Sorry, that's what I meant.

In reply to a post by lee111s:

No, you THINK a fault is developing because you have a slightly fluctuating noise margin and a few errors.

No loss of sync or noticable affect on throughput = no fault.

Actually, the changes in the last day (aside from the ongoing 3dB trial) do point at something suspicious happening. There is a huge increase in FECs and a huge increase in retransmission counts, which have increased further with today's switch from 4dB to 3dB.

Error protection has been working extra-hard on that line in the last day.
https://s30.postimg.org/l7y42l1hd/William3db_And_Odd...

But, while something is happening under the hood, there is little extra evidence appearing at CRC, ES or LEFTRS level. There's no impact to the service.

(I am impressed, actually, at just how little is getting through)

Of note to people watching the 3dB trial: Whatever has happened over the last few days didn't happen on the first run through the 6-5-4-3dB steps. And DLM seems to have allowed the 3dB step to happen anyway.

@william:
On the main part, though, @lee111s is right - it isn't really a fault until it becomes an actionable fault. Up until that point, it really only classes as "normal behaviour that DLM is designed to cope with".

On the data side, you are a long way from an actionable fault. Your speed needs to drop hugely to get there.

However, on the telephony side, you already have an actionable fault. If you can hear things on the line, then it is something your telephony provider should react too. At a minimum, they will run some copper tests. (Note, as ever, it is important not to confuse them by mentioning any broadband problems at the same time).

I had this kind of issue a couple of weeks ago. Plusnet (my ISP and telephony supplier) have a webpage that triggers the line test. The webpage ran the test, but failed to tell me the result. However, behind the scenes, it had logged a fault with Openreach, and organised a fix. Someone was out fixing that a day later, with no need for an appointment.

That issue caused noisy crackles on the line. Nothing faint or subtle about them. But they didn't affect broadband. I expected an E-side problem. Imagine my surprise when, after chatting to the engineer, the issue was on the D-side.

QLT? Unless that also means something else!

Very interesting. Thanks for explaining.

Hi

My line did this, went from almost a flat line to looking like an ECG graph, but not varying enough to cause any resyncs or problems.

It coincided with BT Openreach digging up a trench next to the cab and running a generator for the traffic lights (or so it seemed to me), so went back to normal when they finished.

The point is VDSL is a hack to get data over wire not designed to carry data, so it's flaky and susceptible to all sorts of noise which can come from anywhere. This is precisely why we have a margin, so that things like this the line can just ride across.

Not much you can do about it, and expect things to change over time with the charts and how your line behaves, its the nature of the beast.

Regards

Phil

Ah, I see. There's no work going on near the cabinet. I will keep monitoring without getting too fixated on it, honestly I find this really interesting.

Edited by deleted (Thu 09-Feb-17 16:57:38)

Have a read of this page, right to the end. There's quite a lot needs updating on the site but most of the principles are still the same.

In reply to a post by WilliamGrimsley:

Do you think a fault is starting to manifest itself though?

Personally I think not, I feel something has just changed externally, whatever that is, it is not service affecting and hence stop focusing on it.

My line goes through a lot worse variations, but I am in London with a lot of external factors changing.

Ok.

Well, to say there are whistles on the quiet line test, I think something's up.

So report it as a noisy line fault.