Stable Line Gone Bad

[#1]

Hi,

I've been a happy plusnet customer for about 14 months with what has been a rock solid ADSL2+ connection throughout most of that time with an upstream sync circa 1000, and downstream circa 14000. Problems started about 10-14 days ago with frequent resyncs and some wild variations in noisemargins. DLM kicked in last week acting to increase the upstream SNR, reducing the upstream sync - I think the lowest was below 400. Line seemed to stabilise over the weekend and DLM seems to have lifted and I'm back up to old connection rates but ES are still high and resyncs are frequent particularly over night. I think wet weather may also be a factor. I've checked my internals and everything is OK, not gone as far as changing microfilter or router as it stands. Any suggestions.

[#2]

Changing filter and plugging directly into the test socket (if present) is always a good first step to take, if only because you will have to do that anyway if you need to raise a fault ticket.

If you have a spare router you can then try that from the test socket too to see if it makes any difference.

Other thing to check for is any noise on your telephone line (dial 17070, select option 2, using a corded phone.)

[#3]

Your line is dropping a lot:

Testing your line is showing the SNR margin is very low and the mean time between errors is only at 21 seconds.

	Upstream DSL Link Information	Downstream DSL Link Information
Loop Loss:	13.3	28.0
SNR Margin:	6.5	2.3
Errored Seconds:	0	28
HEC Errors:	0
Cell Count:	99346804	6099717
Speed:	1099	14804

Maximum Stable Rate (KBPS):	13632	Fault Threshold Rate (KBPS):	10906
Mean Time Between Retrains (Seconds):	5207	Mean Time Between Errors Upstream (Seconds):	1176
Indicative Line Quality:	R	Mean Time Between Errors Downstream (Seconds):	21

We can increase the SNR margin to try and alleviate those errors, which may help to stablise the line, this will sacrifice a little speed though.

[#4]

Thanks Chris,

The connection graph isn't pretty is it?

Hold off on tweaking the line for the time being - historically those SNR margins have been OK. Connection continued to drop regularly throughout yesterday and overnight but I've just tried resetting the router via a simple download and upload of it's config file and on reconnection it seems a little bit more stable.

If the line remains unstable I might try a full factory reset of the router and set it up again from scratch and see if that helps

If that doesn't work I'll ask for the SNR margin to be raised and may try and source an alternative router. Current router is an old talktalk HG533 which has served me well but is about 6 years old now.  I can't find the plusnet supplied router and the only other one I've got to hand is an old talktalk DSL 2780.

Thanks,

[#5]

I've not made any changes at the moment and will wait till we hear from you about this again. Let me know how it goes.

[#6]

Thanks Chris,

Found the so far unused plusnet supplied 2704n router buried in the bottom of a wardrobe and switched over to that yesterday but still suffering instability.

Please do look to raise the target SNR.

Can you also look into the possibility of a line/exchange fault?

I don't understand why DLM hasn't kicked in at all this week given the error and reconnect rates on the line and the old router has been connecting  at slightly higher sync rates than I have seen when the line was stable.

The 2704n is also syncing at a surprisingly high downstream rate although the upstream is not as high as the previous router.

[#7]

Haven't been home much over the weekend to monitor the line but is has definitely had some reconnections. Also like last weekend DLM (or something) has kicked in but is only limiting the upstream sync speed. Syncing at about 444 with a SNR of 13dB. Downstream is still syncing at circa 17000 with an SNR of 1-3dB with high ES rates.

Does the 2704n have any user accessible QOS settings? Seems very prone to a saturated upstream causing other devices or services on the same device to report no internet access. My old talktalk HG533 managed a saturated upstream much better...

[#8]

The line is looking a lot more stable since around 7:15pm last night:

The line stats (with the exception of the upstream) are looking a lot healthier now too.

	Upstream DSL Link Information	Downstream DSL Link Information
Loop Loss:	13.1	26.5
SNR Margin:	12.0	1.8
Errored Seconds:	0	0
HEC Errors:	0
Cell Count:	27423313	1545851
Speed:	444	17162

Maximum Stable Rate (KBPS):	13632	Fault Threshold Rate (KBPS):	10906
Mean Time Between Retrains (Seconds):	15443	Mean Time Between Errors Upstream (Seconds):	6864
Indicative Line Quality:	A	Mean Time Between Errors Downstream (Seconds):	643

The loop loss is lower, there are no errored seconds and the mean time between errors has increased.

I'll go place the order to uncap the upload again, this should complete overnight and we'll take a look at the stats tomorrow and see if we need to increase the downstream SNR then if that's ok.

[#9]

Thanks Chris,

Much appreciated. Line seems to have stayed stable throughout the evening and overnight. The upstream cap still seems to be in place - just rebooted the router at 6am this morning and it's still syncing at 444.