# A question of maths?

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A bandwidth report claims at no time within a 24 hour period the
bandwidth for a server exceeded 56 K bits p/s, and mainly remained
around 15 k bits p/s.

However, an http log file reports requests for 5gB of data in 24
hours.

This doesn't add up to me:

5 gB over 24 hours =

5 x 8 g bits over 24 hours

40 giga bits over 24 hours ==

40 giga bits over 86,400 seconds =

40 x 1024 mega bits over 86,400 seconds =

485 k  bits per second (averaged out)

While 15k bits per second =

1.875 K bytes per second =

162,000 k bytes over 24 hours =

158.2 mB per day

Even at 56k bits p/s that will not realise even 600 mB in a day (56/8
* 86,400 == 604,800 k bytes (590.6 mB) per 24 hours)

A very large discrepancy to the 5120 mB per day reported.

Am I being dense? Can anyone explain this to me.

Matt

## Re: A question of maths?

Matt Probert scribed:

Missing decimal...it 1 point 024, so

40 x 1.024 megabits = 40 x 1,024,000 bits

= 11.85 bps.

You're not being dense. You simply missed the point...decimal point, that
is. :-)
--
Ed Jay (remove 'M' to respond by email)

## Re: A question of maths?

Ay?

A gigabyte is 1024 megabytes, surely?

eg: 1 gb == 1024 mB (40 gigabits == 40 x 1024 megabits)

I still remain confused.

Matt

--
Woe to him that willfully innovates, while ignorant of the constant.
http://www.probertencyclopaedia.com

## Re: A question of maths?

Ed Jay wrote:

No I think Mr. Probert's math is good.  1 Gb = 1024 Mb.

I'd bet that the server logs the size of the requested file without regard to
the status of the TCP connection.  In other words, If you have a single 5 GB
file being served, and I start to download it, it's counted in the log even if
I cancel the download before it completes.  Of course, not knowing the
environment, this is nothing more than a guess.  It's probably just as likely
that the data rate statistics are garbage.