Line Banding

[#1]

Openreach man came yesterday. He didn't seem that well informed about reason for visit or who was responsible for call out (this is always the problem where multiple organisations are involved - but that's politics!). He seemed familiar with broadband but unfamiliar with the term "Banded" which I was relying on (too much?) to explain the issue. I should have boned up on the matter beforehand, as it was the discussion got bogged down over the simplistic issue of "speed".

His general view aligned with my opinion that, with the growth of BB, there was just so much cross-talk etc. that things were not going to be as they once were. Fibre to the premises being the only real answer.

His overall opinion: The line is working OK, you are getting nearly 15 Mbps, the current maximum forecast for the line is 15 Mbps. So as far as Openreach are concerned there isn't an issue. He did suggest I could look into getting Interleave removed.

My own experience locally over the years is of ongoing general deterioration in the entire RF broadcast spectrum - everything from AM Medium Wave to DTV on Band IV/V.

Should we then all simply get used to ADSL 2+ continuing to degrade over the years until FTTP arrives?

My ADSL was up continuously for 27 days, it did reconnect for some reason a day or so before the engineers visit (OR testing?) and obviously again on Friday. Currently errors on the line are mainly noticeable by their absence, but it remains banded at 888/14,335 (the max for that band, WBC 7M - 14M) with SNRM of 16.1dB/7.4 dB

PS. The errors have gone up again - just noticed, looking at the Bitloading map, that RF signal has reappeared - 3.15p Saturday afternoon.

Trouble is, DSLstats seems buggy wrt reporting Tones/Frequencies. The DSLstats plot scale Tone number and DSLstats reported Tone numbers don't even match on Custom and ADSL 2+ settings, only on ADSL(2) and VDSL2! So I get different results for the frequency depending on whether I use Custom (my usual), ADSL 2+ or ADSL(2) Tone Range settings:

Custom: 344, 1483.5 kHz
ADSL2+: 447, 1927.6875 kHz
ADSL (2): 386, 1664.625 kHz
VDSL2: 385, 1660.3125 kHz

So, going with the ADSL (2) and VDSL2 results, I guess Tone number 386, 1664.625 kHz is the best estimate. Outside the range of my AM receiver. Anyone have a short wave receiver handy?

The trouble is, this frequency isn't covered by Internet SW information sites as it is classed as MW. And officially broadcast MW ends just over 1600 kHz.

http://mediumwave.de/

"1610 - 1700 pirate stations from the Netherlands
1610 - 1800 pirate stations from Greece and the Balcan (some also operate in the regular MW range)
(powers reach from Milliwatts up to 25 KW. A Greek radio amateur told me that there are at least 10 stations with more than 5 kW)"

I still cannot be certain this rogue signal is or is not the cause of the problems.

[#2]

Looking at the line @pvmb, it has stabilised since the visit and the speed is within the estimates provided in your contractual email.

It is still showing errors on the upstream, are you still using the original router we sent you?

[#3]

I see no evidence that it has since "stabilised", it is performing identically as before. Welded to the very top speed allowed in the WBC 7M - 14M banding (7168 kbps to 14336 kbps) with seemingly very low errors.

Up speed: 888 kbps, Up SNRM: 15.2
Down speed: 14335 kbps, Down SNRM: 7.4 dB

So why isn't it simply in the default ADSL 2+ WBC 160k - 24M, Unbanded (up to 24576kbps) - whatever the actual speed attained?

Or do we now simply have to accept that the general UK situation wrt ADSL is such that on a pretty average phone line with no obvious problem and entirely normal loop losses, the previous default, normal ADSL 2+ service (which once upon a time supplied me with a stable 18Mbps) can no longer be expected to be available, only a banded and restricted version?

[#4]

Thanks for getting back to me @pvmb, I appreciate it.

When a contract is taken as a provider we will always provide an estimate speed range for your line and should it drop below this speed, we will work hard with our suppliers to resolve this.

I can see that we advised that we quoted your estimates speeds of 4Mbps to 14Mbps shown here. 

It is great that your speed was higher previously and your line achieved this, but as it is current in line with what we expected for your line and with what our supplier quoted it can handler, there isn't anything we can do to increase it.

I have checked your connection and as you can see from the image below, it had dropped for a number of hours. I'd like to check if this was due to anyone tuning the router off during that time?

[#5]

@SammyM  Your response to @pvmb is unhelpful and to be honest disappointing. You have not answered the question of why the line is banded, but instead taken the easy way out by saying the line is within speed estimates, which are somewhat  arbitrary figures. My own speed estimates on fibre extra are 64-72 Mbps and I expect to get speeds well above that as I have a full 80Mbps sync speed. As these speeds are estimates it is perfectly reasonable to expect higher actual speeds.

So as pvmb says why isn't the line on the full ADSL2+ profile WBC 160k - 24M, unless there are line faults there should be no reason for the line to be banded?

[#6]

@SammyM wrote:

Thanks for getting back to me @pvmb, I appreciate it.

When a contract is taken as a provider we will always provide an estimate speed range for your line and should it drop below this speed, we will work hard with our suppliers to resolve this.

I can see that we advised that we quoted your estimates speeds of 4Mbps to 14Mbps shown here. 

It is great that your speed was higher previously and your line achieved this, but as it is current in line with what we expected for your line and with what our supplier quoted it can handler, there isn't anything we can do to increase it.

Yes, but WHY is my line speed 14Mbps? (It wasn't until quite recently). Currently there is a very simple answer to that question: Because it isn't ALLOWED to be any higher - as it is banded to restrict the speed to a maximum of 14336 kbps. Which is exactly the speed I am getting, every time.

If I was on unrestricted ADSL 2+ and my line not faulty it would be quite possible for me to end up with a maximum speed of say less than 8 kbps. This would be entirely acceptable and understandable, if my line length was over 3 km and the line loss 45dB. From the Kitz.co calculator: 45dB, 3.3 km, 7200 kbps

https://kitz.co.uk/adsl/max_speed_calc.php

But, as it is, my line loss is 28db, and from the Kitz.co calculator this represents a 2 km line length and I could expect something like 16512 kbps. Which is indeed near what I was, until recently, getting!

It isn't a simple question of what speed I think I 'ought' to be getting, rather it is a simple(or not?) question of why is my line speed currently restricted to a maximum figure. Seemingly not restricted by line length, but by banding to WBC 7M - 14M. This appeared not to be the case until quite recently.

From the account details mentioned:

Broadband product:Unlimited (Contracted)

Estimated speed: 4Mbps to 14Mbps
This estimate is based on data provided by our supplier. Your actual speed will vary but should be within the estimated range.

Yes. This is true NOW (since recently) because it is now RESTRICTED to be in this speed range.

Find out why your speed can vary - https://www.plus.net/help/broadband/broadband-speed-estimates/

The above link doesn't provide such information.

Whatever the facts, it does rather look to me like the speed is now being restricted to fit the "estimated speed" range.

And the Openreach "estimate" is/was 15 Mbps.

@SammyM wrote:

I have checked your connection and as you can see from the image below, it had dropped for a number of hours. I'd like to check if this was due to anyone tuning the router off during that time?

I have turned the router off a number of times in order to test things. It always reconnects at the exact same speed: 14335 kbps, 888 kbps.

[#7]

I think there's a level of expectation that needs to be set. 

I agree, it is odd that your speed is continually banded at 14mbps, despite our efforts to remove it. 

Due to a combination of line tests aren't showing the cause for this, we've sent out an Openreach engineer to take a closer look, you don't seem to be having any other issues, and your speeds are within our suppliers current expectations for your line, I think we've done as much as can do to try to get to the bottom of this. 

There really isn't another way for us to investigate further, apart from sending out another engineer.

The speed estimates for your line may have been higher previously, but as the infrastructure is dynamic and ever-changing, the estimates can be revised and these can be checked at: https://www.broadbandchecker.btwholesale.com/ (Currently, they're showing to be between 7.5mbps to 12mbps).

I've again removed the banding for you though which should take effect within 10 minutes. I've also increased the speed profile on your account to the max of 21mbps to make sure that we're not being the bottleneck. 

[#8]

Thanks.

Yes, speed stepped at 20:24 to: 15993 kbps, 6.2 dB; 888 kbps 15.5 dB

CRC & FEC errors peaked at switchover time, but since seem OK. Though now may have higher Bitswaps per Tone.

Will see how it goes...

[#9]

"I fought the law and the law won!"

Nope, this line is just not going to be allowed to operate outside the current official ADSL estimated 14Mbps range, despite it seeming physically able to do so.

I had one accidental disconnection - caused by my inadvertently turning off the power - and worried it might reconnect at a lower rate. It didn't, it reconnected at ~16 Mbps and continued operating just fine. I left it on overnight. But then...

Sometime, early in the (quiet?) Friday morning, I reckon about 5:24am, something happened (just like last time). I assume a drop and reconnect, I don't know because the computer was off and so no monitoring was going on there.

And of course it was now back to 14 Mbps - just like last time!

[#10]

I have decided to revert to a policy of turning my router off every night and on again in the morning when needed. My thinking being:

1. It does no harm (see below)

2. It minimises your ADSL line's time exposure to 'events'

It's clear, from my past experience of doing this, that it does no harm to your ADSL speed (despite it often being advised against!). Further, here is the explanation from Kitz why this is so:

https://kitz.co.uk/adsl/DLM.htm#dlm_sync_events

~ Detection of sync events

"The DLM only counts 'forced' retrains and will disregard any resyncs detected as being an Unforced Retrain or one caused by a Wide Area Event."

https://kitz.co.uk/adsl/DLM.htm#unforced_retrains

2. Check for Unforced Retrains
"An unforced retrain is one in which the user switches off or unplugs their modem for "a period of time greater than the minimum period of time" and that a minimum period of time prior to or after a resynchronisation has elapsed without the line automatically attempting, but failing to establish a connection."

[#11]

ADSL Curiosity

I am not asking for any action to be taken, this is just a simple request for information to try and satisfy my curiosity.

Can someone please confirm the current status of my Broadband line. To me it appears to be permanently banded WBC 7M - 14M and to be permanently working at the highest download speed allowed in that band.

I can add a couple of things, a previously suspected ~1.6MHz signal(?) on my line seems to have passed on. Currently the line is immensely stable, sometimes with zero average error seconds over extended operating periods - with exactly the same speed parameters every time the router is switched on. And yes, I have reverted to a policy (when I remember!) of turning the router off at night, or when not needed, and turning it on when needed.

I have now accepted this new(?) way of operating (as long as there are no more significant downward moves) but do wonder if it does reflect some relatively recent change in managing ADSL BB by Openreach (updated DLM software?). It seems different to how things used to be (unbanded, standard 6dB SNRM, varying connect speeds).

Any answers?

TIA

[#12]

Good morning @pvmb, thanks a lot for getting back to us. Testing the line this morning has found the circuit to be out of sync at the moment. I could be wrong, but I suspect you've got it turned off. 

While it's unclear as to why your line keeps getting banded at 14Mbpos, be advised that your estimated are in fact between 4-14Mbps, and that turning your router on and off is likely to have an adverse effect on your connection. Give me a nudge when you're online and I'll run some tests and pop some stats on here.  

[#13]

adam, Yes my line would have been off earlier on. As I previously posted I have reverted to turning the router off when not needed and on when needed. (If nothing else this now saves a little bit of leccy!)

I am certain this will NOT have an adverse effect on my connection. This is based on two things:

1. My current experience and all prior experience of doing just this.
(e.g. originally, when I used to turn my router off every night and on again in the morning, it never prevented me getting a steady ~18Mbps download every day. It was physical faults - router and line - that stopped that)

2. Technical information from Kitz.co.uk, on BB and operation of the DLM, confirms my experience.
(I have already given links to this source in a previous post above)

The thing is I'm not asking for my line to be tested - AFAIAC there is currently no physical fault on the line - just asking for confirmation that it is banded, nothing more.

Looking around this site I seem to be seeing increasing numbers of posts that, to me, sound as if people are having the same 'issue' as myself - even on Fibre.

I have put forward an idea of what might be going on - a policy of enforced banding (on an exchange basis) to keep lines within specified limits as advertised, even if a particular individual line may be capable of higher speed.

Now I cannot be 100% sure my notion is correct and Plusnet support seem to be denying it. However, if it were a new policy it would presumably not be a Plusnet policy, rather a BT/Openreach policy which Plusnet support might not even be aware of.

The thing is, if it is a new BT/Openreach policy, it would be best for both Plusnet support and Plusnet users to know about it and understand it. Otherwise both could spent a lot of time chasing non existing 'faults' on lines.

[#14]

If it works for you @pvmb, who am I to say stop doing it?

As far as I know though, it can sometimes lead DLM to thinking that the line is unstable, and therefore bands it in order to preserve stability. In terms of seeing what profile your connection is on, I'm only able to do so when I run a KBD test on the line, hence my attempt earlier. 

I've just tested the line now, and can confirm that you are on a banded profile: WBC 7M - 14M Low delay (INP 0) 6dB Downstream, UC Medium delay (INP 2) 6dB Upstream (ADSL2+)

I'll pop my KBD results below, showing that your download sync speed is just over 14Mbps. Downstream SNR is slightly higher than the target value, indicating a slight stability issue, likely offset by DLM banding the line, but that can't be said for certain at the moment. 

Going forward, I'd be more than happy to un-band the line and turn DLM OFF, meaning it'll no longer intervene, do you want to go ahead with that and see how things go? It's a reversible change so if things go south, we'll turn it back on. 

KBD

xDSL Status Check
Circuit ID:		Service ID:
Telephone NO.:	NA	Test Executed On:	18-04-2022 17:01:27

xDSL Status Test Summary
Sync Status:		Circuit In Sync
General Information
NTE Status:		NTE Power Status:	PowerOn	Bypass Status:

	Upstream DSL Link Information	Downstream DSL Link Information
Loop Loss:	14.8	29.0
SNR Margin:	15.0	7.3
Errored Seconds:	0	0
HEC Errors:	0
Cell Count:	1802	5406
Speed:	888	14335

Maximum Stable Rate (KBPS):	15904	Fault Threshold Rate (KBPS):	12723
Mean Time Between Retrains (Seconds):	86400	Mean Time Between Errors Upstream (Seconds):	86400
Indicative Line Quality:	A	Mean Time Between Errors Downstream (Seconds):	3962
Custom Thresholds
MTBR_RED:	MTBE_RED:
MTBR_GREEN:	MTBE_GREEN:

Your policy of enforced banding theory is wrong, particularly from a DLM profile perspective. We have plenty of customers on ADSL and FTTC who actually exceed their speed estimates that were initially advertised. Some customer do find themselves banded on our internal connection profile - those connected via L2TP, though this is usually reset at the earliest opportunity when we're made aware of it, you'll find plenty of threads on here where we've done this. 

Let me know your thoughts on turning DLM off.  

[#15]

---

@pvmb wrote:

adam, Yes my line would have been off earlier on. As I previously posted I have reverted to turning the router off when not needed and on when needed. (If nothing else this now saves a little bit of leccy!)

I am certain this will NOT have an adverse effect on my connection. This is based on two things:

1. My current experience and all prior experience of doing just this.
(e.g. originally, when I used to turn my router off every night and on again in the morning, it never prevented me getting a steady ~18Mbps download every day. It was physical faults - router and line - that stopped that)

2. Technical information from Kitz.co.uk, on BB and operation of the DLM, confirms my experience.
(I have already given links to this source in a previous post above)

---

So how's it working out? Just fine. 🙂

Apart from my bad memory meaning I not infrequently forget to turn it off at night then, in the morning, I turn it 'ON' and realise I have just turned it 'OFF' instead, leading me to immediately turn it 'ON' again. 🙄

But this just makes the point, as it still works flawlessly every time at exactly the same rate.

So I seem, finally, to have adapted to the 'New Regime'(?). The speed is not the max that I may feel the line can support, but it is only slightly slower and more than adequate for my needs. But the stability is something else - it never budges and the error rate is generally almost vanishingly low.

I still feel/think the speed banding could be a manifestation of a new way of managing ADSL (due to a changed environment?) and that some documents/opinions about ADSL are now possibly out-of-date and misleading. I could be wrong.

However...