Loss of ADSL Performance After Joining Plusnet

[#1]

Hi all,

I'm recently new to Plusnet and am looking for some advice re an issue associated with this migration.

My home location is semi-rural, and I'm ~1km from the cabinette I'm connected to, so my broadband speeds have never been great. In the last 5 years I've stuck with "standard" (ADSL2+) as it offers a more stable service ot typically ~10Mb/s. (I did try 1 year of "fast fibre" (VDSL) which although a little faster (~15Mb/s), would frequently drop out and take ages to resync. Definatley NOT compatible with regular home working!).

I have used 3 different ADSL providers here; Post Office (piggybacking off TalkTalk), Shell Energy, John Lewis (piggybacking off Plusnet!). All 3 ISPS achieved stable and near identical download performance of ~10Mbs with ~3dB SNR margin.

About 6 weeks ago I switched to standard (ADSL2+) Plusnet broadband with their supplied HubOne router. After a few days the line had settled down, as I'd hoped, to the download performance as mentioned above. Then about 3 weeks in, there was an event late one evening where I could no longer gain access to the internet for a while (despite the router seemingly remaing in sync and flagging no problems). The following morning, intenet access had been restored but I was frustrated to soon realise that the download SNR margin had increased to ~6dB and my speed reduced to ~7.5Mbs.

I spoke to Tech Supp at length but they were insistant that as the service met their "estimated 1.5-5.0Mbs" then there was nothing they needed to do.

After much discussion I eventually managed to get a verbal agreement that they would reset my IP profile, but I saw no evidence that the router ever re-synced/trained afterwards and the performance remains as was, over 1 week later, as I write.

This is truly frustrating, especially on an already slow connection, especially when I know that the John Lewis (aka Plusnet!) service was perfectly capable of what I'm asking for.

Can anyone please advise what I can do to escalate/resolve this matter?

Thanks in advance (and apologies for the long rant),

Loo

[#2]

For Community members to be able to help, information from these two sites, as screenshots, posted as pictures within the topic, not as attachments:-

BT Broadband(obscuring your phone number) and BTW Performance Tester - Over a wired (Ethernet) connection if at all possible, please report the 'ADDITIONAL DIAGNOSTICS', and sight of the broadband connection status from your Hub (with the 'Username' obscured) would be a good starting point.

For the Hub One -

Navigate from the Home Screen to Troubleshooting > Helpdesk

For the Hub Two -

Navigate from the Home Screen to Advanced Settings > Technical Log > Information

It may also be a good idea to report the results of a Quiet Line Test - dial 17070 option 2 from a (preferably corded) phone. After the confirmation of your phone number, there should be total silence apart from the regular 'Quiet Line Test' announcement. Any other noise - report a PHONE fault first.

If you are unsure about any of the above, please just ask - I am happy to help.

[#3]

Hi @jab1 

And thanks for replying. Here are the screenshots you suggested...

BT BB Checker - Top of ScreenshotBT BB Checker - Bottom of ScreenshotBTW ResultsHubOne Helpdesk

[#4]

Taking those shots in order: The 'observed speed' suggests that you are getting about 9.6Mb/s to your master socket, so your actual speed in the speedtest results is not unreasonable.

Given your attenuation, a 3dB noise margin target is not a good idea - it won't take much to disrupt your connection with so little headroom. You also appear to have only had a 2 day xDSL connection - have you caused this, or is it a failure of the Openreach network?

[#5]

Sounds like there was a burst of errors a couple of days ago, this caused the target SNR to be put back to 6db and thus a resycnh at a reduced speed. Assuming the line stays error free , then eventually the target SNR should/may go back to 3db.

[#6]

@jab1 

Agreed that the observed speed says ~9.6Mbs, but of course this is after the fact of the system training to what it thinks is an acceptable connection status. It has been stably higher before (even JLewis/Plusnet before I switched), I can assure you.

Your statement re 3dB headroom is compelling... but the modern encoding techniques used in xDSL can actually make (some) use of data bins down to near 0dB. Also I have tended to find that if my line is working properly then it doesnt tend to change a lot, despite its length - I've only seen line instability when there's been a confirmed fault in the past (which inevitably BTO ended up fixing).

Not sure why you say it looks like I've been connected only 2 days? I was actually switched to Plusnet @22 Aug i.e. ~5wks ago.

[#7]

Not sure why you say it looks like I've been connected only 2 days?

Because the router stats say :- DSL Uptime 2 days 01:06:30

[#8]

---

@loomajoo wrote:

@jab1 

Not sure why you say it looks like I've been connected only 2 days? I was actually switched to Plusnet @22 Aug i.e. ~5wks ago.

---

You may have switched to PN on 22/8, but as @MisterW says, you had a burst of noise 2 days ago which caused a resync.

[#9]

@MisterW 

Thanks for your input.

The router did resync 2 days ago, but I wasnt around to determine why. Certainly the subsequent connection status looked pretty much unchanged to me when I checked.

Re the SNR margin - I've had a good read thru this forum and elsewhere, and there does seem to be some historical suggestion that Plusnet do target 6dB as a minimum. Do you have any knowldege of this? And how long would I have to wait, do you think, for a possible return to 3dB?

[#10]

@loomajoo 

Re the SNR margin - I've had a good read thru this forum and elsewhere, and there does seem to be some historical suggestion that Plusnet do target 6dB as a minimum. Do you have any knowldege of this? And how long would I have to wait, do you think, for a possible return to 3dB?

All BTw connections will have a default target SNR of 6db. If the line is relatively error free, then the DSLAM will reduce the target to 3db. How long that takes, is basically 'how long is a piece of string' . IIRC it depends primarily on the MTBE (mean time between errors but I'm afraid I've long since forgotten how exactly the ADSL2 DSLAM works.

[#11]

@MisterW 

 Interesting insight - thank you.

On an aside, in between these posts, I did a quiet line test (17070 opt 2). My hearing is not as good these days but the line sounded as usual to me - a low-level/background, mains-like, hum and a very faint hint of background crackle.

However, upon test completion/phone hangup the HubOne did another re-sync... And its stabilised slightly faster than before (~8Mbs vs ~7.5Mbs) altho still ~6db SNR.

Is it normal that the quiet line test affects modem sync?

Can I read anything into the increased download speed, at all?

I know its a small increase, but it all counts when you dont have much to start with!

[#12]

@loomajoo That suggests there is an issue with your voice circuit - using the phone should have no effect on the BB signal.

[#13]

My hearing is not as good these days but the line sounded as usual to me - a low-level/background, mains-like, hum and a very faint hint of background crackle.

@loomajoo the line should be silent. Any noise at all is indicative of a line fault. That conclusion added to by the line resynching when the phone goes on-hook.

Just to elimate any possible internal fault, I'd try replacing the DSL filter OR if you have an NTE5 with a MK4 faceplate, then remove and refit the faceplate, the connectors on the Mk4 are poor and can give problems. If neither of those improves the QLT then I'd report a phone fault using the bot https://www.plus.net/help/report-a-problem/phone/ which should do an automated line test

[#14]

@jab1 

OK... But if there is an issue with the voice circuit, then its something I have not obviously noticed yet... Unless it was behind the mysterious cannot-connect-to-internet event...

Worse still, it may be intermittent, as PN CS said their line check was OK when I reported the shift in Speed & SNR in the firstb place.

☹️

[#15]

Using/testing the phone can sometimes clear it temporarily.