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Standard User RobCW
(newbie) Thu 17-May-12 10:18:28
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Re: Upload Speeds Doubled, Downloads didn't ? FTTC


[re: adebov] [link to this post]
 
Thanks. It is very strange - I was trying the mirror.nl.leaseweb.net site too last night and getting pretty much the same download file speed as TBB downloads (around 10 to 15 Mbps). Tried again this morning and now getting around 45-50 Mbps single threaded. Although TBB is still no faster.

Unless its the various servers not being able to handle at peak times I can only agree it must be BT doing something.
Standard User davestubbs
(member) Fri 18-May-12 12:05:11
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Re: Upload Speeds Doubled, Downloads didn't ? FTTC


[re: philippercival] [link to this post]
 
Sounds a little more promising, I'm still waiting for Web Tapestry to come back to me at the moment so no progress on mine still being stuck at 40Mbps.

Interestingly, Web Tapestry are only interested in the speed the bt speedchecker gives, though at least that does tell them the line should be capable of up to 70Mbps and as I'm only getting 40 I hope that's enough to generate some activity.....!
Standard User philippercival
(experienced) Fri 18-May-12 13:17:20
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Re: Upload Speeds Doubled, Downloads didn't ? FTTC


[re: davestubbs] [link to this post]
 
My Speeds have definietely improved, after a fix that I think ENTA has pushed out to all its nodes by now, though I am not sure what the fix actually was.

My BT Speedtest gives me a profile of 64.42 down and 20 Up.

The BT speed checker has never come closer than 59Mbps down, though speedtest.net has shown up to 60.63Mbps.

Interestingly when I was talking to my ISP support desk, they told me something that I think rather makes a mockery of all this and I had not read before signing up and still can find no reference to on their site. Because I am on the family 30 product, BT applies some sort of limiter to me from 8:00am to 8:00pm. From 8:00pm to midnight my traffic is a top priority and so I should achieve my speeds (this was when the ISP wanted me to do tests). From Midnight to 8:00am it is a free for all for both business and home users.

So as far as I can see, 80/20 means

My line length etc will reduce max possible to 64/20
This is not quite actually achievable at the best of times.
Depending on what sort of contract you have you probably further limited according to your type of contract. (In my case I can only achieve the Max for 4 hours a day).

Even if I could find where my terms were listed I think this is a very similar mis-selling argument to the "Up to 8 mbps" that has being going on for ages and something has been done about.

Having said all that FTTC is blindingly fast and I am delighted to be rid of my 3.4mbps at best rate. I do suspect that the network (BT/openreach) may have some capacity issues due to the changeover to FTTC.


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Standard User RobCW
(newbie) Fri 18-May-12 14:13:38
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Re: Upload Speeds Doubled, Downloads didn't ? FTTC


[re: adebov] [link to this post]
 
Found this forum while searching for more information on this issue:

http://www.skyuser.co.uk/forum/sky-broadband-fibre-h...

Seems like they are talking about similar issues and getting profile reset resolves the problem? Thoughts? Anyone had this done?
Standard User adebov
(eat-sleep-adslguide) Fri 18-May-12 18:54:57
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Re: Upload Speeds Doubled, Downloads didn't ? FTTC


[re: RobCW] [link to this post]
 
Profile issues will be a different problem and not related to low speed single-thread whilst still getting high multi-thread downloads.

I check my IP profile (by doing a BT speedtest) quite regularly and it's always 77.4Mbps (or 77.39Mbps, or whatever equates to an 80Mbps sync).
It's never shifted from that level.

Some ISPs (certainly on old ADSL products) also have their own profiling system (the IP profile advised after a BT speedtest is your IP profile on the BT Wholesale system). If records are not kept up to date, this ISP profile could end up being lower [than the BTW one] and limit the speed, but this will limit total speed and not just single-thread speeds.

We still don't know the real reason, or why single thread downloads are so slow for only a fraction of FTTC customers but with the limited amount of information it does look like a single-thread throttle.
Quite why Speedtest.net reports around 77Mbps down (and 17Mbps up), whilst the TBB tester reports as low as 6Mbps down and rarely gives upload results higher than 7Mbps, is a bit of a mystery.

The mystery deepens when I can run a TBB speedtest on my XP (2002 version, XP-Pro, SP3) laptop and get 50-60Mbps down & 16Mbps up, yet immediately switching back to my W7 desktop gives TBB download test results around 30Mbps (at best) and back to around 6-7Mbps upload.

I think we're seeing two things (which are necessarily related): -
1. Some quirky difference between Java for XP 32-bit and Java for W7 64-bit, which affects the TBB speedtester (no other differences, both machines have exactly the same AV software and both wired Ethernet into the same gigabit switch - if anything; the W7 desktop is the more powerful of the two machines - double the RAM and a 64-bit CPU, with a 64-bit OS).
2. Some odd BT single thread throttle (because low single thread downloads are not confined to TBB).

Ade

vDSL2 FTTC Infinity with BT
DL Sync 80Mbps
UL Sync 20Mbps
Standard User qasdfdsaq
(member) Fri 18-May-12 19:35:03
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Re: Upload Speeds Doubled, Downloads didn't ? FTTC


[re: adebov] [link to this post]
 
The whole single thread throttle idea is, in my opinion, wildly off the mark. There's no reason why BT would be throttling single threaded downloads, or any ISP for that matter. The vast majority - including my observations of BT - throttle down to a total speed per customer or per protocol, never per (TCP) connection. Except, maybe when traffic shaping malfunctions.

There are plenty, plenty of other reasons that adequately explain the slowness, including funky interactions between the server, connections between you and the server, as well as the TCP/IP stack of your operating system as you've yourself gathered. There is no single reason and probably the reason for the different testing sources will be different.

All of the reports I've seen so far involve using known bad or unreliable sources, and hence remain inconclusive. The TBB speedtester and file downloads are included in these.

Try these speedtests if you want something known to work (for me) under Windows 7:

http://mcslhr.visualware.com/myspeed/myspeed_line_ap... (single connection, high port number)
http://mcslhr.visualware.com/myspeed/myspeed_line_ca... (4 connections)
http://mcslhr.visualware.com/myspeed/mycapacity_50mb... (connectionless UDP)

My results, for reference are 51.3/16.6 on the first test and 56.2/16.6 on the second. My IP profile (well not actually, my self-enforced QoS limiter) is equivalent to about 58.5mbps.

Note interestingly I did get a result of 13.9/16.6 once too, which suggests it got inadvertently caught by traffic shaping at one point.or that TCP window scaling broke. Repeating the test a few times gave the 51.3 result.

Edited by qasdfdsaq (Fri 18-May-12 19:42:12)

Standard User adebov
(eat-sleep-adslguide) Fri 18-May-12 21:10:36
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Re: Upload Speeds Doubled, Downloads didn't ? FTTC


[re: qasdfdsaq] [link to this post]
 
Unlike you, I'm getting a massive 30Mbps difference between the 1st (single-thread) and 2nd (four thread) testers...

1st test (single thread): -
Download Speed: 44278 kbps
Upload Speed: 18256 kbps
Speed Consistency: 83 %
Round Trip Time: 16 ms
Max Delay: 24 ms
Average Delay: 1 ms
Bandwidth: 71697 kbps
Forced Idle: 56 %
Route Concurrency: 1.6
Test Type: s / s
Round Trip Time Consistency: 94 %

The download speed of this first test is almost exactly the same as the TBB tester
My Broadband Speed Test

2nd test (four threads): -
Download Speed: 74453 kbps
Upload Speed: 18431 kbps
Speed Consistency: 97 %
Round Trip Time: 15 ms
Max Delay: 34 ms
Average Delay: 1 ms
Bandwidth: 76590 kbps
Forced Idle: 62 %
Route Concurrency: 1
Test Type: s / s
Round Trip Time Consistency: 88 %


3rd test: -
Indicates line capacity (with zero % data loss) of 74.1Mbps (based on a target of 75.8Mbps).
When it tries for a target of 80Mbps it gets 74.2Mbps (a quoted data loss of 5.2%).
So, clearly, my line capacity is 74.1Mbps

So, obviously something is limiting the single thread download speed and it's either ISP or wholesale related, or something on the [not particularly tweakable] Windows 7 OS. Or it's something quirky with Java running on a 64-bit OS.

Interestingly; the 1st test results pages says
MSDL01: The download speed is too low for the latency/bandwidth of the connection

This means that download throughput has been recorded lower than the attainable speed for the connection being tested and this degradation is not accounted for by the latency of the connection. This indicates that the connection has data flow interference through congestion or regulation problems.

A high TCP Max Delay and/or a low Data Flow QoS will also confirm any occurrence of data flow quality problems.
(my bold).

Ade

vDSL2 FTTC Infinity with BT
DL Sync 80Mbps
UL Sync 20Mbps
Standard User qasdfdsaq
(member) Fri 18-May-12 21:39:22
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Re: Upload Speeds Doubled, Downloads didn't ? FTTC


[re: adebov] [link to this post]
 
Could just be congestion.

I've just repeated the first test a few times, with my QoS limiter off (so just IP profile of ~71.6)

In Firefox, I got 13.7 down, 43.1 down, and 53.6 down on three consecutive runs, in Chrome I got 55.0/18.6. The former appear to have been erroneously traffic shaped or badly managed by Windows.

In the second test I got 68.8/18.6, so yes, a slightly bigger difference there, but still not huge. Thinkbroadband gave me 44.5/5.6

If I download a single file from my server I get a full 71.2mbps throughput showing in DU Meter and 8.2MB/sec in Chrome's UI (ftp://test:[email protected]/) - so no problem with single connection there.

So while I do see a 15mbps reduction on the MCS test server - it could just be server or path congestion. Give my server a try (just don't all go at it at once), see if you get the same difference - I don't, suggesting it's not single-connection throttle.

Note my Windows networking setup is *slightly* tweaked, but I also have a buggy network card driver. Also note my FTP server has a custom socket buffer setting optimized for throughput. Lots of it.

Incidentally from that same server I get 12.7 on the single-threaded test and 53.2. Now I know there's zero traffic shaping or throttling whatsoever on that connection.

Edited by qasdfdsaq (Fri 18-May-12 21:54:47)

Standard User adebov
(eat-sleep-adslguide) Fri 18-May-12 21:59:41
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Re: Upload Speeds Doubled, Downloads didn't ? FTTC


[re: qasdfdsaq] [link to this post]
 
In reply to a post by qasdfdsaq:
Could just be congestion.

I've just repeated the first test a few times, with my QoS limiter off (so just IP profile of ~71.6)


Well there does seem to be a little congestion (but given it's 9:50pm on Friday that's probably to be expected).

I've spent some time disabling many of W7's auto-tuning gibberish (which clearly doesn't work too well for fast connections) and have now got 63436 kbps from your single thread recommended tester (an improvement of almost 20Mbps).
TBB is still all over the place, but with my new tweaked settings I've got my first TBB result over 45Mbps. Most TBB results are coming back in the mid 50's (first time I've managed to get over 45Mbps) and the highest is 63.2Mbps.
My Broadband Speed Test

Even TBB's test files are hitting over 50Mbps in single-thread mode (significantly better than the 6-16Mbps I'd been getting previously).

So you were quite right and we can now blame Microsoft's poor auto-tuning and not BT (which still doesn't explain why so few are affected - I'd have thought most W7 users still have all the default auto-tuning settings).

If anyone else feels confident enough, this site gives a very good explanation AND their recommended settings (to override Windows and keep it overridden).

Windows 7 should come with a warning sticker smile

EDIT: Still only 7Mbps upload from the TBB tester, but that appears to be another issue (possibly also OS related, or Java quirks, as I can get well over twice that with XP).

Ade

vDSL2 FTTC Infinity with BT
DL Sync 80Mbps
UL Sync 20Mbps

Edited by adebov (Fri 18-May-12 22:01:57)

Standard User jchamier
(knowledge is power) Fri 18-May-12 22:54:41
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Re: Upload Speeds Doubled, Downloads didn't ? FTTC


[re: adebov] [link to this post]
 
In reply to a post by adebov:
If anyone else feels confident enough, this site gives a very good explanation AND their recommended settings (to override Windows and keep it overridden).


Fascinating.

I wonder if this is related to the asymetric nature. I don't see problems with self installed (from MSDN disc) Win7 in the office on a test network with a Dell server and a Core i3 desktop. I get gigabit speeds.

It could be down to home routers, or ISP routers affecting things and Win7's adjustment not "adjusting" properly - but I read that the Vista network stack was rewritten from XP and earlier - and followed the ideals in the Unix/Linux stacks.

Out of interest what make of NIC do you have/use? I've got Broadcom at home (on a Dell XPS desktop) but Intel at work.

Still good news for you smile

James - be* pro - 16.8 or 17.2mbps BQM
No FTTC cabinet yet (originally Mar 2011) THFB PCP 5 - hope for 21st May to 1 June !
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