topic Re: Declining ADSL Speed in Broadband

Declining ADSL Speed

pvmb — Fri, 10 Dec 2021 19:13:36 GMT

What's happening now with my ADSL? It feels as if it is being throttled for some unknown reason. Long ago now I accepted my original 18,000 kbps SNRM 3 dB line had gone for good (Why?) and grew used to my 'new' 6 dB 15,000 kbps line. But now I cannot even get that! Although there seems no indication of any fault or even serious error rates I seem stuck on less that 15,000 kbps as, whenever I reconnect my Down SNRM now heads to ~8 dB.

Why should this be happening?

(I do notice a rather large 'hole' at about 1483 kHz/Tone 384 in the bitloading plot)

Up speed: 1231 kbps - Up SNRM: 6.3 dB - Interleave (Down/Up): 1/0
Down speed: 14335 kbps - Down SNRM: 7.6 dB - ES/hour (Down/Up): 32.1/0

Re: Declining ADSL Speed

pvmb — Fri, 10 Dec 2021 19:32:16 GMT

That 'hole' has partially backfilled now. I also notice bit swaps centred mainly around the same frequency range. Reading Kitz on "Bit Swaps" suggests they are caused by noise bursts on particular tones. So is this the answer?

As I sometimes see periods of no bit swaps perhaps I should reboot my router then?

Re: Declining ADSL Speed

Anywho — Sat, 11 Dec 2021 00:19:54 GMT

I'm no expert... but I would say that if SNRM was 6 when you last retrained then the best thing to do would probably be to retrain next time that peaks (like now!)…it will negotiate back to 6 and you will get the extra sync rate!

Of course, next time the line gets noisy your SNRM will drop and so might your connection.

Is it worth the extra few hundred Kbps when the line is quiet or do you prefer to have the stability (even at noisy times) that the extra margin provides?

Re: Declining ADSL Speed

pvmb — Sat, 11 Dec 2021 15:25:23 GMT

It seemed very quiet today, bitswap wise, so I rebooted.

Down speed: 14335 kbps - Identical!

So it's 14335 kbps or nothing? Currently it's looking like they are the only two options. What's going on? Is this going to be another of those ADSL mysteries - like my fixed IP address?

The SNRM is moving to match a fixed speed - the speed is, currently, just not changing.

Down SNRM started at 7 dB, qickly moved down to 5.5 dB, gradually moving up again (heading back to 8 dB)

Same hole in bitloading spectrum as before - some bitswaps, again in same place...

Re: Declining ADSL Speed

pvmb — Sun, 12 Dec 2021 09:23:16 GMT

Shut down router overnight, rebooted in morning. Do I have to tell you my download speed? No!

14335 kbps - Identical! Curiously, this morning, that hole in Bitloading map has gone.

So, currently my ADSL 2+ download speed is pegged to an absolute and fixed speed that cannot be renegotiated. Why?

Re: Declining ADSL Speed

Anywho — Sun, 12 Dec 2021 12:23:18 GMT

Curiously, Kitz says there is a banded profile very close to that number (Kitz ).

Re: Declining ADSL Speed

RealAleMadrid — Sun, 12 Dec 2021 14:03:31 GMT

@pvmb It is almost certainly banded at that speed, if you sync at the same speed after a resync. Plusnet can remove the banding.

Re: Declining ADSL Speed

pvmb — Sun, 12 Dec 2021 20:04:40 GMT

@Anywho wrote:

Curiously, Kitz says there is a banded profile very close to that number (Kitz ).

Yes, 14336.

Kitz says banding is applied to lines that have difficulty maintaining sync at a higher speed. But I wasn't having difficulty at 6 dB, so I will ask if the banding can be removed. Plusnet!

Thanks.

Re: Declining ADSL Speed

pvmb — Sun, 12 Dec 2021 20:22:30 GMT

BT Wholesale Speed Test - On WiFi, but still:

Advance Test

Download Test
Download speed achieved during the test was 1.97 Mbps
For your connection, the acceptable range of speeds is 4 - 21 Mbps
IP Profile for your line is 12.65 Mbps

Upload Test (This never makes sense)
Upload speed achieved during the test was 0 Mbps
IP Profile for your line is 0.83 Mbps

Oops!

Re: Declining ADSL Speed

jab1 — Sun, 12 Dec 2021 20:27:08 GMT

@pvmb Which modem/router are you using? can you post a screen shot of the data page - obscuring personal data, of course.

Sounds like there is something slightly deeper going on.

Re: Declining ADSL Speed

pvmb — Sun, 12 Dec 2021 21:25:18 GMT

Router is Technicolor TG582n, Data from DSLstats:

John, Can't format correctly here - Notepad file attached

Re: Declining ADSL Speed

jab1 — Sun, 12 Dec 2021 21:35:54 GMT

@pvmb Apart from the low uptime I can't see much wrong there, It is a while since I've used a 582N, but don't they have a page that gives all that data and a bit more in a more readable format? I'll have to go looking at my old image uploads to find the one I'm talking about, so I'll be back if I can find it.

Something like this:-

Re: Declining ADSL Speed

pvmb — Sun, 12 Dec 2021 21:44:26 GMT

Only this - as above:

Broadband Connection

DSL Connection

Link Information

Uptime: 0 days, 12:23:06

DSL Type: ITU-T G.992.5

Bandwidth (Up/Down) [kbps/kbps]: 1,231 / 14,335
Data Transferred (Sent/Received) [MB/MB]: 10.89 / 85.51
Output Power (Up/Down) [dBm]: 12.9 / 0.0
Line Attenuation (Up/Down) [dB]: 14.4 / 28.5
SN Margin (Up/Down) [dB]: 6.0 / 7.9

System Vendor ID (Local/Remote): TMMB / ----
Chipset Vendor ID (Local/Remote): BDCM / IFTN

Loss of Framing (Local/Remote): 0 / 0
Loss of Signal (Local/Remote): 0 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): -

Error Seconds (Local/Remote): 442 / 0
FEC Errors (Up/Down): 0 / 0
CRC Errors (Up/Down): 57 / 596
HEC Errors (Up/Down): 131 / 4,009

Re: Declining ADSL Speed

jab1 — Sun, 12 Dec 2021 21:53:10 GMT

Thanks - much easier to read than the DSLstats report.

I haven't read all the topic (sorry), but are you seeing a lot of PPP drops - you presumably had one about 12.1/2 hours back?

A Radius graph (and possibly a KBD report) from PN staff may be useful.

Re: Declining ADSL Speed

Gandalf — Mon, 13 Dec 2021 13:02:28 GMT

Thanks for your post @pvmb

I'm sorry to see you're having speed issues.

I've tested your line today and the tests aren't showing the cause for this, but I can see your line is indeed banded at "WBC 7M - 14M No delay (INP 0) 6dB Downstream, UC No delay (INP 0) 6dB Upstream (ADSL2+)"

I've arranged to remove the banding now, which should go through within the next hour.

With regards to your fixed IP address, I believe I solved that mystery for you Here (you have the broadband firewall on)

Let us know how it goes.

Re: Declining ADSL Speed

pvmb — Mon, 13 Dec 2021 14:02:09 GMT

OK Gandalf, the router has now reconnected at 6 dB SNRM. I will have to try and remember the reason for the fixed IP. 😊

Thanks.

Re: Declining ADSL Speed

pvmb — Tue, 14 Dec 2021 14:17:54 GMT

Oh no, this has reverted! Following a disconnection, for unknown reasons, early this morning:

Dec 14 05:33:47 xDSL linestate down

Down speed: 13775 kbps Down SNRM: 9.1 dB

Still nothing obviously wrong with the line.

Re: Declining ADSL Speed

adam945 — Tue, 14 Dec 2021 17:33:37 GMT

Hello @pvmb

Thanks a lot for reaching out and I'm really sorry to hear that you're having problems with your connection. You're right, everything does seem fine on our end, I'm also seeing downstream speeds of 13.75Mbps.

Can I ask, are you switching off your router at night? This does nothing good to the line, and in fact causes problems with your DLM profile, SNR and therefore your download speed.

If you are, please avoid doing this going forward.:)

Re: Declining ADSL Speed

pvmb — Tue, 14 Dec 2021 23:37:00 GMT

I think this "router off overnight" business is a distraction.

The router speed will not change once it has connected - it requires a disconnection and reconnection to do that - it is shown on your chart as having been on continually for "23 days" at the normal speed.

After that, the overnight reboots were me either testing or trying to get it to sync again at the original 6 dB profile the next morning. I then asked for help here, banding was removed and, following a reconnection it continued as 'normal' at 6 dB download.

Then, following a break in connection on Dec 14 @ 05:33 of unknown origin, this is seen on the chart, it reconnected once again at the lower speed 9 dB SNRM. The same situation as before the problem started. It won't now change speed, whatever happens, unless there is a new reconnection.

Re: Declining ADSL Speed

Gandalf — Wed, 15 Dec 2021 09:45:30 GMT

Thanks for getting back to us @pvmb

I've tested your line and the tests aren't showing any causes for the increase in SNRM and drop in speed. Apologies for the drop you've had just now, and if you were in the middle of anything, that would've been me testing your line.

As your speed's within the estimated speed range for your line of between 7.5mbps to 12mbps, not sure there's much we can do in the way of an investigation as it's unlikely an engineer would be able to investigate further.

Do you know that fibre's available in your area? It may be worth looking at upgrading as you can get 70.5mbps to 80mbps on our fibre extra package, or up to 40mbps on our basic fibre package. It may be worth calling our Customer Options Team on 0800 013 2632 if you're interested as it may not necessarily be (much) more expensive.