FTTC speed thoughts

[Bill]

It's just occurred to me... on the BT speedtester I often see a message "16 threads!", could BT be using a multi-threaded download test?

I'm fairly sure that the Ookla based tests do (eg speedtest.net), and that the tbb one only uses a single thread. From odd comments in other forums istr that multi-threading will give faster downloads (especially on high speed links), and it also seems reasonable that most non-testing downloads a user performs will be single threaded.

It could explain what we're seeing... if it makes any sense???

[Rik]

I often see that, Bill and have wondered what it meant. What you say is plausible.

[.Griff.]

The Usenet download graph I posted yesterday was using 20 connections/threads and that suffered from the same erratic speed unfortunately.

[Rik]

There goes another good theory.

[.Griff.]

I might have stumbled upon something interesting.. Give me 2 minutes..

[.Griff.]

This could be purely coincidental but I thought I'd try downloading from Usenet again. Same NNTP provider, same 20 connections but this time I enabled SSL.

While not perfect the speeds were a lot more consistent and stable.

Not sure what to make of that?!?

[Rik]

That makes two of us. Would it have moved you to a different stream at their end?

[.Griff.]

That makes two of us. Would it have moved you to a different stream at their end?

I did change the NNTP server (to one that supported SSL) so may be why. Perhaps I just caught a "pocket" where everyone is cooking and/or sitting down to watch TV.

[Bill]

Not sure what to make of that?!?

Not even sure what it means!

but maybe the variations aren't purely network related...

[Rik]

Comms has been a black art since my first 300 baud modem. You know what you're seeing but you can never be sure where things are going pear-shaped. It might be worth doing a tracert at good and bad times - though ICMP traffic gets low priority so it can't prove anything, but it might give a pointer.

[.Griff.]

Not even sure what it means!

Secure Sockets Layer (Encryption)

[Glenn]

http://forums.thinkbroadband.com/bt/3649781-interpretation-of-bt-speedtester-results.html?page=27&sb=1 It appears to be faster using SSL in the past too.

[Steve]

Perhaps there is just less contention on SSL one uses port 80 and the other one uses 443.

[Bill]

The tbb one uses port 8095, don't know what the others use.

[Bill]

Think I'll knock the download tests on the head- apart from it getting boring, each BT/tbb pair of tests eats nearly 200MB out of my allowance!

But I've got enough data... the tbb test is consistently quite a lot slower than the BT one, shows signs of congestion even when the BT one doesn't, and at times when (from experience) I'm fairly sure my exchange isn't particularly busy. If my earlier ideas about the number of threads has any basis, my trust in the tbb tester is markedly less than it used to be. Although it could be a routing issue as well, and the upload speeds are still a touch anomalous.

I also did a ~6GB download from iTunes just before midday today- it came down at a steady 33-35Mbps. So I'm happier than I was about the connection, though VDSL still seems more vulnerable to congestion than ADSL.

The iTunes download was interesting... rather than a flat top, the trace showed a marked, and very regular, sawtooth pattern at the top. Investigating around showed that this was replicated on the disk activity trace... the files were being stored on an external HDD via Firewire 400, and it looked as though servicing the drive and interface was having an impact on the instantaneous download speed (obviously the monitor is looking at the Ethernet, not the VDSL signal). It's a 2.16GHz Core 2 Duo machine, so it would seem that fast internet connections need fast computers!

Worth bearing in mind I think, that the hardware can have an effect.

[Rik]

Indeed, Bill. 

[Bill]

Indeed, Bill. 

So when you get your FTTP connection you'll (reluctantly of course) have to think about getting a faster computer

[Rik]

I'll tell Sue you told me  had to. No problem.

[.Griff.]

I also did a ~6GB download from iTunes just before midday today- it came down at a steady 33-35Mbps.

Can you share the details of the file so I can try it myself?

[Bill]

It wasn't a single file, it was the Yellowstone TV series... 3 HD episodes at ~1.5GB each, and the SD ones at ~500MB each.

Oh, and d/ling the series will cost you £6.99

[.Griff.]

lol I'll give it a miss then.

[Rik]

It was a good series.

[Glenn]

It was missing Yogi and BooBoo though

[Rik]

[Bill]

Didn't see the original, but it would have been in SD anyway.

This way I can watch it in HD

I note that there's only 3 episodes though- Winter, Summer and Autumn. What happened to Spring?