Lost about 10mbps

I had a very short power cut a couple of days ago.
And now my TBB speed tests show a lose of about 10mbps.
I am with Daisy Wholesale [SSE] on a 80/20 FTTC package.
The DLM would not react to a five minuet power cut , surely.?

What stats does the modem show ?

DSL Uptime
5 days 22 hours 37 minutes 3 seconds

DSL Type
VDSL2

DSL Mode
Fast

Line Rate
�i 20 Mbps �h 71.71 Mbps

Data Transferred
�i 750.69 MBytes �h 3849.2 MBytes

Output Power
�i 6.8 dBm �h 13.5 dBm

Line Attenuation
�i 6.2, 19.9, 29.4 dB �h 10.5, 23.5, 35.5 dB

Noise Margin
�i 10.2 dB �h 6.4 dB

The modem/router does not show more.

Edited by deleted (Sun 10-Mar-19 23:15:37)

What DLM does depends on the way the power cut happened.

If it went off "bang", like you just pulling the power plug out, no I doubt if it would. But if it flickered on and off a few times, which you might not even notice, with all sorts of electromagnetic noise during all that, then the error counts on the line would have gone through the roof and caused a reaction from it.

That noise could in fact have been occurring for a while before the power actually went off. Same bad effect on DLM.

Edited by RobertoS (Sun 10-Mar-19 23:16:46)

In reply to a post by RobertoS:

What DLM does depends on the way the power cut happened.

If it went off "bang", like you just pulling the power plug out, no I doubt if it would. But if it flickered on and off a few times, which you might not even notice, with all sorts of electromagnetic noise during all that, then the error counts on the line would have gone through the roof and caused a reaction from it.

That noise could in fact have been occurring for a while before the power actually went off. Same bad effect on DLM.

You could say that it was the same as pulling the plug as the house power just went off.

Read my post again. Maybe the edit wasn't there when you started your reply .

In reply to a post by RobertoS:

Read my post again. Maybe the edit wasn't there when you started your reply .

Same reply:
You could say that it was the same as pulling the plug as the house power just went off.

[shrug]
"You can lead a horse to water, but you can't make it drink".

Edited by RobertoS (Sun 10-Mar-19 23:42:18)

In reply to a post by ironman12345:

Noise Margin
�i 10.2 dB �h 6.4 dB

Maybe your line has a 6dB noise margin target but has been slowly going below it (e.g. due to increased crosstalk), and DLM set a 70M cap to restore it to 6dB. The power cut forced a resync at which point it applied this cap.

Hi

It may just be cross talk and the power cut hasn't really caused anything, it's hard to know unless you have a before and after picture of the line.

VDSL has all sorts of tricks it applies to help reduce the impact of cross-talk and so some lines may have some speed sacrificed in order for someone else to get something a bit faster. Other customers may have come on line in the days or weeks before the power cut which caused cross-talk to your line but it was still able work okay at a reduced margin.

So if you've had a power cut in the area then it's likely most or all connections to the cabinet also dropped. This means on power back up, you have potentially a hundred or more VDSL modems all trying to sync back up at the same time and you end up with a different noise profile, it's like shuffling a back of cards. So the status quo of noise is different, and you can end up with a better or worse speed. As time goes by things may settle back to as before, they may not.

Unfortunately this is the limitation of the technology, it's quite fickle. Roll on having real fibre to the home.

Regards

Phil