Sync speed and IP Profile getting lower and lower

This all started around Sept/Oct last year (2012). After being on a rock solid connection for about 4 years, sync'ing anywhere between 5000/6500, my connection sometimes stopped working (but modem was still in sync - sort of like making a phone call where nobody speaks) - so I had no data through-put. The only solution was a reboot/reload.

All the above was with a Cisco 857 dsl/modem. So over Xmas holidays, I found latest firmware for the problem above and also a crafted firmware for special use with BT's kit at the exchange. All worked great for a day or so, but then I started to get disconnects in the evening and early morning - and every time that happened, modem would resync about 2000 LOWER, and IP Profile dropped accordingly (until I ended up sync'ing around 1500). But no matter what I done, I could never get a decent sync back. Checking with the BT speed test, it turned out that after every disconnect my sync rate got 'capped', so no matter what I done, I was stuck on a low connection speed.

My ISP, Enta have been very good, and we tried everything (reset this, reset that etc.). Same problem.

So clutching at straws I bought a TP-Link adsl modem/router, got eveything reset and off we go.

Yesterday, I was connected at 5420, with decent noise margins, IP Profile of 4500. Hunky Dory!

Then last night, I got a disconnect, now can only resync at 3000. BT speedtest thing reports my line is now only capable of 4Mb, and my profile is now 2500.

I can be sure that it will disconnect again tonight some time, and my sync will drop to around 2000, profile will drop to 1500, and max line speed will drop too.

So, why do BT cap the sync speed? How can the 10 day training period work it they cap what my line can do?

Here are my latest stats:

Line Status:Connected
DSL Modulation Type:ADSL_G.dmt.bis
Annex Type:Annex A/I/J/L/M
 	              UpstreamDownstream
Current Rate (Kbps)	1128 	3070
Max Rate (Kbps)      	1128	 9424
SNR Margin (dB)	         5.9	17.4
Line Attenuation (dB)	22.4 	39
Errors (Pkts)	           0	  0

Two things to note: I connect using ADSL2, as 2+ is not worth it on my line length (about 3km). I have checked all wiring, filters etc.

Any help appreciated why this all started happening, and why now BT seem to 'cap' connection speeds which to me seems to do away with the way the profile thing works.

Nick

Edited by deleted (Tue 19-Feb-13 10:57:36)

The dlm systems react to drops in line. Fix those and things will improve time.

39 db should benefit a bit from adsl2+ suggesting dlm is reacting to a noise issue.

It may be upstream causing the line drops.

It is holding your Down NM too high.

SNR Margin (dB) 5.9 17.4

Edited by XRaySpeX (Tue 19-Feb-13 12:24:35)

In reply to a post by XRaySpeX:

In reply to a post by Lethe:

I connect using ADSL2, as 2+ is not worth it on my line length (about 3km).

You might have chosen ADSL2 but it has degraded you to ADSL(1):

DSL Modulation Type:ADSL_G.dmt.bis

It is holding your Down NM too high.

SNR Margin (dB) 5.9 17.4

I thought that, but my upstream speed is consistant with ADSL2 (ADSL is around 890?).

I will switch back to ADSL2+ as MrSaffon suggests and post stats bacxk here.

Thanks for your help.

Nick

Thanks for you help! I have switched back to ADSL2+, here are new stats (also note no increase in sync!):

Line Status:Connected
DSL Modulation Type:ADSL_2plus
Annex Type:Annex A/I/J/L/M
 	             Upstream	Downstream
Current Rate (Kbps)	1117	3071
Max Rate (Kbps)     	1116	10968
SNR Margin (dB)    	5.9	6.1
Line Attenuation (dB)	22.3	42
Errors (Pkts)    	0	0

So, do you think it could be a line fault? Something that happened around last Sept/Oct?

Nick

In reply to a post by Lethe:

I thought that, but my upstream speed is consistent with ADSL2 (ADSL is around 890?).

I understand that G.DMT has the same maxima as ADSL2.

You got me intrigued, as when I do connect with ADSL, I only get about 890 upstream (done all this whilst working with ISP to find out what is going on).

According to here:

http://en.wikipedia.org/wiki/G.992.3

ADSL.G.DMT.bis is ADSL2

Nick

You're right! I overlooked the 'bis'.

Different devices can have very different performance in different modes.

Dropped and reconnected at 06:35 this morning - now:

Download speedachieved during the test was - 2.6 Mbps
For your connection, the acceptable range of speeds is 1.2 Mbps-4 Mbps.
IP Profile for your line is - 2.71 Mbps

And this will happen again early tomorrow sometime (between 03:00 and 07:00ish), and my profile will go down again... and as I said to the tech guy over the phone, at this rate I will have to dig out my 33.6kB modem next week.

Is this indicative of a bad line? I just do not know what to try any more.

Nick

Telephone lines generally dont have faults that happen around the same time each day.

What may be happening is some radio frequency noise is being generated at this time of day causing a problem. If you know the IP Profile is following the speeds which it will, no need to run the BT test to find it out, the router statistics are much more informative in terms of line performance

Have you had any work done on, or changes to, your central heating in the last 12 months? Or has a next-door neighbour?

No fitness fanatic in the area bought an indoor running or cycling machine?

Yes, I been all through all this since November - there has been no change in my immediate environment. I ruled out central heating (I do not have CH, but neighbours do) as you could expect it to kick-in the same time every morning (i.e. like 04:00) - but my disconnects happen any time between say 03:00 and 07:00 - and only ONCE a day.

Nick

Well, could/would BT turn OFF this profile thing? I mean, I can connect at say between 5200/6700 and hold a perfect connection for 23h:59m:30s a day - then something happens, and I reconnect. Why can't I reconnect at the same speed? Why drop 50% off the line speed for 1 disconnect? It's almost like BT want me to change to their fibre network.

BTW, here is todays stats:

Line Status:Connected
DSL Modulation Type:ADSL_2plus
Annex Type:Annex A/I/J/L/M
 	             Upstream	Downstream
Current Rate (Kbps)	1033	3071
Max Rate (Kbps)	        1036	10996
SNR Margin (dB)	        9.1	6
Line Attenuation (dB)	22.4	42
Errors (Pkts)	         0	0

Nick

Edited by deleted (Wed 20-Feb-13 10:24:47)

Why can't I reconnect at the same speed?

Because the noise that made it drop the first time is still present and inhibits the speed it can reconnect at.

If you have 3071k downstream sync with a 6 dB SNR margin and a 42 dB attenuation then there's a fair amount of noise present when those stats were taken. If the noise had gone away the SNR margin would be up.

ETA - Could you leave it off overnight ?

Edited by yarwell (Wed 20-Feb-13 11:07:52)

In reply to a post by yarwell:

ETA - Could you leave it off overnight ?

Well, that is no advantage as when I reconnect my profile gets lowered each time (plus I run a few services).

So this is what I do not understand. How can I get any improvement if the BT equipment reduces my sync rate/profile on every disconnect? It never ever used to do this until Sep/Oct last year.

Nick

you haven't shown us any evidence that it is lowered each time you connect unless I missed it.

You've shown that something happens that makes it reconnect and it connects at a lower speed because of the something.

My idea was to avoid the something by not being online at the time - however if the SNR margin doesn't come up the problem is still present - unlike your OP where the SNRM was high so it had gone away.

I'm focussing on the sync rate here, the IP Profile is just a derivative / consequence.

Extracted the posted stats thus far :-

Current Rate (Kbps) 1128 3070
SNR Margin (dB) 5.9 17.4 ADSL_G.dmt.bis

Current Rate (Kbps) 1117 3071
SNR Margin (dB) 5.9 6.1 ADSL_2plus

Current Rate (Kbps) 1033 3071
SNR Margin (dB) 9.1 6 ADSL_2plus

Current Rate (Kbps) 928 3072
SNR Margin (dB) 10 24.5 ADSL_G.dmt

Current Rate (Kbps) 1131 8771
SNR Margin (dB) 6.6 3.8 ADSL_2plus
after line reset by ISP

Edited by yarwell (Wed 20-Feb-13 13:47:47)

OK, so here at stats at the mo:

Line Status:Connected
DSL Modulation Type:ADSL_2plus
Annex Type:Annex A/I/J/L/M
 	            Upstream	Downstream
Current Rate (Kbps)	1033	3071
Max Rate (Kbps)	        1028	11252
SNR Margin (dB)	        8.6	6
Line Attenuation (dB)	22.4	42
Errors (Pkts)	          0	0

Now, I should be able to sync a lot higher than that, agree? But doing the bt test diagnostics thing, it reports my line max speed is now 4mb. Well it isn't, as I said, I used to sync between 5000/6700. So I cannot sync any higher due to being capped. And that cap gets lower and lower on each disconnect. In a few days time it will report 2700 (or something) max speed.

I think Enta support got fed-up resetting the line, so I will not bother then again until next week.

Nick

This is after being connected at 5420 on Sunday/Monday - and remember I tried adsl/adsl2/adsl2+ a few times too.

Wait 'til Friday, I will see then.

Nick

Edited by deleted (Wed 20-Feb-13 11:47:36)

Now, I should be able to sync a lot higher than that, agree?

No, not if the SNRM is 6 dB. There's nowhere to go. You can't trade excess SNRM for more speed if there's no excess.

The SNRM shouldn't be that low at that speed with that attenuation, but if you reboot that it'll come back the same. This points to noise.

The only other possible explanation I can think of is that there's a rate cap set on it at 3070 and it's being power limited, but I don't think power limiting is used like that. community.plus.net/library/broadband/dynamic-line-management-dlm-on-adsl2/ shows that 3072 is indeed the top of a band but if you look at the comments below you'll see someone who is banded at this speed but gets a high SNRM that varies.

This is after being connected at 5420 on Sunday/Monday

Did you capture any stats for that ?

What happens Friday ?

I see... but I have just changed to ADSL:

Line Status:Connected
DSL Modulation Type:ADSL_G.dmt
Annex Type:Annex A
 	               Upstream	Downstream
Current Rate (Kbps)	928	3072
Max Rate (Kbps)	       1068	8576
SNR Margin (dB)	       10	24.5
Line Attenuation (dB)	22.5	41.5
Errors (Pkts)          0	0

Now I have nice snr margin. But nothing will change

I think I will stick on ADSL anyway, as 2/2+ doesn't give me anything extra on my line length.

Thanks for your help.

Nick

In reply to a post by yarwell:

What happens Friday ?

I mean lets see what I end up with Friday after 2 more early mornings of one disconnection.

Nick

right, if you restart that again and get 3072 then you are banded and being held down. The noise issue is not currently present. You should get a big speed increase from rebooting the modem from those stats.

3070-3072 at a guess

But it will not. It will sync at 3072/1 again. And then later after a few more disconnects in the morning, I will get 'capped' at 2500 or similar - and over a few days it just gets lower and lower. Even with those stats.

Do you understand what I mean now?

Nick

Edited by deleted (Wed 20-Feb-13 12:05:48)

well if it syncs again reliably at 3072 then its capped and you need the cap removing to go faster. Apart from your first posting that's the only set of stats with potential to go faster in the absence of a cap.

I haven't seen data showing a progressive reduction in the band you're on but the two above are 3328 - 6656 and 4864 - 9728 if any of those look familiar. The one below is 1152 - 2272.

Doesn't help us with the underlying issue that causes it to drop in the morning, but that's the best set of stats posted so far.

OK, thanks, but my question? Why if I do get a disconnect and sync slightly lower does that cap get put in place?

As Brian said in MP, "What chance do I have?" http://www.youtube.com/watch?v=0uMJYQ9LKGQ

Nick

OK, as my current stats on bog-standard ADSL are now:

Line Status:Connected
DSL Modulation Type:ADSL_G.dmt
Annex Type:Annex A
 	            Upstream	Downstream
Current Rate (Kbps)	928	3072
Max Rate (Kbps)	       1080	8608
SNR Margin (dB)     	10	24.5
Line Attenuation (dB)	22.5	41.5
Errors (Pkts)           0	0

I have called Etna support (who are really good, BTW) to get my line reset and the cap removed (again!), after checking my wires etc. (again), I have put a ferrite ring on my in-line telephone cable.

From today I will not touch the router at all, and lets see what happens 'automatically'

Thanks for everybody trying to help me here.

Nick

Edited by deleted (Wed 20-Feb-13 12:47:20)

Why if I do get a disconnect and sync slightly lower does that cap get put in place?

Pass. Perhaps it is set to the "extra stable" setting or something.

Usually the response to instability is to step up the SNR margin in steps of 3 dB which depresses the speed a little and gives lower error rates and a higher chance of hanging onto the line.

Does that Plusnet link say anything about when banding is used ?

added: I checked, it says "For lines which drop frequently, a banded profile can be applied, which will restrict a line's connection speed from connecting at a level which it can't maintain"

Edited by yarwell (Wed 20-Feb-13 13:06:25)

Line just reset - had to reboot the router, this time I set DSL settings to 'auto':

Line Status:Connected
DSL Modulation Type:ADSL_2plus
Annex Type:Annex A/I/J/L/M
 	             Upstream	Downstream
Current Rate (Kbps)	1131	8771
Max Rate (Kbps)	        1140	9324
SNR Margin (dB)	        6.6	3.8
Line Attenuation (dB)	22.4	42
Errors (Pkts)	        0	0

Lets see what happens now

Nick

margin dropped to 3.8 already - hmm. Personally I would be tempted to leave it on G.dmt in case the "event" that takes it out happens in the higher frequency bands - but it is a guess.

Fingers crossed !

That looks pretty good - let's hope you can hold the ADSL2+ connection with a current 3.8dB SNRM and there are not any significant noise events...

8288Kbps would be about right if you had a 6dB SNRM

You are right - been up and down like a yo-yo so far. BUT I am not going to fiddle any more, I will let the line sort itself out and see what happens.

NIck

Are there any settings in your router to stop "Annex Type:Annex A/I/J/L/M"? Just in case it is relevant, seeing as there is something very odd.

You want Annex A, as in when you got G.DMT.

I think it auto defaults to what ever the annex is (in our case A). But I have tried just setting 'annex A' also - makes no difference. Also remember I had exactly the same issues with my Cisco router.

BTW, things are worse now

Connection is up and down like a yo-yo, and I can't get much more than 700~1500kb download speed (even with those stats.

Been on the phone again, see what happens, but it looks like Etna will get an engineer out to check my line.

Nick

Edited by deleted (Wed 20-Feb-13 16:04:00)

I suggest using adsl2 (not adsl2+).

Locks down to the stronger frequencies only and you will get the advantages of adsl2 still. (except SRA which died when ukonline went out of existance).

In reply to a post by RobertoS:

Are there any settings in your router to stop "Annex Type:Annex A/I/J/L/M"?

I believe that is a red herring. It is just a copy-&-paste of a drop down list.

On my router (& I've seen it on others) for the ADSL Mode field I get:

ADSL mode AutomaticG.992.1 (G.DMT)G.992.3 (ADSL2)G.992.5 (ADSL2+)G.992.3 Annex-MG.992.5 Annex-M

when it is set to and displaying only "G.992.5 (ADSL2+)".

Yep, I done that a while ago as with 2+ it was up and down every 5 minutes, but with throughput of between 700kb ~ 1.3Mb

Been holding a connection OK now on adsl2 with ip profile of about 5 meg and 4500 download- this is what I used to get before all the trouble started.

Current stats:

Line Status:Connected
DSL Modulation Type:ADSL_G.dmt.bis
Annex Type:Annex A
 	              Upstream	Downstream
Current Rate (Kbps)	1055	6308
Max Rate (Kbps)         1048	6324
SNR Margin (dB)    	9.1	7.6
Line Attenuation (dB)	22.3	39
Errors (Pkts)	          0	0

I did get back to Etna though, and after all this trouble and all the things we tried, I am getting a BT engineer around to test my line.

Anyway, lets see what I have in the morning when I get up.

Nick

Got up this morning, and had two reconnections, one at 2:55 and one at 06:50. BUT, I was still sync'ed at 5950 and getting 5mb downloads! Then it went down again at 08:55 and sync'ed at a HIGHER rate! Hurray! This is how my line used to work. Current:

Line Status:Connected
DSL Modulation Type:ADSL_G.dmt.bis
Annex Type:Annex A
 	              Upstream	Downstream
Current Rate (Kbps)	1043	6166
Max Rate (Kbps)     	1044	6520
SNR Margin (dB)	        9.3	11.3
Line Attenuation (dB)	22.3	39
Errors (Pkts)	         0	0

Now, I still haven't heard from BT engineer (I got up early just in case). So, would an engineer check out my line external first before coming to my premises? It certainly looks like something got fixed.

Nick

you have an Openreach appointment booked ? Usually they are like 0800-1300 or similar slots, you did well to get one for next day.

In reply to a post by Lethe:

Line Status:Connected
DSL Modulation Type:ADSL_G.dmt.bis
Annex Type:Annex A
 	              Upstream	Downstream
Current Rate (Kbps)	1043	6166
Max Rate (Kbps)     	1044	6520
SNR Margin (dB)	        9.3	11.3
Line Attenuation (dB)	22.3	39
Errors (Pkts)	         0	0

Last night :-

Current Rate (Kbps) 1055 6308
SNR Margin (dB) 9.1 7.6

looks like you've edged up to a 9 or 12 dB SNR margin target. DLM noticed the instability.

I was told today, but never received a phone call back to confirm, so I do not know (but I still got up early JIC). But I reckon somebody is doing something on my line, as it just disconnected and resync'ed again at even a higher rate of 6182 @ snr 11.5.

It hasn't connected like this for months

Nick

Well, my connection since the two disconnects after 08:00 today is now perfect.

And believe it or not, I got a call from Enta that BT have been running diagnostics on my line this morning and they found 'nothing wrong'. Strange how it is now the best connection I have had for months, isn't it

But my quandary - engineer is booked for tomorrow - I have until 20:00 tonight to cancel.

What to do? Stand the risk of being charged if he finds 'nothing wrong' or cancel and hope my line has really been fixed mysteriously ?

Nick

Really you should be getting a stable connection with ADSL2+ on a 39dB attenuation with a 6dB SNRM - I reckon if you can not then a SFI engineer visit would be worthwhile...

In reply to a post by 4M2:

Really you should be getting a stable connection with ADSL2+ on a 39dB attenuation with a 6dB SNRM

It'll be a 42dB Attenuation on ADSL2+. Estimated 8 to 9 Meg Sync, as OP had once before.

Edited by XRaySpeX (Thu 21-Feb-13 12:26:35)

I would cancel - for the time being. Tell Enta that you want to "postpone it" which will keep their fault record open.

They might be nothing wrong now, but it could be that the diagnostics could have done something unseen. I have had 5 BT Tech visits (up to 5 hours long) and spent hours on the phone trying to resolve a problem that everyone could see. Finally, it just suddenly changed and the problem was solved. The BT staff are at a loss to say what they changed or did (and I believe them) and cannot identify any changes that have been made.

So, just keep monitoring for a week or two and then decide if you are happy.



And get a copy of Router Stats Lite and have that running with very frequent (10 second) sampling for the next week. That will show what the SNR is just before any disconnect.

Edited by MHC (Thu 21-Feb-13 12:32:53)

In reply to a post by XRaySpeX:

In reply to a post by 4M2:

Really you should be getting a stable connection with ADSL2+ on a 39dB attenuation with a 6dB SNRM

It'll be a 42dB Attenuation on ADSL2+. Estimated 8 to 9 Meg Sync, as OP had once before.

Yes previous line stats did indicate 42dB with ADSL2+ but so did a ADSL_G.dmt
stat also, i.e. 41.5dB on Wed 20-Feb-13 11:57:17

In reply to a post by MHC:

I would cancel - for the time being. Tell Enta that you want to "postpone it" which will keep their fault record open.

~~snip~~

So, just keep monitoring for a week or two and then decide if you are happy.

And get a copy of Router Stats Lite and have that running with very frequent (10 second) sampling for the next week. That will show what the SNR is just before any disconnect.

Yes, if all looks good about 18:00 tonight I may well postpone the visit and monitor over the next week or so. I am still intrigued BT 'diagnosed' my line and then it all of a sudden is 'better'. We shall see.

As for Router stats, alas I am 100% GNU/Linux systems here (since about 2002), and I doubt my new ADSL modem/router will work with it anyway - the telnet interface has very little options, and the web interface is all javascript in frames.

The adsl modem/router, btw is excellent, 100% fault free and excellent wireless and features:

http://www.tp-link.com/en/products/details/?model=TD...

...except you cannot turn NAT off

Nick

RSL works with the TD8960/61 so you could try that or using te custom option you can tweak it.

There is also a discussion page on how run it under Linux http://forum.kitz.co.uk/index.php?topic=1716.0


Don't get too hung up with the "Diagnosed and suddenly all is sorted" and believing someone is not telling the full story. It happens a lot in comms, for example a punch down connection (IDC) may not be perfect and the BT Tech starts to try and find out why ... he inserts the test jack into the Krone strip and all appears correct and the fault has disappeared. What happened was that inserting the jack sorted the IDC issue. Or, your profile has been downloaded and then part of that promulgated through various systems. One system got a small corruption - say just two bits wrong and it caused problems. During diagnostics they load test data and no fault found, so your data is reloaded and this time, all is correct. Problem gone - but no one knows exactly why.

Unfortunately RSL does not work with this adsl modem/router - looking at the web page interface, it is produced using 'on the fly' js with a back end web sql DB, so no matter what I tried RSL couldn't see the data - just the js code.

OK, so your explanation re BT doing diagnostics does sound true - so I wonder if something got changed around Sept/Oct last year, interferring with my line somewhere, and the fault was missed after all this time?

I do appreciate that sort of error though - a few years back when I was an employed IT guy, one user kept on complaining he had to reboot 2 or 3 times to get his machine on the network. After a lot of tests, I decided to run a straight Cat5 to the router... and all was well. Tracing the existing floor box connection, whoever laid the carpet had pinned the cable tray right through the middle (and that floor box cable) - and sometimes it must have shorted out, other times it didn't.

Nick

In reply to a post by MHC:

I would cancel - for the time being. Tell Enta that you want to "postpone it" which will keep their fault record open.

They might be nothing wrong now, but it could be that the diagnostics could have done something unseen. I have had 5 BT Tech visits (up to 5 hours long) and spent hours on the phone trying to resolve a problem that everyone could see. Finally, it just suddenly changed and the problem was solved. The BT staff are at a loss to say what they changed or did (and I believe them) and cannot identify any changes that have been made.

So, just keep monitoring for a week or two and then decide if you are happy.

Been up great all day since the 'diagnostics' this morning (at perhaps my best sync rate/speed ever), and have taken your advice - I do not want a bill for 'no problems found' now.

Thanks for your (and everyone else's) help.

Nick

it's reporting "line attenuation", the "signal attenuation" is probably very similar.

I'm with AOL and I noticed similar in mid November last year.
So far in the last month, BT have re-routeed my line, BT broadband said the line is perfect and then couldn't get it to work!
The line gets reset at odd times (once whilst on the phone to AOL!!)

I've tried 3 different router/modems and just bought a brand new asus - strange but no difference.
I get a better rate using a 3G dongle.
I've just given up for the time being I really can't be bothered.

Well been up for 24 hours now, no disconnects and still a nice fast connection @ 6182 with d/l speeds of around 5.5mb.

So that goes to prove sometimes there are issues on the line that BT refuse to believe for some reason or other until you can actually get them to do something.

I am glad I cancelled the engineer today now

Nick

Well, my line is still playing up - and routerstats didn't work, but if you are interested, I hacked my own 'stats' script:

http://forums.thinkbroadband.com/linux/t/4214138-tp-...

So I can keep check now.

Nick

Well, I need to get an engineer I suppose. Since Thursday 21st I have had 4 disconnects, and each time on re-connection my SNR margin goes up, my sync speed goes down, and IP Profile and max line speed goes down.

I am currently sync'ed at 3096 with SNR margin of 19.6 and line max speed 4mb with a IP profile of 2.71.

Interestingly enough I was running a measure on my router over night - it disconnected at 09:50 today. There was no drop in SNR (it was at 9.1/13.2) so I dunno what is causing it.

Nick

I am currently sync'ed at 3096 with SNR margin of 19.6

Should speed up on a resync, as 19.6 isn't a target margin and 3096 isn't a banded profile speed ?

It wouldn't - just used to re'sync at 3092(ish). Anyway, engineers just left

FULL REPORT TO FOLLOW

Nick

Edited by deleted (Wed 27-Feb-13 13:30:39)

Well, the BT engineer called. I cannot divulge his name, but let's call him MC.

He was truly brilliant - nothing like the horror stories I read about BT engineers at all.

MC first called me on my mobile to let me know he was arriving in about 15 minutes. He did.

MC then disconnected all my stuff, and done some tests with his gear. I had a bad line.

MC then replaced the face plate, done same tests - bad line. He told me the equipment showed him there was a fault about 120 metres away indicating the green box (now painted grey).

He then went outside to the green box (now painted grey) for an hour.

MC said he think he found the issue, and proceeded with all the tests again. This time they passed,. but MC said he wasn't happy as my line should be better.

MC then said I will go outside again and check.

15 minutes later MC returned and said he will try something else.

He re-wired my phone line to use two different wires (i.e. my face plate now has the ground and ring bell wires connected).

MC done the tests again. All passed with flying colours

So all along, it was so fault in my line between the box outside and the green (now painted grey) box up the street,

Here is my stats graph - a bit busy:

http://linicks.net/stuff/stats.png

A little improvement, don't you think?

Nick

Edited by deleted (Wed 27-Feb-13 18:40:50)

Sorry to go on... but I am still hanging on this super speed even at lowly SNRM. Never, ever had such a good connection:

ine Status:Connected
DSL Modulation Type:ADSL_2plus
Annex Type:Annex A/I/J/L/M
 	            Upstream	Downstream
Current Rate (Kbps)	1023	9664
Max Rate (Kbps)	        1024	9665
SNR Margin (dB)        	6.8	0.4
Line Attenuation (dB)	22.2	42
Errors (Pkts)            0	0

Nick

Don't like the low NM. Discon could be imminent.

Nope, stayed up all night, no disconnects! The lowest SNRM up got was 0.4!

Nick

I thought it was tailing off on the graph, at least it's hanging in there.

It virtually hit 0, but the connection hung on in there.

Here is the full graph from over night:

http://linicks.net/stuff/stats1.png

Remember, it is all on the same scale, so what a difference since the line got repaired!

Nick

Edited by deleted (Thu 28-Feb-13 10:38:07)

well previously you had higher snrm so its hard to see if was a huge actual improvement. Because when the sync speed went up the snrm also went down.

Well, I know that I never, ever connected above 7mb before in 8 years on this line!

Anyway, after being connected at that rate for 48hours (and SNRM dropping down to 0.2 sometimes!), the line just dropped and reconnected:

Line Status:Connected
DSL Modulation Type:ADSL_2plus
Annex Type:Annex A/I/J/L/M
 	            Upstream	Downstream
Current Rate (Kbps)	1051	8384
Max Rate (Kbps)	        1052	9016
SNR Margin (dB)	         5.8	8.1
Line Attenuation (dB)	22.2	42
Errors (Pkts)	        0	0

I guess this is the DSLAM doing it's stuff over my 10 day training period.

I am still well happy though - never had such a good connection

Nick

In reply to a post by Lethe:

...He re-wired my phone line to use two different wires...

Looks like changing the pairs did the trick - your line is performing really well now

In reply to a post by Lethe:

I guess this is the DSLAM doing it's stuff over my 10 day training period.

Its stuff being reconnecting when it senses router has discon'ed when NM no longer tenable. Nowt to do with training but normal operation.

Still your stats are good and let's hope it don't keep dropping NM too low.

Rather than read all the threads, here is a final summary.

My line kept losing sync, and subsequently I got 'capped' at a lower and lower sync rate/high SNRM. This started around Sept./Oct. last year.

After a lot of messing about, including buying a new modem/router my ISP (Enta) called out an engineer.

He found my line was bad, and ended up swapping the pair of wires from the box in the street to my faceplate - this sorted the problem - I now have a solid connection and good speed.

I was sync's at around 9600 for 48 hours but SNRM was between 6 down to 0.2! The line dropped and I resync'ed at 8400 with SNRM of 8 down to 6 This seems rock solid now.

Here is the latest noise stats polled from 11:45 1 Mar. to 09:30 2 Mar. In the chart I have added 3 'spikes' - these indicate the times of a) Sunset, b) Midnight, c) Sunrise.

www.linicks.net/stuff/noise.png

Nick

I don't know, as it sync'ed around 11:30 in the morning when my SNRM was around 6. It was almost 48 hours since connection was up after line repair, so I do think it was the hardware sorting out the negotiation to bring the SNRM up so I don't drop below 6dB now.

Nick

That looks about right for the SNR graph - around 2dB swing from daylight to overnight, a lot of lines will actually have more than that.

Spoke too soon Just had another re-sync - funnily enough around the same time as yesterday. I switched back to ADSL2 only now:

Line Status:Connected
DSL Modulation Type:ADSL_G.dmt.bis
Annex Type:Annex A
 	              Upstream	Downstream
Current Rate (Kbps)	1043	6751
Max Rate (Kbps)	        1040	7328
SNR Margin (dB)	        5.6	11.7
Line Attenuation (dB)	22.2	39
Errors (Pkts)	        0	0

Still, I am still happy with the speed etc. Lets hope it is more stable now.

Nick

Funny it's re-syncing twice round midday. Would expect it more at night.

In reply to a post by Lethe:

Spoke too soon Just had another re-sync - funnily enough around the same time as yesterday.

Did you happen to notice what the sync time downstream SNRM was?

No, I wasn't monitoring - but I am not too worried, as it is still the best connection I have had on this line.

Anyway, I will leave things as they are for a few days, then I will revert back to my Cisco 850 modem/router now I now it wasn't that causing the issue.

Nick

Hopefully your current ADSL2 connection will hold with a downstream SNRM of ~12dB

I give up

So since engineer visit wednesday, I got disconnected:

Thursday NONE
Friday @ 11:45(ish)
Saturday @ 11:30(ish)
Sunday @ 10:20(ish)
Today (Monday) @ 06:30(ish)

I am back on banded profile (4mb). So I switched back to my Cisco 857 (as it wasn't that causing the issues). Here is my latest stats since 8:33 this morning:

Modem Status:	 Showtime (DMTDSL_SHOWTIME)
DSL Mode:	 ITU G.992.5 (ADSL2+) Annex A
~
Capacity Used:	 46%				 100%
Noise Margin:	 13.5 dB			  6.0 dB
Output Power:	 19.5 dBm			 12.5 dBm
Attenuation:	 38.0 dB			 20.0 dB
~
 		 DS Channel1	  DS Channel0	US Channel1	  US Channel0
Speed (kbps):	          0	        4544	         0	        1184
Cells:		          0	     3293079	         0	    75847772
Reed-Solomon EC:          0	           0	         0	           0
CRC Errors:	          0	         158	         0	           0
Header Errors:	          0	          61	         0	           0

Am I correct that the 'banded profile' gets automatically removed if I stay in sync for 3 days?

Nick

Edited by deleted (Mon 04-Mar-13 16:23:45)

Don't give up! Probably best to chase it up again with your ISP and check out what's going on...

Dropped connections, currently downstream SNRM 13.5dB, 4544Kbps sync, 38db attenuation on G.992.5 (ADSL2+) Annex A - it ain�t looking good

I will give them a call again in a few days - but now I am back on the cisco kit, it seems to report more 'real' data. The TP-Link router showed no connection errors - but the Cisco does.

And just watching the d/l SNR is worrying me - it swings from 19dB to 13 dB (on the current connection) in seconds (and anywhere in between).

I am getting worried now, as I live in a small block of flats, it might be the neighbours fridge or something that is causing the issue as the wire seems to run down through the wall in the stairwell close to all the other 3 flats under me.

NIck

P.S as to my connection 'banded profile' - does that get auto-reset after 3 days?

Edited by deleted (Mon 04-Mar-13 17:36:25)

Guess the neighbour's fridge could be causing a noise issue...

Banded profile: all I know is that for lines which drop frequently, a banded profile can be applied, which will restrict a line's connection speed from connecting at a level which it can't maintain - and sorry, I don't know about an auto-reset after 3 days, others on this forum may know or check with your ISP.

Just had another disconnect at 14:33... and result is:

Download speedachieved during the test was - 1.99 Mbps
 For your connection, the acceptable range of speeds is 0.8 Mbps-2 Mbps.
 IP Profile for your line is - 2 Mbps

I really do give up.

Nick

Is the phone working OK in the test socket? If so can you hear any noise on the line when using a corded phone (quiet line test: dial 17070.)

Sometimes very slow speeds can be caused by poor conductivity along one of the wires which form the incoming copper pair. In some cases the broadband may just about work but the phone does not...

Yes, all is fine - remember I had a BT engineer around last weds. he found a fault and fixed it, plus I got a new filter face plate in the deal.

I have plenty of cat5 lying around. Time to hang myself

Nick

In reply to a post by Lethe:

remember I had a BT engineer around last weds. he found a fault and fixed it

Yes he fixed it, but things seem to have deteriorated again since then - definitely time to chase up the ISP and report that the problem has reoccurred. Voice line is OK so it's certainly a broadband issue of some sort...

OK, after a long call to Enta techies (who have been very good, can't praise enough), it turns out this is the issue:

My line was bad, which the BT engineer fixed - but even after this, on ADSL2+ the DLM was seeing 100's of errors on the line a day - at my end I didn't see many (if any) errors at all except the one disconnect/resync randomly about every 24 hours.

Now, due to the way the DLM management software works on ADSL2+, due to all the errors it saw, every time I got a disconnect, it upped my SNR and stuck me on a 'banded' profile (nothing to do with ip profile). Thus the DLM still saw all these errors every day, so subsquently every disconnect/resync/reboot it implimented a higher SNR lower 'banded' profile to try to make my line stable.

Well, of course, all the time the errors persisted, I got a slower, and slower connection. Chicken and the egg situation.

Now it is only ADSL2/2+ that the DLM uses 'banded' profile to try to stablise the line - so now we are trying bog standard ADSL - so even if I do get a disconnect, I should be able to resync at whatever the line can do at that precise time (or a reboot during the day to get the speed up, etc.).

To change over to ADSL is a 24 hour process, but it happened at 02:21 this morning. Current stats:

Modem Status:	 Showtime (DMTDSL_SHOWTIME)
DSL Mode:	 ITU G.992.1 (G.DMT) Annex A
~
Capacity Used:	 100%				 99%
Noise Margin:	  8.0 dB			 11.0 dB
Output Power:	 18.5 dBm			 12.5 dBm
Attenuation:	 38.0 dB			 21.0 dB
~
 		 Interleave		Fast	Interleave		Fast
Speed (kbps):	          0	        7392	         0	         960
Cells:		          0	     1025737	         0	    46447242
Reed-Solomon EC:          0	           0	         0	           0
CRC Errors:	          0	         251	         0	           0
Header Errors:	          0	         203	         0	           1

I am keeping my eye on the CRC/Header errors, but they don't look too bad since 02:21 hours.

Nick
EDIT - BTW, forgot to say, before I went to bed last night, I hard set the Cisco router to sync using ADSL (itu-d.gmt) and there is a dsl command 'dsl noise-margin n', when 'n' is the range 3 ~ -3. I set this to '3' so that forces the router to sync 3dB higher than normal. So far appears OK.

Edited by deleted (Wed 06-Mar-13 09:34:09)

It appears to be on Fast Path - interleaving is normally the first thing to do if it's clocking up errors. May be worth a try.

Well (we have been here before) all looks good at the moment, so I will not touch *anything* to see how it goes.

I am polling my router stats (I will post graph later), and SNR looks the best for ages - as to the errors, they are clocking up slowly, but nothing to worry about, I think:

Interleave		Fast	Interleave		Fast
Speed (kbps):	          0	        7392	         0	         960
Cells:		          0	     2694769	         0	    75566610
Reed-Solomon EC:          0	           0	         1	           0
CRC Errors:	          0	         819	         2	          22
Header Errors:	          0	         703	         5	          21

So that is about 650 CRC errors, and 580 Header errors in 4 hours since I have been monitoring.

Nick
EDIT - to be honest, just checking, the errors do not seem to affect my line at all - I am getting a good through-put:

~ $ wget http://ipv4.download.thinkbroadband.com/200MB.zip
--2013-03-06 11:53:48--  http://ipv4.download.thinkbroadband.com/200MB.zip
Resolving ipv4.download.thinkbroadband.com (ipv4.download.thinkbroadband.com)... 
Connecting to ipv4.download.thinkbroadband.com (ipv4.download.thinkbroadband.com)|...
HTTP request sent, awaiting response... 200 OK
Length: 209715200 (200M) [application/zip]
Saving to: `200MB.zip'

100%[======================================>] 209,715,200  782K/s   in 4m 24s 

2013-03-06 11:58:11 (777 KB/s) - `200MB.zip' saved [209715200/209715200]

Edited by deleted (Wed 06-Mar-13 12:02:32)

Looks like interleaving is still not being applied - possible error with the page formatting of the latest stats posted on this site.

Throughput does look good: 777KB/s (6216Kbps)

Probably a noise source affecting the ADSL2+ frequencies, but ADSL1 will hopefully be more stable with a downstream ~9dB SNRM

No I am not on interleaving - I am just leaving the line as is at the mo, and see what happens.

Yes, the post got garbled - the column headers need moving along so the last 'fast' is over the last column.

The techie did say that there must be some other issue on my line that ADSL2+ cannot handle, hence the reason to test again on ADSL after the BT engineer *repaired* my line (remember, before the *repair*, I was still getting issues/disconnects/resync's with ADSL).

Anyway, I don't get much more on ADSL2+ anyway, and 6mb is fast enough for me (and I still have a decent upload figure)

Nick

In reply to a post by Lethe:

Anyway, I don't get much more on ADSL2+ anyway, and 6mb is fast enough for me (and I still have a decent upload figure)

OK, if you are happy with that, then fair enough.

However, personally, I would always be concerned about an underlying line fault and until the line was stable on ADSL2+ (8640Kbps, 6dB SNRM on a 41dB downstream attenuation) I wouldn't be 100% happy...

Post deleted by yarwell

Well, sometimes beggars can't be choosers if you like.

Years ago when I had ADSL first installed, it was great - super fast and stable as anything - I think I used to sync at around 7900. Then about 6 years ago(?) some JVC idiot up the road whilst digging up the road cut through the phone cables, disconnecting my street and several others around me. It took BT about 4 days to repair everything, and since that time, I could usually only sync at about 5400. So what I have now (if it lasts ) is better than I had.

And also, I doubt BT would dig up the roads etc. just to fix my line

Nick

Best of luck with ADSL1

It's getting better... seeing as SNR was pretty stable, I changed the Cisco 'dsl noise-margin' option to '2' (forces modem to sync 2dB higher, I did set it at '3'):

Modem Status:	 Showtime (DMTDSL_SHOWTIME)
DSL Mode:	 ITU G.992.1 (G.DMT) Annex A
~
Capacity Used:	 100%				 97%
Noise Margin:	  6.5 dB			 11.0 dB
Output Power:	 19.0 dBm			 12.5 dBm
Attenuation:	 38.5 dB			 21.0 dB
Defect Status:	 None                            None                        
~
 		 Interleave		Fast	Interleave		Fast
Speed (kbps):	          0	        7808	         0	         896
Cells:		          0	     1041276	         0	     8022634
Reed-Solomon EC:          0	           0	         0	           0
CRC Errors:	          0	          25	         0	           0
Header Errors:	          0	          15	         0	           0
~
			ATU-R (DS)	ATU-C (US)
Bitswap:	       enabled		  enabled
Bitswap success:          0	              0
Bitswap failure:          0	              0

I done this 1 hour 10 minutes ago - errors are now a LOT lower, and sync speed increased slightly.

Nick

Keep an eye on the reported downstream SNRM if there are no re-syncs this evening or over-night - I wouldn't like to see it drop to below 3dB after sunset.

Error rates look minimal at the moment

Yeah, I am going to monitor until about 21:00 tonight. The graph makes interesting reading, so I will post it here later.

But finally it really looks like my line is fixed. I was wondering if BT done something when I got reset, as Enta said it takes 24 hours, so I should have had a reset around 15:00 today, but it happened at 02:21 this morning - I wonder if they changed something on my physical wires?

Nick

UPDATE

Noise Margin:	  6.5 dB			 11.0 dB
Output Power:	 19.0 dBm			 12.5 dBm
Attenuation:	 38.5 dB			 21.0 dB
~
 		 Interleave		Fast	Interleave		Fast
Speed (kbps):	          0	        7808	         0	         896
Cells:		          0	     1363345	         0	    15397184
Reed-Solomon EC:          0	           0	         0	           0
CRC Errors:	          0	          56	         0	           0
Header Errors:	          0	          39	         0	           0

This is after 2 hours on 'dsl noise-margin 2' - that's more like it

Edited by deleted (Wed 06-Mar-13 16:24:02)

In reply to a post by Lethe:

I wonder if they changed something on my physical wires?

Must have been OR working on night shift LOL!!!

In reply to a post by 4M2:

Must have been OR working on night shift LOL!!!

To be honest, that might be as strange as it sounds. They must have engineers working overnight in the exchanges sometimes doing upgrades or whatever, and I know from experience that sometimes the job gets dome quicker than thought - so rather than sit around for a few hours, you find something else to do...

Nick

The mysteries of what happens exchange side of one's NTE5 never cease to cause amazement

OK, time to put this thread to bed.

Bad line - engineer called and fixed.

On ADSL2/+ still get errors (but not seen my end). DLM does see errors and kept increasing SNR/lowering 'banded profile' to try to make line stable on every disconnect/reboot et al. DLM still sees more errors and does same again. Ad infinitum...

Got ISP to reset excahnge to just ADSL. Forced my Cisco router sync at 2dB higher. Now d/s SNR hovers around 8.5/~10/5. Stable.

Stats:

Modem Status:	 Showtime (DMTDSL_SHOWTIME)
DSL Mode:	 ITU G.992.1 (G.DMT) Annex A
~
Capacity Used:	 100%				 99%
Noise Margin:	  9.0 dB			 11.0 dB
Output Power:	 19.5 dBm			 12.5 dBm
Attenuation:	 38.0 dB			 21.0 dB
Defect Status:	 None                            None                        
Last Fail Code:	 None
Watchdog Counter: 0xBA
Watchdog Resets: 0
Selftest Result: 0x00
Subfunction:	 0x00 
Interrupts:	 45502 (0 spurious)
PHY Access Err:	 0


 		 Interleave		Fast	Interleave		Fast
Speed (kbps):	          0	        7040	         0	         960
Cells:		          0	     5576576	         0	    40418243
Reed-Solomon EC:          0	           0	         0	           0
CRC Errors:	          0	         500	         3	          14
Header Errors:	          0	         380	         4	           5
Total BER:		  0E-0		 1206E-9
Leakage Average BER:	  0E-0		 2243E-9
			ATU-R (DS)	ATU-C (US)
Bitswap:	       enabled		  enabled
Bitswap success:          0	              0
Bitswap failure:          0	              0

Summary: My line is poor, and cannot handle ADSL2/+ for whatever reason.

Now, why this happened at around Sept/Oct last year I do not know.

Nick

adsl2 is more robust than g.dmt, although adsl2+ most defenitly can be worse on poor lines.

However people often find adsl1 works better and I believe that to be down to equipment been able to deal with adsl1 better whether its the modem, dslam or both in combination.

I know when I tried the netgear dg834 and speedtouch 585v6 both were better on adsl1 than adsl2.
When I was on ukonline and used a bilion router (matched up to chipset on dslam) that worked very well on adsl2 but adsl2+ gave a poor sync speed.

If the line is dodgy I wouldnt even try adsl2+ at all, and if adsl2 is also poor in your experience then just stick with adsl1.

Also certian routers will drop sync much easier than others. I have used routers that will hold onto sync even in the situation of no useable data been transmitted due to very severe errors, but I have also used routers that drop sync whenever I sneezed. You also have to look at your snrm swing, eg. if your snrm drops 6db every night and you sync at 6db in the day then that is not going to hold, as well as snrm movements during any noise bursts you may have.

In reply to a post by Chrysalis:

adsl2 is more robust than g.dmt, although adsl2+ most defenitly can be worse on poor lines.

Yes, but ADSL2 still has that DLM thing going on so that if you do have errors on the line, it tries to make it stable and then you just get lower and a worse profile on every disconnect/resync.

BUT I just had another disconnect - and this time was running polling on the router and caught it! The first time seen in history (where's David Attenborough to narrate this event when you need him?).

The graph:

www.linicks.net/stuff/THE_END.png

To read the graph, polling been running since 14:11. The first down spike (3.5dB) was the disconnect at 262 minutes since 14:11 - I was watching air TV and heard the Cisco router *click* as it reconnected (they do that).

So next, I connected to router, shutdown ATM interface, reset the forced sync +2dB I was trying (obviously doesn't work) to 0 (i.e. default mode), and reloaded; the big spike is the *gasp-of-death*, I think, and the next 3.5 dB spike is reload.

BUT, at least I reconnect now at either slightly slower/faster than before instead of the stupid DLM trying to make my line stable and slower.

I have a fault on the line, that is for sure now. So no more on this.

Thank you everybody for input and feed-back.

Nick

BTW, I have got something out of this - learning the [censored] super http://www.gnuplot.info/ to produce the graphs from my router stats