Thursday, October 29, 2009

The great carrier pigeon test

Last night's HungryBeast had a segment in which a carrier pigeon was pitted against an ADSL connection and a car to transfer a data file. Thanks to itNews for alerting me to the segment.

The show recreated a test performed first in South Africa. It was in response to a comment in Parliament by Kevin Rudd that; "If the Liberals had their way Australians would be left using carrier pigeons for the future rather than accessing an internationally competitive broadband network." The challenge was to see which was faster - the carrier pigeon or the internet at transferring a file of a 700 MB movie 132km from Tarana to Prospect.

The results were the pigeon in 0ne hour and five minutes, the car clocked a respectable 2 hours and ten minutes and the internet advised the upload would take between "four and nine hours" but the net cut out twice "the second time for good".

The conclusion they reached was "So Prime Minister, maybe you should think twice before dishing carrier pigeons because if you live in regional Australia and need to send large files ANYTHING is better than the Internet."

Good example of how relatively slow broadband speeds are in regional Australia - but that actually was the PMs point. He wasn't dishing carrier pigeons - he was dishing the Liberals for selling out Australians on the prospect of better broadband.


So that's the policy analysis. But what about the test. Did this real life demonstration tell us anything?

Well let's first understand the internet connection. Ee don't get told much about the internet connection being used - except the claim that at the Tarana end the internet conection is the same as used by "90% of the population" but at the Prospect end there is footage of a laptop having a dongle installed...that is we don't know enough about both ends of the internet link.

In the course of the test we are told "the internet crashed twice". Presumably that was the connection, and not the whole internet. But we don't know the cause. It could have been any of the links involved (and this communication would have been going to the local Telstra exchange, then to an exchange in Sysdney, perhaps through two more in Sydney, before heading back out to Prospect exchange (if an ADSL link was used) then another line. Of course, being the net it is entirely possible packets were being routed through Mongolia. In fact the most likely cause of the "crash" was settings in either computer that couldn't handle a single large file transfer at slow speed (i.e. a time out action at the browser or other application not the internet connections).

But we are told the internet connection advised it would take 4 to 9 hours for a 700 MB transfer. Let's just do the sums...

MB700 MB is 5600000 kbits
4 Hours is 14400 Seconds a transfer rate of 388 kbit/s
9 Hours is 32400 Seconds a transfer rate of 172 kbit/s

But this calculation doesn't allow for the IP overhead added to convert the 700 MB to packets etc.

Meanwhile a car travelling 123 kms without knowing the route. Let's assume the 123 is the hypotenuse of a right angled isoceles triangle and that the road route is along the other two sides. That gives the total distance as 123 times the square route of 2, about 174 kms. I usually allow an average of 80 kms/hour for a mixed country city drive like that. Estimated time 2.175 hours, so the two hours and ten minutes is reasonable.

The evere reliable Wikipaedia suggests the average flying speed of a homing pigeon "over moderate distances is around 48 km/h, but speeds of up to 95 km/h have been observed." Either it was a very fast pigeon, or (more likely) it had a very good following wind to cover 123km in 1 hour 5 minutes (that would be 113 km/h).

The physical test has therefore not demonstrated much more than could have been worked out with a pencil and paper (or a spreadsheet...). The test is setting up a stupi example by focussing on the transfer of a 700MB file, and has chosen a sufficiently short distance to suit the purposes. Over a longer distance the internet transfer doesn't take any more time, while the other two do. The pigeon can't go as far as the car and the car is limited to the land of the continent.

Its is a pity that people ned to resort to such stupid exercises to demonstrate what we by now know...the old standard 256 Kbps (or a 512 Kbps as offered under the Australian Broadband Guarantee) doesn't cut it. And our reference point needs to be what we need to start building now to have in five to ten years.

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