Re: Telkom marketing at it again?

No one seems to have addressed the first error: -

> * What does kbps mean?
> Kilobytes per second.

No, it doesn't. It means kilobits per second. Bits, not bytes.

As to a realistic time: - 

Assuming that you get the maximum possible theoretical performance out of an ADSL line, which is typically around 87% [1]  of its capacity, we have:

Effective maximum line speed = 384 * 0.87 = 334 kbps = 334,000 bps (~= 42 kBps)

3 MB file = 3 * 1024 * 1024 * 8 = 25,165,824 bits

25,165,824 bits / 326,000 bps = 75 seconds.

That's "a little over one minute", if you're feeling generous. Realistically, since one seldom achieves maximum theoretical performance, you may well find that it takes several minutes to download the file. While it's impossible in practice to predict the actual speed on a contended consumer ADSL service, what you can say is that it will never take _less_ than 75 seconds on a 384 kbps ADSL line.

More interesting, perhaps, is Telkom's assumption that one is downloading MP3 music files. From where? Limewire for the typical kiddie?

Note that both "1000" and "1024" are used in the sums above, in the appropriate places, for speeds and sizes respectively.

[1] That arbitrary figure of 100 - 87 = 13% is what I remember from way back when I actually did the sums - and the online tests to confirm - the overhead taken up by the ATM framing, etc. Note that there is also the IP framing overhead to take into account. ( 20 bytes per packet + options, if any)

Cheers.

Kind regards,

William Stucke
ICASA Councillor
011-566-3009

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Roland Giesler
Sent: 17 March 2011 11:34 AM
To: IOZ
Subject: [IOZ] Telkom marketing at it again?

Just received a pamphlet in the mail from Telkom touting their new
"Simple" bundle.  (Note: not totally a bad offering!)

On it is a FAQ and the first question reads:

* What does kbps mean?
Kilobytes per second. This is the speed at which your line is
downloading the information from and uploading the information to the
internet. For instance, at 384kbps, a 3MB file, which is more or less
the size of your average music file, would probably take a little over
30 second to download

The problem, of course, is that the Hoi Polloi out there, have no idea
that it will actually take 7 minutes to download a 3MB file at
386kbps, not "just over 30 seconds".

This may not be a deal breaker, but Telkom (and Vodacom, MTN in the
past) have worked so hard to mislead South Africans that what they
offer is broadband instead of naming it thinband, that this just rubs
me up the wrong way completely.  And millions of people have received
this and so the darkness continues.

Would this be something that can be taken up by some industry body
like ISPA or does this fall in the ASA's jurisdiction.

regards

Roland Giesler

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