.
> 
> Please correct me if I am wrong.
> 
> Thanks,
> 
> Charles

Theoretically your calculation is fine - in fact the line will do that
much in each direction, so twice as much in total.

In practice for almost all real-world uses, you will find that user
experience is intolerably bad before you get anythere near that
theoretical capacity.

This is because of bursty use of the line, and because of TCP's
behaviour under contention.  In my experience you should expect to get
say 25-40% of the theoretical capacity per month with acceptable
performance.

Obviously it depends on how you are going to use the line.

Regards,
Steve Davies