Webmaster forum - Bandwidth Calculation

Author

Bandwidth Calculation

John3478@gmail.com

2006-09-24, 6:58 pm

Any know how to calculate numbers of files per second can be download
for 5MB files?

For 10 megabit if I divided by 5, look's like it's only able to serve 2
files download in one second?

>From microsoft site, calculating bandwidth
https://www.microsoft.com/technet/p...5.mspx?mfr=true

For 5kb file
10-megabit Ethernet (Up to) 136 pages/seconds
100-megabit Ethernet (Up to) 1,360 pages/seconds

For 5MB file (Video, flash FLV)
10-megabit Ethernet (Up to) ??? files/seconds
100-megabit Ethernet (Up to) ??? files/seconds

Thank you in advance,
John

Brian Wakem

2006-09-24, 6:58 pm

John3478@XXXXXXXXXX wrote:

> Any know how to calculate numbers of files per second can be download
> for 5MB files?
>
> For 10 megabit if I divided by 5, look's like it's only able to serve 2
> files download in one second?

10,000,000 bits = 10M/1024/1024/8 = 1.192MB

So the answer is 0.238 5MB files per second.

--
Brian Wakem
Email: http://homepage.ntlworld.com/b.wakem/myemail.png

Andy Dingley

2006-09-24, 6:58 pm

John3478@XXXXXXXXXX wrote:

> Any know how to calculate numbers of files per second can be download
> for 5MB files?

Measure it. Anything else is guesswork.

You can calculate some upper limits for speed, but reality is so much
less than that (raw bandwidth is huge these days) and is so dependent
on things you can't easily study or measure, that these aren't much
help in determining practical estimates.

John3478@gmail.com

2006-09-24, 6:58 pm

Thank you for the input, now I know how to calculate my need

I want to find out how many files able to download at one time. In case
you want to know about it. Here the value that I come out with.

Hosting Provider : 10Mbit/s
User download speed : 100kbit/s
File to download : 5 MByte

Total file to download at one time using
above value : 100 files.

Brian Wakem wrote:
> John3478@XXXXXXXXXX wrote:
>
>
>
> 10,000,000 bits = 10M/1024/1024/8 = 1.192MB
>
> So the answer is 0.238 5MB files per second.
>
>
>
> --
> Brian Wakem
> Email: http://homepage.ntlworld.com/b.wakem/myemail.png

Toby Inkster

2006-09-24, 6:59 pm

John3478 wrote:

> Any know how to calculate numbers of files per second can be download
> for 5MB files?

Very few.

--
Toby A Inkster BSc (Hons) ARCS
Contact Me ~ http://tobyinkster.co.uk/contact

Jerry Stuckle

2006-09-24, 6:59 pm

John3478@XXXXXXXXXX wrote:
> Any know how to calculate numbers of files per second can be download
> for 5MB files?
>
> For 10 megabit if I divided by 5, look's like it's only able to serve 2
> files download in one second?
>
> https://www.microsoft.com/technet/p...5.mspx?mfr=true
>
> For 5kb file
> 10-megabit Ethernet (Up to) 136 pages/seconds
> 100-megabit Ethernet (Up to) 1,360 pages/seconds
>
> For 5MB file (Video, flash FLV)
> 10-megabit Ethernet (Up to) ??? files/seconds
> 100-megabit Ethernet (Up to) ??? files/seconds
>
> Thank you in advance,
> John
>

Impossible to calculate.

5MB file is 40 megabytes (8 bits/byte). So you would think that a 4MB
file could be downloaded in 4 seconds on a 10Megabit link.

But there's additional overhead. The data is sent in packets. The
packet size varies, but there is additional overhead associated with
each packet - around 36 bytes, IIRC (I'd have to look up the details).

Additionally, even in the data extra bits can be inserted as part of the
protocol. Normally there are few of these - but they can increase the
number of bits sent anywhere from 0 to about 10%.

Then each packet sent must be acknowledged. After so many packets are
sent, no more can be sent until some have been acknowledged. And of
course, the acknowledgment must come from the client - so it depends on
the time it takes for the packet to be sent, received by the client, an
ack returned and the ack received by the server. And if the ack isn't
returned before a preset timeout, the packet must be resent.

So, as you can see - there are a lot of variables which you cannot
control. But basically you'll be extremely lucky to get 1/2 the link speed.

And if the host and client have different link speeds, the slower of the
two (or the slowest link between the two) determines the maximum speed.

--
==================
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Jerry Stuckle
JDS Computer Training Corp.
jstucklex@attglobal.net
==================