topic Re: DLM reset request (ADSL2+) in Broadband

DLM reset request (ADSL2+)

Mardler — Sat, 05 Oct 2024 13:02:58 GMT

Long power outage yesterday.

A Billion 7800DXL always handled cuts superbly before but this time it was killed possibly by the switch on surge.

Am using an old PN Technicolor582. It does the basics but is very slow. Stats say bandwidth is 16.1 but Ookla over wi-fi on an iPad gives 3 maximum. SNRM is shown as c.12. This was OK with the Billion as it gave a rock solid connection of 16+ and 13+ over wi-fi/iPad.

Can PN reset the DLM to 6?

TIA.

Re: DLM reset request (ADSL2+)

Anonymous — Sun, 06 Oct 2024 09:30:11 GMT

@Mardler

Have you confirmed that you do not also have a fault on your line?

For example, if you still have a telephone service, do you have dial tone?

It is quite possible, (I have experienced it myself), for one leg of the telephone pair to be broken, which will prevent the telephone from working, but for the broadband to still work - albeit at greatly reduced speed.

Re: DLM reset request (ADSL2+)

Baldrick1 — Sun, 06 Oct 2024 10:30:40 GMT

@Mardler

Your message is a bit confusing.

Are you saying that you previously got with the Billion a download of 16Mbps with a SNR of 12dB and with the 582 you are receiving the same 16 Mbps with the same SNR. The only difference being that now the wireless performance is much slower?

If so, then this is a wireless problem and nothing to do with your ADSL connection.

Why not either ask Plusnet for a new hub or buy a replacement for the Billion.

At 16Mbps you are getting nearly the full speed available from ADSL so I doubt that a reset would make a significant difference anyway. I would guess that your wired speed exceeds the guaranteed minimum. The line doesn't need a low SNR and in these circumstances it's advantageous to have it higher.

Re: DLM reset request (ADSL2+)

Mardler — Sun, 06 Oct 2024 14:34:17 GMT

Mr P: the phone line is fine.

Re: DLM reset request (ADSL2+)

Mardler — Sun, 06 Oct 2024 15:01:45 GMT

Baldrick: thanks and yes, that is exactly what I mean. I am also aware of the lousy wi-fi performance of the 582 hence buying the Billion 7 years ago. The Billion gives both a maximum possible (bandwidth) and actual connection, the 582 gives only the former so connection is probably going to be 80% of that at best. Last night late streaming YT stuff was very blotchy thus confirming 3 devices showing 2 or 3 Mbps d/l over wi-fi (another device gave 11+ which was odd) all using Ookla.

The Billion SNR tweaking initially allowed a solid 20Mbps but shoddy work at the exchange caused all kinds of problems for those relying on it. Eventually the SNR started to rise until its current level so I didn't tweak it instead opting for a medium d/l speed and better resilience and it's worked perfectly until now.

I just bought a replacement 7800DXL from a guy who seems honest and helpful.

I will post again if I manage to get the replacement working.

Re: DLM reset request (ADSL2+)

Townman — Wed, 09 Oct 2024 14:37:20 GMT

SNRM of 12dB suggests that there is an (or has been an) issue on line. Suggest that raising a fault report can do not harm.

What is the line attenuation figure? With 16mbps at 12dB on ADSL2+ this sounds like a very short line ... which might do lots better.

WiFi is though going to be limiting here.

Re: DLM reset request (ADSL2+)

Mardler — Thu, 10 Oct 2024 12:32:02 GMT

An update.

The DLM request was when using the Technicolor router.

A replacement Billion 7800DXL arrived yesterday. I first tried the supplied psu with my 7800 and it worked perfectly.

It too connected with a high SNRM. The router target SNRM was 4 (which has given a rock solid connection with a high actual SNRM of 11+ and a lowish rate (which I left) so I reset it to 6.

The 6 setting gave a rate of 20379 with 17.1 measured over wi-fi. Stable all afternoon and evening.

Overnight the disconnects started. Very similar to several occasions last year (then the connection was mostly up for 2 or 3 months before a spell of hourly disconnects).

Last year, although Openreach wouldn't admit it, there was a fault at the exchange subsequently corrected.

Is it worth asking PN to run a check on my line?

Re: DLM reset request (ADSL2+)

Mardler — Thu, 10 Oct 2024 12:56:22 GMT

While typing my update comment there was another disconnect, "ADSL link down" as usual.

Simultaneously a mains monitor disconnected from the sender in the outside meter box.

Interference?

Re: DLM reset request (ADSL2+)

Mardler — Thu, 10 Oct 2024 13:41:24 GMT

TM, here are the stats:-

Target SNRM set at 4 at 16:46 yesterday:-

SNRM: 6.4, attenuation 16db, d/l rate (sync): 20379 (17.1Mbps over wi-fi).

Target SNRM set at 6 at 01:30 today:-

SNRM: 9.1, attenuation 16, sync 18603

Currently:- 8/17/13507*

We're about 0.7 of a mile from the exchange.

*The drop in sync rate coincided with the disconnects.

Wi-fi is pretty good.

Re: DLM reset request (ADSL2+)

Townman — Thu, 10 Oct 2024 15:45:02 GMT

I highly recommend that (at least whilst there are issues) you do not “game” the SNRM. All that does is to mask issues … and artificially keep the speed above the minimum guaranteed.

There is no harm in raising a fault … but only when the line management is not being fudged.

0.7km should deliver an attenuation around 12dB … which ought to sync at 24mbps (IP profile around 21mbps). So remove the fudge factor and get the underlying issue investigated, as it would appear that the line cannot sustain a 4dB margin.

Re: DLM reset request (ADSL2+)

Mardler — Thu, 10 Oct 2024 16:59:44 GMT

Read my notes again, TM.

There no fudge. The SNRM target is now set to 6. Apart from these odd spells the line easily sustains a 4db SNRM for months on end (e.g. 77 days, 90 days etc) in fact it has worked perfectly at 2. That's down to the router.

I also showed the attenuation at 16/17db (the Techicolor router was identical) which is way more than 12.

As for sync, I have never seen anywhere near 24mbps, 21+ is the best which is what I expect from a good line with the IP profile; 21220 held yesterday afternoon at 4db target SNRM until the early hours today when the disconnects started and I reset to 6 for greater stability but it made no difference.

Currently it's SNRM 8.1, attenuation 17, attainable rate 11520, sync 10467 - last disconnected 1h 30m ago. Not good!

Last year there were 3 or 4 spells of identical behaviour all due to an exchange issue.

Disconnects every hour or so are unacceptable.

We can soldier on a little longer before switching to FTTP. And there's the dilemma: who with?!

Re: DLM reset request (ADSL2+)

Mardler — Thu, 10 Oct 2024 17:43:11 GMT

I have been looking at the SNRM settings. Even at a target of 3 sync is 11900 (on 12980 attainable with actual SNR 6) which is crazy. Yesterday it was 20379 at 4 (21220 attainable, actual SNR 6.4). Resetting to 6 gives SNR 9+ and sync c.9. Attenuation is increasing, now 17.

This is near identical to 2023 and previous years when exchange faults were detected.

It doesn't explain why a mains monitor lost sync with its outdoors transmitter at exactly the same time as the internet connection once again became iffy. Maybe coincidence, or interference.

Re: DLM reset request (ADSL2+)

Anonymous — Thu, 10 Oct 2024 17:56:00 GMT

@Mardler

Are you in a particularly rural location?

I'm just wondering if there is an issue with your incoming mains supply. Possibly an occasional spike that is affecting your mains monitor, and also either your router or inducing interference on to your telephone line?

Re: DLM reset request (ADSL2+)

Mardler — Fri, 11 Oct 2024 02:53:17 GMT

Mr_P, thanks: locale is fairly rural and only 0.7 of a mile from the exchange. A mains transformer is very close to the house. So we should do better and were on Wednesday afternoon and evening up to just gone midnight.

I will try resyncing mid afternoon with the target SNRM set as before.

FWIW, the incessant disconnects started 10 or more years ago. A number of serious copper line faults were rectified with some improvement. The PN router was ditched for a top Netgear and that was a bit better especially wi-fi. Eventually I became fed up with often near dialup speeds and in 2017 bought the Billion. Instant success: we had an excellent speed and a 100% stable connection even using a somewhat dubious SNRM tweak (actual SNR of 3 or even 2). I used a more realistic SNRM long term and apart from bouts of disconnects like this the connection stays up for months.

Of course, we currently have strong solar activity so that might have an impact somewhere. Oh and I might wander round the locality listening for AM interference at c.512m which is roughly the frequency at which interference will affect the copper line and SNR.

Re: DLM reset request (ADSL2+)

Townman — Fri, 11 Oct 2024 06:37:02 GMT

I had read carefully your previous posts and your last one confirmed what I said before - you gaming the SNRM masks the issue. If your line is 0.7km it should do much better than it is doing without fudging things. If the line is fine, is fine the DLM will find its own way to 3dB without your “assistance”.

SNRM is only elevated to address stability issues, due to a fault. Your best course of action is to stop trying to bend light and raise a fault report. Confirming the line attenuation figure (which is more accurate than suggesting a line length) would help to affirm the assessment.

Re: DLM reset request (ADSL2+)

Anonymous — Fri, 11 Oct 2024 07:07:30 GMT

@Mardler

"We're about 0.7 of a mile from the exchange."

Just a thought, but how are you measuring that distance?

Is it the shortest distance by road from your house to the exchange, or do you have knowledge of the Openreach network topology? (ie from working for or speaking to Openreach, or being a rural area, are all the cabes clearly visible above ground on poles?

As an example, at a previous house, we were also much less than a mile from the exchange, by road. However, I discovered that to get to us, the cable from the exchange went past our house to the cabinet over 400 metres further up the road. The cable from the cabinet to the pole across the road from us added another 400 metres or so.

The net effect being that "our" telephone pair back to the exchange, (we also had ADSL then), was over twice the "direct path" length.

When that was taken in to account, the speeds we were getting made a lot more sense!

Re: DLM reset request (ADSL2+)

wcw — Fri, 11 Oct 2024 11:07:21 GMT

Feel free to ignore, but 'mains interference at midnight' suggests two somewhat obscure things to me.

1 - Someone has a 'whole house storage heater' on the same phase circuit as you, and it turns on at midnight and could (as experience) bring the mains down out of limits.

If **AND ONLY IF** you are confident with handling mains SAFELY, try measuring the voltage during 'problems'.

My parents observed input at 205V - out of spec. Reported to SSE and a bigger transformer was installed - although it is not happy with 100A hanging on just one phase even now. You can hear it 'singing' in the night.

2 - Recent auroral activity ? A long overhead line might be getting bothered.

Bill

Re: DLM reset request (ADSL2+)

Baldrick1 — Fri, 11 Oct 2024 13:08:42 GMT

@Mardler

In order tto get to the base performance of your line you need to stop your manual adjustment of the SNR and rebooting of the hub of your choice. Without this base information it is impossible for Plusnet/Openreach to remotely determine accurately how your line is performing.

Unfortunately this may require you to accept poor performance for a week or so. It might also be instructive to run a DSL monitoring programme, see https://kitz.co.uk/routers/monitor_linestats.htm

Re: DLM reset request (ADSL2+)

Mardler — Fri, 11 Oct 2024 14:30:17 GMT

About 90 minutes ago I reset the router.

Target SNRM was 4 as it has been for the last 2 or 3 years with excellent sync and a stable connection up for months apart from occasions like this.

The data is as follows with Wednesday first (as indicative of what we have had for years with the Billion router) and today's figures in brackets:-

Actual SNRM: 6.4 (7.1)

Attenuation: 16 (17.5)

Attainable rate: 21220 (14640)

Sync: 20379 (13123)

The degradation is obvious.

Of particular note is the increase in attenuation. This is external and indicates an exchange or line fault as before.

NB. Before I reconnected the connection had been up for 17hrs (with a poor sync of 11179 admittedly) without a disconnect.

Thanks for your input, guys. Here are my responses:-

Mr_P: the distance to the exchange is measurable by following the telegraph poles in the car; the figure was also given to me by Openreach years ago.

Wow: interesting thought however I am fairly sure no-one here uses such devices. The effect of the solar radiation, or lack of it, should be observable tonight.

Years ago we suffered from out of spec low voltage which damaged equipment. Eventually a new transformer was installed a few feet from the house which gives c.235V.

Yup, recent solar radiation might be a culprit, it was a strong one (also a CME last Thursday).

Baldrick: I have done this. Sync dropped to c.9.5mbps. Please note that the tweaked SNR (from 6db to 4) has been used for years with excellent results including a near bomb proof connection apart from these occasional bouts. At one point I dropped it to 2 still with a 100% stable connection. I draw your attention to the attenuation.

Having had several bouts of similar behaviour over the years I am familiar with BT/Openreach requirements.

Thanks for the link. I think it runs on a computer not a tablet so whether a clunky old Windows laptop will run it who knows.

Finally, we can live with download speeds of 13123 (wi-fi 11.2mbps) though the near 20 we had become used to was noticeably better in practice. The frequent disconnects are another matter entirely.

Re: DLM reset request (ADSL2+)

Mardler — Fri, 11 Oct 2024 15:05:24 GMT

Attainable rate now falling.

Tried setting SNRM back to standard (6db) and sync was 11539.

SNRM 4 (6-2) was 12779 (13123 earlier as above).

SNRM 3 (6-3) was 13651.

Attainable rate is nowhere near Wednesday's 21220 (SNRM set to 4 giving an actual 6.4).

Something is definitely wrong.