Speed drop all of a sudden?

[andrue]

I wish I'd not said anything.

Puts me in mind of some of the bug defects I've raised internally at work.



But I apologise if I annoyed anyone.

[mervl]

"So as before - it's just getting throttled somewhere in their system again."

If that's true won't others on the exchange be having the same problem, so would it help to check with a few neighbours? Unless the exchange is reported as congested, perhaps. And if there's a PoP problem wouldn't others be shouting about it? Router? - mine (IDNet's supplied model actually) was a limiting factor until I changed it.

[andrue]

"So as before - it's just getting throttled somewhere in their system again."

If that's true won't others on the exchange be having the same problem, so would it help to check with a few neighbours? Unless the exchange is reported as congested, perhaps. And if there's a PoP problem wouldn't others be shouting about it? Router? - mine (IDNet's supplied model actually) was a limiting factor until I changed it.

I might check with one of my neighbours - didn't get around to it last time. I don't think it's the router though - speed to my server is still fine and in any case it seems to be a temporary thing. It's only done this for about two weeks out of the four months I've had the service. In both cases it seems to be preceded by speedtest.net showing variable throughput which does make sense. Also the speed seems to max out at 30Mb/s which if I remember correctly someone found a BTor link saying that was the speed used when congestion was a problem.

Edit: Here we go - http://www.openreach.co.uk/orpg/home/updates/briefings/super-fastfibreaccessbriefings/super-fastfibreaccessbriefingsarticles/nga00612.do

"What speed will lines with the 80/20 product variant receive when the network is congested?
Openreach has implemented a downstream Prioritisation Rate (PR) for each of our downstream product bandwidth variants.  In the event of network congestion, we will decrease line speeds momentarily to reduce the congestion as follows:

Product bandwidth variant purchased Prioritisation rate
Up to 40Mbit/s                               15Mbit/s
Up to 80Mbit/s                               30Mbit/s"

Although quite how that ties in with 24/7 throttling I don't know. Doesn't sound like 'momentarily' to me and I struggle to see how there can be congestion at half past six in the morning.

[andrue]

Hmmm. Powercycled my router (not the modem) this morning and it came back at full speed. I didn't have time to wait though so I don't know if it's a permanent fix. Last time this happened a router reboot appeared to fix it but half an hour later it was back to slow mode.

[Steve]

Remind me which router are you using?

[andrue]

Remind me which router are you using?

WNR1000v3. I think it's the same one IDNet sell but I bought mine myself.

One thing I have noticed (which probably means nothing) is that speedtest.net thinks I'm in Macclesfield and thinks my preferred server should be Preston. I've just assumed their Geolocation DB is wrong - Google and others know where I am. I did find a few references last night to issues with FTTC and mis-identified location though. Something called 'The Dominoes Pizza Test', lol.

http://helpforum.sky.com/t5/Sky-Fibre-Unlimited/Can-someone-elaborate-on-the-Dominoes-Pizza-search/td-p/460558

[pctech]

Webkit (rendering engine for both Chrome and Safari) is cr*p so why would they support it?

[Steve]

Re the WNR1000v3 I believe that's 10/100 ethernet and on that assumption I wonder if the wan to lan transfer speed maybe a bit borderline for FTTC. I don't know for sure though.

[andrue]

Re the WNR1000v3 I believe that's 10/100 ethernet and on that assumption I wonder if the wan to lan transfer speed maybe a bit borderline for FTTC. I don't know for sure though.

Doesn't really explain why it cuts me down to 30Mb/s for three or four weeks out of 4 months though. For example it seems to have been fine since the end of June. So that's nearly two months of full speed (the mchs test and TBB showed >78Mb/s) then suddenly the brakes come on. FWIW that mchs test when it's working tends to show at least 90% consistency. Quite often it shows 99%.

[andrue]

The plot thickens. Looking at TBBQM graphs:

Yesterday:

Today


Things to note:
You can see where I rebooted the router this morning just before 7am. But notice the overall activty. Prior to this morning there was constant albeit low grade activity after 7am (which is when the house becomes empty) on the top graph. Since rebooting the router it's been very quiet. I haven't been home so don't know if the speed is still 'good'.

And here's the graph from last Friday - the last weekday when speed was good:



Another quiet graph. The peaks would be me doing a speedtest. I'm beginning to think it's a routing issue. Something happened Sunday night that put me on a cr*ppy route.

[andrue]

Still seems fine this evening:

Download speed    72190 Kbps
Upload speed    16963 Kbps
D/load COS    95 %
U/load COS    96 %
Min RTT    2 ms
Max RTT    16 ms
Avg RTT    10 ms
RTT Consistency    12 %
Max Delay    8 ms
Avg Delay    1 ms
Effective Speed    73285 Kbps
Route Speed    262140 Kbps
Forced Idle    30 %

So either my router or BT's network got its knickers in a twist   

[andrue]

Now there's a thing. My connection has gone slow and jittery again. I was away at a wedding but on Saturday it went wobbly.

You can see the jitter start.
Before:


Change over.


Today:


And just for reference during the week there is rarely anyone home to use the connection so it's 'idle' between 11pm and 4pm give or take occasional incoming spam mails.

What's rather curious is the pattern of dates I'm seeing:

* First occurrence - June 19th.
* Second occurrence - August 19th.
* Third occurrence - October 19th.

When did my connection go live - April 16th. Now I've been in this game long enough to know that coincidences happen but the above pattern seems very suspicious to me. Basically every two months my connection develops a bad case of the jitters and speeds struggle to get above 30Mb/s (instead of being a steady 76Mb/s). You'd think someone at IDNet or BT would think that interesting enough to do an investigation. I'm a software developer and if someone reported something like that to me I'd be on the case.

[Technical Ben]

Are they trialling updates during that day?

[andrue]

Are they trialling updates during that day?

I suppose they might be. It'll be interesting to see what happens in December. I power-cycled my router because of the congestion thread so if it goes wobbly again on the 19th it'll suggest that it's not my router causing it.

[andrue]

I thought it wasn't going to happen this time but lo and behold here comes the jitter:



And speedtest.net is hovering around 30Mb/s again. I'll reboot my router and then look forward to the 19th of February. Maybe I can persuade Support to take it seriously between now and then 

[mervl]

I've never had anything on a regular cycle like that on VDSL2 (FTTC). The only thing I will say with the Fritz! modem's ability to monitor my connection is that sort of disturbance when it occurs (infrequently - approx once or twice a month, though on the occasional month I get none) on my line is symptomatic of a problem at the BT interconnect (PoP) reported by my modem. But as with this morning's incident I reported on another thread, invariably overnight; and usually correlated with something on AAISP's or Zen's checkers. The usual law will say your issue is completely different, but is there any other evidence of a local loop fault or recent work on local lines where there may be a dodgy joint intermittently affected by damp?

In fairness to ISPs I think when it comes to the BT residential network customers can get better info from their modem's reporting than the ISP has access to via BT! It's bad luck that OR disable this facility (but most people don't want it and that's what you get in a democracy!). The key factor with my non-"issues" is that while actual uploads swing about (which I conclude is due to my poor quality local loop which suffers an attenuation of 20db from the Cab), the reported attainable upload and download is consistent at +/- 5% as is the SNR margin within a 1db range; and reported DSLAM disconnects are consequently at 1 or 2 a year which I think has to be expected with the work of a well-performing modem, as it needs to recover (from my meddling, apart from anything else) occasionally. Speed checker reporting (apart from the BTw one) do vary though (with seemingly "roguish" readings), but not  actual throughputs very often as far as I can tell.

[andrue]

is there any other evidence of a local loop fault or recent work on local lines where there may be a dodgy joint intermittently affected by damp?

Nothing I'm aware of. It rained a fair bit yesterday but we've had worse. Brackley is subject to real monsoon like downpours at any time. I checked the modem and it claims to have been connected at over 74Mb/s for over a month so I left it alone. BT Speed tester said 29MB/s on a 72Mb/s profile. Apparently my acceptable range is 0-12Mb/s whatever that's suppose to mean 

I couldn't get the speed to recover last night despite leaving the router powered off for half an hour. I did a disconnect reconnect this morning though and it seemed better (though still pretty cr*p). Unfortunately at this time of year there's no point pestering Support. I'll just have to hope it recovers eventually - it always has in the past.

But I've marked February the 19th in my diary - that's when it's next due 

[andrue]

I'm thinking this morning's reconnect didn't help. I can't test from work but judging from the latency spikes it still isn't back to normal:



Looks pretty active for an empty house. I don't even have a budgie to blame now 

[andrue]

Well whatever the problem is - it certainly isn't 'interference' like Tech Support's 'Nick' kept suggesting:



Not unless the 'interference' is a special kind that only affects internal Cat6e cabling without bothering the modem/DSLAM 

Whether or not I'll ever get them to take it seriously and investigate it remains to be seen. So far my attempts to resolve it by rebooting my router have failed but looking back it seems they only ever worked a few days after it started. That may be another 'feature' to add to it so far I have:

• It starts on the bi-monthly anniversary of my connection going live.
• It starts three days after the activation date.
• Rebooting the router three(?) days after it starts fixes it.

My current theory is that my old 40/10 profile is somehow still active and every two months BT's systems try to retrain it and spend three days fighting the 80/20 profile before giving up.

[mervl]

Doesn't it look like a router issue then . . . if the OR modem (which negotiates the line speed with the DSLAM, I thought) remains connected and the IP profile doesn't change? (The 12-0 minimum reported by the BTw tester is, I gather, a known error for all of us).

[andrue]

Doesn't it look like a router issue then . . . if the OR modem (which negotiates the line speed with the DSLAM, I thought) remains connected and the IP profile doesn't change? (The 12-0 minimum reported by the BTw tester is, I gather, a known error for all of us).

It's hard to see it being the router though. It's been power cycled several times over the last eight months. It would have to be a firmware bug that hobbles the router for three or four days on the 19th of every even numbered month.

Hmm.. Actually, no, of course it can't be the router. I logged in directly using my laptop on Thursday and it showed the same problems. That means it has to be the OR modem or some other part of BT/IDNet's network.

[mervl]

Do the neighbours get a similar effect on their connection? I've some sympathy with IDNet if you've eliminated anything in your premises or on your local network being responsible: if it's on a regular cycle some interfering equipment in the locality that's operated regularly on a cycle but infrequently seems a plausible possibility. What's the modem showing for CRC errors/error seconds at the time compared to normal? If desperate, you'd have to try walking back to the cab whilst it's occurring with an appropriately tuned AM radio I suppose, and listening (and hoping) for some serious interference. Any possible culprit from a visual inspection? Radio hams, or the obvious industrial/commercial activities but the infrequency perhaps makes that less likely?  At least you can plan ahead! If so, what next is the problem . . . though I think Ofcom have powers to deal with radio equipment interference.

[andrue]

I'll try and check with a neighbour when I get back home the other side of Christmas but all that will prove - if they use another ISP - is whether or not it's a cabinet or exchange issue.

Interference just doesn't make sense. The tool that produces that graph has a continuous mode and I ran it for half an hour today. The bits per tone and SNR graphs barely wavered. If there is interference all it's done is dropped my speed a maximum of 9Mb/s from 80 down to 71.

You can't be connected at a steady 71Mb/s and claim that interference is capping throughput at 30Mb/s. It's nonsensical. If I'm averaging a 71Mb/s connection then that's what my modem is capable of pulling from the cabinet.

[Simon]

This is a total shot in the dark, but it couldn't be something like a Sky box updating bi-monthly, could it?  I don't have Sky, so have no idea how often they update.

[Gary]

This is a total shot in the dark, but it couldn't be something like a Sky box updating bi-monthly, could it?  I don't have Sky, so have no idea how often they update.

Sky boxes may update a handful of times a year Simon, and that's via satellite, also the newer sky boxes have pretty much zero effect on phone lines.