FTTC serious slowdown evenings and weekends

I've just recently had BT Infinity installed. At first I was delighted with it (nearly 37 Mbps download), but over the past few weeks noticed a worrying pattern emerging. It seems that every evening and at weekends the speed drops significantly. For instance most of today and yesterday it's hovered around 3-4, apart from early this morning. When I check in the morning (7 am) the speed is always back at 34-37. I've tried replacing the HH3 with my own Netgear router and ran tests wire/wireless with the same result. Uploads are always rock solid at about 7-8.

Doing a bit of research I've come across various people mentioning congestion issues. I've no idea what technology is used here or where the congestion might occur (is it an issue at the local exchange) or more importantly what to do about it. I had a BT engineer around recently and he just checked the line and said everything was fine (which it was because he checked it at 2.00 on a Friday).

Any advice would be welcome.

Welcome to the forums .

Which exchange is it please? If you don't know, use this checker.

The engineer won't have been looking at through put speeds, just sync rates.

What results do you get from www.speedtester.bt.com on a wired connection ?

I'm on the Shrewsbury exchange

I just tried a bt speedtest wired, and it gave me a download speed of 0 (I'm guessing it's got some issues). I then tried the 'tap3' test (the one where you have you change your login) and it came out at 4Mbps. My ip profile is set to 38.71 Mbps. I tried it a few days ago when it was slow and the bt speedtest result more or less matched the speed I got wirelessly from speedtest.net, in this case around 7Mbps.

There was no reported congestion there on the last date I know of, but the latest report date is 11 March.

I've been getting exactly the same (I'm on the Banbury exchange).
Speed tests (no matter which speed test site I use) struggle to get above my old 4.5Mbps BE connection, yet as soon as we get outside of peak hours the speedtests are a rock-solid 37Mbps.

From August last year, through to a week or two ago, I used to get speed test results of 37Mbps irrespective of the time and day.

Going by many years experience (and regulars of these forums will have seen it many times before with the old ADSL products), there's little doubt in my mind it's either localised congestion (can't be national because the forums would be full of complaints) or BT are throttling web traffic on their Infinity product.
Or BT have a "bad boys" list and are throttling heavy (ish) downloaders.

My issue is definately not with my connection (sync'd at maximum speed and it only ever drops sync when I reboot the modem - it's easy to spot this with a large ISP like BT as your IP will most likely change when your modem re-syncs - between October last year and the begining of March this year, I had the same IP address).

If I set up a Usenet download it will go at maximum speed at any time of the day (even when speed testers give results of around 4Mbps for my 40Mbps connection).
Therefore it's unlikely to be congestion (if the networks - locally or nationally - were congested I wouldn't be getting full speed from Usenet).

Oddly enough it all started around the same time as BT started making 80Mbps connections available to new and existing customers (i.e. came out of any trial phase, and went into roll-out mode).

My money is on throttling.

EDIT: pings are rubbish too - just got 26ms to a server in Coventry (about 30 miles up the road and the one Speedtest/net selected as my closest server).
I normally get pings at (or just below) 10ms.

Edited by adebov (Sun 22-Apr-12 20:40:58)

I reckon BT Wholesale failed to anticipate the 80/20 takeup and the speed test servers aren't geared up for it.

As soon as a small amount of congestion appears on the WBC backhaul, which coped fine with 40/10, we all hit the speed testers. That worsens enormously the load on the backhaul, and also on the BT speed tester.

Result - mayhem!

Without speed testing the congestion may be manageable. Until we look at it using queuing theory.

Any idea how to distinguish deliberate throttling from congestion? I know BT throttle P2P at peak times but I've just tried going onto the thinkbroadband large file download section

http://www.thinkbroadband.com/download.html

And clicked on the 1GB file. It's offering up about 33 mins whereas yesterday morning it was about 2 mins. I can still watch iPlayer thank goodness, but it's worrying the speed has dropped so far.

Congestion should affect all protocols equally.

Throttling will just affect one or two things like torrents and newsgroups

hav bt said anythin bout this? im loking at them 2 as o2 are rubbish havin to use my fone to get web tonight

Ah ok. So if my download of the large 1GB test file is slow, then it's more likely to be congestion as it uses a different protocol to P2P, and BT are only throttling that? Is that right or am I wide of the mark there ?

Assuming it in congestion, is there anything I can do about it?

thanks for all the replies by the way.

In reply to a post by adebov:

I've been getting exactly the same (I'm on the Banbury exchange).

For what it's worth it seems fine down the road in Brackley but I'm with IDNet.

I would have thought deliberate throttling would come without an increase in the ping time.

Try the TBB 1GB download test file using a download manager (something like FreeDownloadManager .
Using a 12 split (i.e. splitting the file into 12 sections and downloading simultaneously) I'm getting a download speed of around 4558kB/s (around 36.5Mbps) - i.e. practically full speed.
If I download the same file using a single thread (e.g. downloading with IE) I'm getting a very bouncy download of between 6-14Mbps.

In my past experience (and I've been with some of the worst ISPs for congestion - Eclipse, Plusnet, ACE, Entanet) congestion has normally affected total available speed no matter how many segments/sections/threads are involved in the download.
I.E. A multi-thread Usenet download would also slow down when congestion is present.

Apart from deliberate throttling (although I'm sure someone will come along and correct me) I don't know of many issues which would cause a single thread to download significantly slower than a multi-thread.
I think we can eliminate PC and setup problems (as the issue corrects itself after peak hours have passed) - if you had MTU / Rwin / wireless / etc. issues surely the speeds would be low at all times (you wouldn't get 37Mbps downloads at 2am and 4Mbps downloads at 8pm if you had your MTU frame size set incorrectly).

It's possible any throttling (and it remains to be proven - either way) could be in place to prevent network overload caused by a sudden switch from 40/10 to 80/20 products.
It wouldn't be the first time an ISP has throttled some users, at peak times, to protect their network. Plusnet did (and most likely still do) this and Entanet had a very elaborate "throttling" system in place which kicked it (at varying levels of intensity) as their backbones started to overload.

Maybe the happy time is over and we're starting to wake up to the impossibility of providing a "real" unlimited product (at such high speeds) for £30 a month?

In reply to a post by thorice:

hav bt said anythin bout this?

I honestly wouldn't know who to call (or at least anyone I could get some sense out of).
The final step of the BT speedtester (it only goes to this if you get a rubbish result) suggests calling the ISP (which is, of course, BT) but I'd put money on there not being anything in the "script" at the Indian call-centre to deal with this.
And I certainly don't want BT to get wind of this and start mucking about with my profiles and capping speeds in an attempt to fix something which has nothing to do with profiles or connection speeds.

I'm not going to call BT because I don't want to spend the next week wasting my time rebooting routers and modems and re-installing Windows (the normal suggestions made by "help" lines, as it's bound to "be something your end" which is causing the problem).

Edited by adebov (Sun 22-Apr-12 21:42:59)

Just tried your suggestion and I'm getting 478KB/s which is still coming in at about 30 odd mins for the download, so it does look like a congestion issue.

I feel a little churlish complaining about low speeds as I could only previously get 1Mb before infinity, which was woeful. However, if I'm hovering around 4Mb in the evening, once a few people in my family start using the internet, it could make things like iPlayer unusable, which for £25 a month is pretty grim.

My fear is that something like this will never get resolved given it only happens when the people likely to be able to sort it (a competent engineer) aren't working. I'm also not sure I can face the prospect of phoning the general BT helpline given peoples horror stories on other forums.

Maybe I'll just have to become nocturnal

Congestion is most likely

What can you do? Not a lot usually

Well I'm sitting and waiting, in the hope it's temporary and caused by a sudden take-up of the 80/20 product (which is now available, with a few days lead time, for existing customers and new people can go straight onto it).

If any company can afford extra bandwidth, it's BT.
The danger is if people don't complain (and I'm certainly not going to call them) BT might think nobody has noticed and will try to get away with not paying for more capacity

Aren't BT obliged to provide a minimum download speed? I read somewhere it's currently 13-14.

As an aside, I'm sure I read somewhere that tracert can be used to identify congestion. I could well have dreamt that so apologies if I'm talking cobblers. Anyhoo, here is my tracert for the beeb, maybe it could shed some light?

tracert bbc.co.uk

Tracing route to bbc.co.uk [212.58.241.131]
over a maximum of 30 hops:

1 1 ms 1 ms 1 ms 192.168.1.1
2 5 ms 6 ms 5 ms 213.120.155.227
3 6 ms 6 ms 6 ms 213.120.155.158
4 6 ms 6 ms 6 ms 213.120.161.18
5 6 ms 7 ms 6 ms 217.32.26.62
6 7 ms 6 ms 6 ms 217.32.26.182
7 6 ms 6 ms 6 ms acc2-10GigE-0-0-0-6.bm.21cn-ipp.bt.net [109.159.
248.210]
8 16 ms 14 ms 14 ms core1-te-0-2-5-0.ilford.ukcore.bt.net [109.159.2
48.128]
9 11 ms 11 ms 11 ms peer2-xe10-0-0.telehouse.ukcore.bt.net [109.159.
254.128]
10 25 ms 11 ms 11 ms 194.74.65.42
11 * * * Request timed out.
12 13 ms 12 ms 11 ms ae1.er01.rbsov.bbc.co.uk [132.185.254.46]
13 11 ms 12 ms 12 ms 132.185.255.134
14 12 ms 11 ms 11 ms 212.58.241.131

Trace complete.

Maybe my best option is to just hold tight for a few months and see if the situation improves.

The minimum is over the BT that Openreach run, once its left the exchange it is BT wholesale and BT retail who are the two main components if on Infinity

Openreach guarantee a minimum throughput to the exchange. But if from there your ISP has opted to only make available a lower speed (through throttling, congestion, whatever).then... Well, it's a matter between you and your isp.

Openreach guarantee 15mbps but BT's speedtester thinks 12mbps is the minimum acceptable, many ISPs also guarantee 12 on consumer and 16 on business services so I'd assume it's the norm.

In any case I saw similar behaviour on my Infinity line about a month ago, where throughput dropped from 38mbps at peak times one day down to 4-6mbps the next. It was down to congestion, not throttling - note that throttling would *not* cause an increase in ping but congestion normally does.

For me it occurred several weeks before the 80mbps became available, and solved itself about five days later; speeds went straight back up from 4-6mbps to 38mbps again by itself, and since 80mbps came out I've been hitting a constant 77mbps at peak times.

In reply to a post by qasdfdsaq:

and solved itself about five days later; speeds went straight back up from 4-6mbps to 38mbps again by itself, and since 80mbps came out I've been hitting a constant 77mbps at peak times.

I'm hoping mine does exactly that.
I was switched to the 80/20 product earlier today and I now have an upload speed greater than my download speed.

Download speed achieved during the test was - 7 Mbps
For your connection, the acceptable range of speeds is 12 Mbps-77.43 Mbps .
Additional Information:
IP Profile for your line is - 77.43 Mbps

Upload speed achieved during the test was - 13.26Mbps
Additional Information:
Upstream Rate IP profile on your line is - 20 Mbps

So much for the assured rate over the 80Mbps product being 30Mbps (I read somewhere on here). Clearly that's an Openreach assured rate and nothing at all to do with BT retail (my ISP)

If only my line was short enough to give good speeds over 24Mbps ADSL2+ (although if it were, I wouldn't have switched to Infinity in the first place - I'd have stayed with BE).

Isn't the last stage of the BT speedtester (using a generic non-ISP related log-in) supposed to bypass the ISP and test the actual line capability (i.e. removing ISP throttling/congestion from the equation)?

Another person with congestion issues with the Shrewsbury exchange here. I am not on fibre as it got delayed on my cabinet until June but since switching to sky and their network I get much slower speeds in the evenings (I switched in mid march so it could be coincidence, although it never happened on talktalk).

May I ask what part of Shrewsbury you are from?

Edited by deleted (Mon 23-Apr-12 17:38:32)

Try a quick speedtest.net check but use the XILO server in Manchester.
So far it's the only speedtester and server combination from which I have been able to get a decent result.

Just got this from the Xilo Manchester server, this from their Maidenhead server, this on automatic (just click on 'Begin Test' and it selects the server with the lowest ping) and this from the ThinkBroadband tester.
Clearly we cannot rely on the TBB tester for accuracy as it seems to be out by a factor of 6 (or 7) on the download test and by a factor of three on the upload test.

Either way (and excluding the obviously flaky TBB tester) the problem here certainly seems to have improved for me (it's got better even over the last hour or so).

My actual download speed (using multi-thread or multi-split download applications, such as Usenet) is currently around 75Mbps.

It's almost looking like domestic broadband connections (or the number of people doing simultaneous speed tests) is getting too much for the test servers!

Edited by adebov (Mon 23-Apr-12 18:38:31)

12 Meg being lower than 15 makes total sense, but it is certainly not as firm a figure as the CBR.

The cost of keeping spare capacity so every FTTC customer can hit 12 Mbps at anytime is horrendous

Hi Ade,

if it makes you feel any better, the same is happening here, rock solid until my 80/20 service came on. At one point yesterday the BTw tester showed 3meg download, and the speedtest@speedtester_domain showed 5.

I decided I might as well raise my concerns, as the tester told me to. Three phone calls to Tech Mahindra (at least they are free). I politely informed the helpdesk guy that if they did try and book an engineer visit, it would most likely be me that came.... First blamed on a 'network issue'. The line is spot on.

Then suggested that an engineer visit would be required.......Perrrr-leease.

Then had me swapping round the ethernet ports, and on finding that there varying results on each test, stated the router must be faulty........
" I'll send you a replacement"
" But I have replaced it already ?"
" How?"
" I have a spare"
" but I'll send you a replacement,"
[sigh] ...... OK, go on then.


So, clearly no further forward, but I feel it's like voting, if you didn't then you shouldn't complain about the Government. *Maybe* if we all make enough noise ??

Oddly enough it's a little better today (80/20 was enabled in the early hours of this morning and, much to my surprise, I'm getting maximum sync in both directions - I was expecting around 60Mbps).

Still very flaky with certain speed testers (TBB is the worst) and switching between speedtest.net server locations gives wildly different results.

All I know is the same as you - begger all wrong with the line, modem, router, blah, blah (and certainly nothing to do with ethernet ports or Windows installations).
But you can't blame the guys in India. The blame for dodgy tech support must be placed firmly in Ipswich (or wherever they write the stupid scripts).

I'm hoping it's more to do with so many getting 80/20 upgrades and hitting the speedtesters, then hitting them repeatedly when getting rubbish results (which either Bob or Andrew suggested).

I can't think it's a widespread congestion issue (otherwise I wouldn't be getting full speed from Usenet and multi-thread downloads). Also pings seem largely unaffected (maybe a touch higher than normal, but only by around 10%) so that also points away from congestion.

It's either some weird routing issue, too many speedtests or throttling (which would affect single-thread downloads and speedtest results).
If I were a "glass-half-full" person I'd say it's the middle, but my "seen it all too many times before" experience says it's throttling.

My local cabinet is just by the Oxon pub

Just checked my speed tonight and it's the fastest it's been for about 2 weeks! I wonder if someone is monitoring these forums and has just turned a dial up to 11

Well it's back to being rubbish again.
Gone midnight and single thread downloads (and speedtesters) are back at around 5-10Mbps from an 80Mbps connection.
Multi-thread downloads (download managers and Usenet) are still able to go close to full speed.
Without a shadow of a doubt the BT network is being throttled (or there's something seriously wrong with their Home Hubs or the cheap Chinese modems they've given us).

I can't really think of many explanations (other than throttling or traffic shaping) which would cause single thread downloads to struggle to get faster than ADSL1 speed whilst multi-thread can go all the way up to full 80/20 line speed.

Fortunately you don't really need more than around 4Mbps for regular web surfing but that's not really the issue here.
I fail to see the point in BT bothering to spend millions (possibly billions) rolling out 40/20 and 80/20 FTTC across the country when the actual useable speeds for most customers are little higher than the ADSL2+ speeds which have been available from BE for years.

Are you testing with files other than TTB ones? Because they have never given me consistent speed. Try the files at leaseweb. Single threaded downloads give me a nice flat line in task manager at 73.7Mb/s.

In reply to a post by Croftie:

Try the files at leaseweb. Single threaded downloads give me a nice flat line in task manager at 73.7Mb/s.

Even worse - single thread download of an Ubunto ISO is going at 2-4Mbps.
Multi (ten) thread is going at 28Mbps (on an 80Mbps connection with a full speed sync).

The test files at TBB are doing around 3Mbps per thread (so 3Mbps for a single thread and around 36Mbps when all twelve threads kick in).
Speed is very bouncy (can peak at up to 4Mbps per thread).

Basically BT seem to have real issues (although it's not affecting everyone), but you kind of get the idea these speed issues are real when Openreach engineers (who install FTTC connections for a living) are ringing up BT "support" and complaining of poor speeds!

As usual Usenet is going at full line speed (using Newsbin, which is reporting between 70-78Mbps).
So this proves there's nothing wrong with my line.
If I had line issues Usenet wouldn't be able to go at full speed and the problem is most apparent during the day (weekdays and weekends for me - basically as soon as we hit 7-8am, right through until around midnight, single thread speed falls by around 95%).

So, put simply, BT are throttling (or traffic shaping) there's no other reasonable explanation.
It may be on a local level, or maybe in the South/Midlands (me in Oxfordshire, another near Reading somewhere and one in Shropshire, plus many others I'd expect) but BT are throttling.

Edited by adebov (Thu 26-Apr-12 18:51:32)

History has lots of evidence showing this is not uncommon after a major speed upgrade.

0.5 to 1Meg
1Meg to 2Meg
2Meg to Max

It was not uncommon to have a few weeks of congestion, then VP's got resized and all was well. Perhaps BT Wholesale never gets the VP sizing correct, and underestimates the sharp rise in demand from consumers.

Believe I've seen this TCP single thread throttle before affecting BT Wholesale traffic

In reply to a post by MrSaffron:

History has lots of evidence showing this is not uncommon after a major speed upgrade. Perhaps BT Wholesale never gets the VP sizing correct, and underestimates the sharp rise in demand from consumers.

Believe I've seen this TCP single thread throttle before affecting BT Wholesale traffic

I wonder if allowing existing users to upgrade at the same time as all new customers are automatically given 80/20 lines is a major cause of the problem.
Let's face it; most people [when getting FTTC for the first time] will tend to hammer away at it and existing users are even more likely to do the same when doubling their connection speed.

Hopefully BT will resolve this issue (they must be aware of it simply because it looks like "real" intentional throttling, rather than congestion) as their networks can't be too overloaded because many people seem to be unaffected by the throttling (evident by posts on here) or are blissfully unaware the throttling is even taking place!

Just tried a ubuntu download and single thread was 2-3Mbps, it would only allow 5 threads giving about 9Mbps. Other downloads are running full speed though.

I don't doubt your seeimg issues but for me at least TBB and ubuntu aren't a representative measure.

Here are some more for you to further prove your issues, for referance they all give full single threaded speed for me:-

http://speedtest.tweak.nl/100mb.bin
http://london1.linode.com/100MB-london.bin
http://cachefly.cachefly.net/100mb.test
http://www.pro-noc.nl/1000mb.bin

May or may not be relevant but my speed re-grade only kicked in this morning. I expected wildly fluxuating speeds initially based on what I'm seen from others, but so far it's been very consistent.

One dissapointment is the upload speed to rapidshare, before the regrade I got a single threaded speed of 600-850KBps out of 1130KBps, after getting 950-1050KBps out of 2200KBps. I've contacted both rapidshare and BT about it in the past but neither will confirm or deny a problem or throttleing.

It is suprising how quick the GB's pile up at these speeds isn't it, 22 so far today just testing the up/download. I wonder if lot of people are hammering it in your area ATM.

Edited by deleted (Thu 26-Apr-12 21:32:22)

The last one you listed (the 1000MB file from the Netherlands) is doing 6Mbps single thread and 68Mbps multi-thread.
I can't get any of the ones you listed to go faster than 16Mbps single thread.
It's not just TBB and an Ubuntu download which are slow for me (in single thread mode), it's everything (other than the BT beta speedtester, which curiously gives a 74Mbps result when all the others are below 15Mbps this evening).
All single thread downloads I try (what ever and from where ever) are slow.
All multi-thread (again; what ever and from where ever) are at full speed - provided there are enough threads going (needs maybe 15-20 to push to full speed).

This connection, here in Oxfordshire (and via whatever routing path BT are using) is being throttled, no doubt, no other reasonable explanation from what I'm seeing (and I'm not the only one to report it).

Edited by adebov (Thu 26-Apr-12 21:42:15)

Yep no getting around you have a problem, those extra links prove it beyond doubt.

a not high enough tcp buffer will cause slow per threaded speeds however if this is something that wasnt happening to you before then it would seem thats not the case.

In reply to a post by Chrysalis:

a not high enough tcp buffer will cause slow per threaded speeds however if this is something that wasnt happening to you before then it would seem thats not the case.

Well it's not that (I can't think how the TCP buffer size would automatically change itself, getting smaller at 7am and correcting itself around midnight).
It's throttling, pure and simple.

I have now got fibre and am experiencing the problems you are experiencing too. It was actually all fine for the first week but since this sunday I have been getting inconsistent slow throughput in the evenings.

Maybe there is a problem at the Shrewsbury exchange?