Any ideas what's going on with these graphs?

My broadband woes continue. As winter approaches my broadband suffers, normally I'd start to have problems from around November onwards but this time I've started to get problems from around July time.

I've always had a lot of background noise on the telephone line, so much so that the handset has been disconnected for well over the last year as you just couldn't hear anybody plus using the handset would cause the connection to drop. It's taken me from July to Wednesday just gone to get a BT engineer in to have a look, his quiet line test failed and he found a line fault from the green box back to the exchange and swapped over the conductors I use. The noise on the line has now gone, whilst the engineer was there the broadband looked fine so he left but later in the day I started to get problems.

Talktalks answer is just keep on raising the SNR margin which does nothing, I'm currently on a 15db profile but I still get graphs like the ones attached.

Talktalk don't seem to be interested in anything except increasing the noise margins but the real problem with the line is still there. One thing I have noticed is that it is definitely the upstream connection that's dropping first, this in turn seems to pull the entire connection down.

To date I've replaced the router, have had the faceplate replaced, replaced the telephone handset, I only have the single socket with just the router and handset connected. If anybody can offer any advice I'd really appreciate it.

http://img.photobucket.com/albums/v280/IAmATeaf/sync...
http://img.photobucket.com/albums/v280/IAmATeaf/sync...
http://img.photobucket.com/albums/v280/IAmATeaf/snr-...
http://img.photobucket.com/albums/v280/IAmATeaf/snr-...

The graphs

How is the quiet line test now, (17070 option 2), using a corded phone into the test socket, (not the external socket on the master)?

If that is clear, what is it like with everything connected normally?

Is your central heating running earlier this year, with the weather we have been having?

(Edit - and you are on a 6dB downstream noise margin and seemingly 8dB upstream)

Edited by RobertoS (Fri 09-Sep-11 09:25:32)

Apart from a very low constant background hum there is none of the crackling and popping that used to be there, I've tried this from the main master socket and via the faceplate.

No, I've not been using the CH, haven't turned it on yet.

My snr margin or profile was changed to 15db last night and according to TT the line is now stable but when using the internet I get pauses which coincide with the most recent graph traces I've just done.

Surely the snr jumping around that much can't be normal can it? Also on the snr graphs the lines are black and red, whenever the line goes red I have no interent till the line goes back to black but TT say there are now no disconnects. Very frustrating.

http://img.photobucket.com/albums/v280/IAmATeaf/sync...
http://img.photobucket.com/albums/v280/IAmATeaf/sync...
http://img.photobucket.com/albums/v280/IAmATeaf/snr-...
http://img.photobucket.com/albums/v280/IAmATeaf/snr-...

In reply to a post by IAmATeaf:

Apart from a very low constant background hum there is none of the crackling and popping that used to be there, I've tried this from the main master socket and via the faceplate.

No, I've not been using the CH, haven't turned it on yet.

My snr margin or profile was changed to 15db last night and according to TT the line is now stable but when using the internet I get pauses which coincide with the most recent graph traces I've just done.

Surely the snr jumping around that much can't be normal can it? Also on the snr graphs the lines are black and red, whenever the line goes red I have no interent till the line goes back to black but TT say there are now no disconnects. Very frustrating.

http://img.photobucket.com/albums/v280/IAmATeaf/sync...
http://img.photobucket.com/albums/v280/IAmATeaf/sync...
http://img.photobucket.com/albums/v280/IAmATeaf/snr-...
http://img.photobucket.com/albums/v280/IAmATeaf/snr-...

No it should be more or less a straight line on SNR but some degree of fluctuation is normal , sync should be a continuous straight line

Evidence it's self of a possible fault as they have raised the target SNRM to 15db in a bid to hide the fault,

I get the impression that as they now class the line as stable they won't be willing to listen or do anything.

I have given them copies of the graphs.

I've told them that their solution is is bit like me taking my car to the garage and reporting that it cuts out at 50mph, the garages responds with the proposed fix that I should only drive at 30mph.

Ummm.

Comparing your first set of graphs with your second, note that in the first set the up and down sync's change with several of the disconnects. In the second the sync's are rock solid. That would tie in with them saying you are not getting disconnects on the higher margin.

I've no idea what I'm looking for here, but it seems to be something stopping the traffic but maintaining sync.

I'm a bit confused by the graph colours, I think it is full RouterStats, not Lite, which I know more about. However, on Lite the graph stays the normal colour, (black), through a disconnect, and when the down-spike is red it means the router was too busy doing its real job of transmission and error-correction to bother responding. Those red spikes rarely if ever had a flat bottom.

I think some full RS graphs are red to start with, and the uploads you've given us aren't easy to analyse for colour changes.There are obviously a lot though, which is suspicious unless that is the norm on your version. Are there any that don't change colour?

Other than that, I'm a bit stuck for now, but gut feel says it could be something at your end that we haven't thought of.

The router is a brand new Netgear DGN1000 which looking on the internet has it's fair share of users with problems, but then again that's the internet for you, I don't post when things are fine only when things go wrong so it's not surprising that I get loads of hits back about people with problems.

Is there any way that TT can tell why the line lost sync and which end let go? I have asked them but they say that all they can see is that it lost sync and not much else.

Edited by deleted (Fri 09-Sep-11 14:32:27)

I tried a different power supply for the router and tried a different modem to master socket cable but I still get the fluctuations.

Stupid question time, but is there any way I can confirm that the new modem may be faulty? I don't have a spare either to test with

Take it to a friend's and see if it plays up there as well, or works fine. Preferably someone on LLU so you don't completely screw their line if it is the router.

Edited by RobertoS (Fri 09-Sep-11 21:37:06)

To date I've replaced the router

?

(Edit - did you also replace the power supply to it with the new one, as it could be that failing).

Edited by RobertoS (Fri 09-Sep-11 21:39:12)

I replaced the PSU with the one that came with the router. When I mentioned in my post above that I replaced the PSU I used the older one, which to my eyes looks like a much better PSU and much heavier but got the same results.

Various facilities were designed into the DSL spec for diagnostics and are implemented in kit at both ends (exchange end and customer end) but most service providers ignore most of them.

A decent router will not only allow you to monitor upstream and downstream sync speed and noise margin, it will also allow you to check line level error counts. If you're really lucky it'll keep separate counts of the various different kinds of error. Really any modem/router without this facility shouldn't be on anybody's shopping list, especially on any ISP's "standard router" list, but I guess Netgear have had some sweeteners on the table.

My favourite for this a while back was the BT (yes really) Voyager 2110 (it's actually a 3Com of some kind), currently on eBay for under a tenner 2nd hand, though 2nd hand kit and an existing problem may not be a bright idea. No idea what the modern equivalent would be.

I don't know routerstats or your router well enough to know if the combination offers the capability to monitor those line level numbers but that's where I'd want to look next. Perhaps someone else could comment?

This Netgear box gets some of the worst Amazon reviews I've seen for a while. In your circumstances in the first instance, I'd be tempted to acquire another modem/router, preferably one with decent line diagnostics.

Good luck.

TBH, I half tempted to junk the DGN1000 and get another router, anybody got any recs on something decent that will offer good wireless coverage?

TT, are arranging for another BB guy/gal to come out and take another look, so here's hoping that he/she finds and fixes the problem.

Edited by deleted (Mon 12-Sep-11 10:48:17)

I nearly suggested that the other day...
I can recommend something with a Broadcom chipset - it transformed my line!
See link in sig...

EDIT: And when you're having ADSL issues I wouldn't worry about the wifi coverage - getting a stable ADSL line is more important! You can always add wireless access ports or repeaters etc. to overcome poor wireless

Edited by b4dger (Mon 12-Sep-11 11:05:26)

Quick update, TT have confirmed that they don't suspect the router as there are downstream errors being reported, they've said that if they suspected the router than they'd have thought that there would be upstream errors?

That doesn't make sense to me!

Means nothing to me either

I've just had a look at your blog and that is some impressive connection speed if you line att is 50/51db. My line att is 39db and I only just about manage to connect at around 5100kb/s.

It took me a while to find the right router - and also make sure my internal wiring etc. was as clean as I could get it

I'll try to put a new RouterStats graph up soon showing things with my 6db TSNRM.

Is the newer variant of your router still a good router to go for?

Am going to wait till the engineers been, hopefully he'll find a fault and fix it but if not then I'll look at replacing the router.

I'm not 100% sure on that! Quite often corners are cut to make things cheaper!

I've bought a couple of ST585v6 from eBay - both new and boxed ex-AOL ones.
At £30 it's worth having a backup

The Netgear DG834GT or DG834v4 (must be version 4) also use Broadcom chipsets.
Or the Billion 7800n - also Broadcom is getting good reviews - see the TBB DSL Hardware forum where there are a number of Billion threads

EDIT: Just looked on eBay and there are a number of cheap 585's - might be worth a try...

Edited by b4dger (Tue 13-Sep-11 11:36:03)

Well the BT Engineers been and gone. From my master socket he could see the drops when he had his test equipment plugged in, said he would test from the cabinet. He also said that he could see the drops from the cabinet but the answer to the problem is to increase the SNR margin yet again. So TT have now increased the margins which does seem to have stabilised the line from what I can see but the net result is that where I used to have down speeds of around 7100k I now have 4700k and where my up speeds were 700k it's now 491k.

The Engineer watched routerstat for some 10 minutes and it was flat, 10 minutes after he left it started pulsing to 0 but luckily he was still in his van, went to see him and he said that he was told that it take a good hour before the changes would take effect so there was nothing else for him to do.

Hmm, I'm not too convinced but the Engineer is convinced that there is nothing he can do and that he really shouldn't have been called out.

Well some success to report.

I've had my profile changed to interleaved 12db 8M and the spiking on the upstream stopped, so they changed it to interleaved 9db 8M and the spiking started so I then checked the router settings and changed the router from Auto to ASDL (G.DMT) and the upstream SNR margin is now completely flat. I'm currently on a 6db profile with flat snr margins. The line did re-sync some 4 hours ago but I'm wondering if that's when the line went from 9db to 6db.

Going to monitor it today, here's hoping that the line is back to normal and I hate to say this but the Engineer from yesterday and what he said could have been right

Sounds good. But also sounds like you could get a hefty BT bill

I hope not, TT were seeing CRC errors, the engineer also confirmed that he could see CRC errors on the line, although there weren't as many as TT had reported, his words not mine, whatever that means.

CRC errors are a normal part of ADSL though...

Hmm, will have to wait and see if they do try and bill me but the line is still stable, hope I'm not tempting fate by boasting

Remember to let us know how your get on!


NB. I updated my low snr page today with an up to date RouterStats graph...

The line is still stable, have got my speed back too, back on a 6db profile and syncing at around 6848kb/s down and 832kb/s up

That good to hear! It feels great when a broadband problem is sorted


You probably won't know for many weeks whether BT will bill you or not.
When your ISP arranged the engineer did they go through all the warnings about possible charges?

Nope, I was getting peeved off at the time and I think I'm right in saying that it was them who suggested that an engineers visit is needed.