Broadband issues - need to contact support to update ticket

[#1]

Mid-November my broadband kept dropping out every few minutes.  I did the TEXT broadband tester which reported no issues so I spoke to an advisor.  They said they couldn't help becuase I didn't have a Plusnet router but they could send me a Plusnet router (hub2).  This arrived but in the meantime, my broadband connection stabalised but the speed dropped from 39Mb to 19Mb (download).  Upload is still okay at 9Mb (I am on a 40/10 contract).

I can't use the Plusnet router for my setup because it doesn't have enough SSIDs or VLANs etc. However, I can set it up temporarily for a day or two so Plusnet are able to do some proper testing.

I want to schedule this for this Friday afternoon to Sunday morning. Plusnet opened a ticket 238317837 for the incident but I can't find a way to update the ticket or contact support to let them know what I am going to do this weekend and to arrange for them to run the tests.

Hopefully there is someone from Plusnet support here who can get in touch.

[#2]

@cjags Do you really need to use the Plusnet router, I've been with Plusnet for years and never had one. I've certainly raised speed faults on a few occasions, mostly due to Openreach cable problems. If support tell you they can't help because you don't use a Plusnet router say that is not true, there is no obligation to use their router.

If your speed has dropped to 19Mbps that's a speed fault whatever router you are using so raise another fault, I expect your earlier ticket has closed so you can't update it. I think you may find it difficult to arrange for Plusnet to do tests over a specific time period

[#3]

Plusnet support said they needed a Plusnet router to perform thier tests.

I don't need one for day to day use but I can (now) hook one up for them to do tests if that is what they want to do.

[#4]

It is certainly the case that Plusnet routers facilitate "richer" diagnostics than third party routers, especially when looking at WiFi caused issues.

The first pass here should be to do the basics...

1. Are you FTTC (as opposed to SOGEA)?  If yes, please perform a quite line test - dial 17070 option 2 - possibly the most expedient way to test a line
2. Post the router line stats - specifically SNRM and line speed

If there is noise on the line, the raise a TELEPHONE line fault report.

We can look at the router stats data and then suggest questions to ask of support.

Speed tests - which one and in what configuration - over direct ethernet (wifi turned off) or over WiFi?

[#5]

Yes it is FTTC.

Quiet line test isn't totally quiet. There is a click every 3 or 4 seconds.

Router line stats

Line 1 Information      (VDSL2Firmware Version:  8D1B17_A/B/C   with Vectoring support )

Profile	State	UP Speed	Down Speed	SNR Upstream	SNR Downstream
17A	SHOWTIME	9,998 (Kbps)	17,987 (Kbps)	9 (dB)	16 (dB)

[#6]

Doing the Phone Bot tests...

[#7]

@cjags From the line stats it would appear that your sync rate is banded ( i.e capped) at around 18Mbps. This would explain the extremely high SNR value of 16db, it should be 6dB or possibly lower.  The upstream speed is normal at full 10Mbps.

Phone support and ask for a DLM reset, your downstream speed should be much higher.

The automated tests are not very intelligent and will probably say nothing's wrong.☹️

[#8]

There will be a reason that the DLM is managing the line aggressively ... so there is little point doing a reset without examining why the SNRM is 16dB.

The line clicks do not sound healthy - this should be reported as a noisy line fault in the first instance.  Are you rural?  I have seen suggestions that this phenomenon can be caused by farmer's electrical fences ... in conjunction with other line issues.

[#9]

Not really rural. In a town on edge of New Forest, but we do have Virgin digging up the pavements to lay fibre and it has been raining a lot so everything is pretty wet.

PHONE Bot has finished and says nothing found BT side and has suggested some checks for me to do on the home side.

Trouble is, I don't have a POTS anymore so can only test with a wireless handset.

I do have more than one set, so I can test with different equipment to see if the clicks on the line persist.

[#10]

The automatic tests do not detect all faults.  Might be worth calling support and report the audible clicks.

[#11]

I will test again with the broadband disconnected and use different phones to rule out local equipment issues. If the clicks perist, I can talk to an advisor using the bot.

[#12]

@Townman  Surely the reason why the SNRM is high is because DLM has capped the sync speed. Why it has done that is the question. A DLM reset will not do any harm, should increase the speed at least temporarily, if the line is unstable DLM will act again.

[#13]

The question needs to be why has the speed been capped? Speeds get capped to avoid sync drops. I would suspect that the reported clicks are responsible for a history of disconnections.

Increasing the SNRM (lowering the speed) allows the sync to survive those clicks. A DLM reset initiates a new 10 training period … which if unsuccessful leaves the OP with very iffy broadband through Christmas.

Doing a DLM reset without knowing that what caused the capping has been fixed … is a bit like blowing up a tyre … which has a slow puncture. A day or so later, it’s flat again.

[#14]

@Townman I think you are a bit confused about how DLM works, it does not reduce the speed by increasing the SNRM but, the other way round by setting the sync rate to a banded value so the effect is to increase the SNRM so making the line more stable.  Also it is widely known that there is no 10 day training period on FTTC, DLM is running continuously, adjusting the speed as required if the line is dropping the connection.

It is not yet been confirmed that the clicks on the phone line are causing disconnections.

[#15]

And it’s not been proved they are not the cause. Something is not right.

Speed down SNRM up is semantics - SNRM is usually stepped in 3dB. It’s complicated, but the result is the same, the line runs slower so there’s a bigger signal over noise margin.

Though in the case of VDSL2 there is no 10 period … I doubt the ISP will act further until 10 days after a reset.