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Tuning of downstream rates

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Weaver:
See attached pic captured from clueless.aa.net.uk. This shows Netflix downloading a load of programmes and at 03:00 the downstream rate fraction was changed from 96% to 98%.

Weaver:
After 03:00, the top green lines which represent downstream IP PDU rate are at

#1 2.6 Mbps
#2 2.4 Mbps, dipping to 2.2 Mbps occasionally
#3 2.5 Mbps
#4 2.5 Mbps

Important: note the logarithmic vertical scale.

I think the uppermost horizontal dark grey straight line represent AA’s opinion of the current maximum line rate, as IP PDU rate, obtained by receiving events from BT and then down rated by multiplication by some fudge factor that AA has decided upon. It can change dynamically, when modems resynch, but there was no example of such here. It appears that it does not however include my choice of maximum rate fraction, so it is considered a property of the line rather than something that is my choice of how hard to drive it. Indeed you see no shift in the horizontal grey line at 03:00 when I changed my factional rate.

Immediately below that, the highest visible grey dotted line is, I think, ~2.154 Mbps = 1 Mbps * 101/3 seeing as that is the logarithmic spacing between the horizontal dotted lines.

kitz:

--- Quote ---Netflix IP PDU rate can be up and down, dropping as low as 6 Mbps then up to 8 or 9 Mbps and basically all over the place sometimes so don’t know what they are up
--- End quote ---


Apols if I've misunderstood, but isn't that the nature of streaming?   It doesn't just download the whole movie at once using one stream taking all your bandwidth and then its finished. 
It's continually opening up new connections to get the next chunk of data.  The more available bandwidth you have, the more the apparent it will be how spiky the stream actually is.

There's some examples on the main site I did years ago, but I'll post some of them in this thread so you can see typical streaming behaviour.

Streaming via Airplay


Streaming HDTV


Streaming iplayer to PC



On the last one in particular you can see how the data is being received in segments at different speeds.

Weaver:
I was not doing streaming, but doing flat-out downloads.

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