In reply to a post by RobertoS:

I'm hoping that after a period of stability with my new modem DLM will remove the banding.

The line will need a DLM reset to remove the banding, it doesn't remove itself anymore.

Edited by deleted (Sun 22-Jan-17 16:16:42)

Anything to back that up please?

I've seen one reduction already, as (I think) I've posted. We have also recently seen on these forums other stepped reductions.

That's new, sorry I was just going on several reports from users on broadband forums. Yes, you may see a reduction in DLM retention but not necessarily banding.

Edited by deleted (Sun 22-Jan-17 19:21:14)

DLM retention? What do you mean by that?

Banding is auto removed on lines that are stable but had some major problem. It typically takes 2-4 months though.

On lines with a fault causing it to be banded then if handled properly by the engineer who fixes the fault it should be removed immediately with them requesting it from their control centre. If that isn't requested when closing off the fault though, then it's back to wait and pray.

I mean the loss in the strength of DLM's actions.

That's interesting, maybe something has changed because in the past, DLM used to band lines very quickly without applying other forms of pretection first, which as we know what DLM applies to a line first is removed last, but banding was never removed until a DLM reset was performed on some lines.

Banding certainly "sticks" on some lines. There's examples on MDWS where lines have been stable and ES rates have been well below the assumed limits for over a year, yet the banding has not budged. It does still work correctly sometimes though. Usually banding drops in stages, though it may not completely disappear.

I see no point rushing to ask for a DLM reset if the banding is say 35mb on a usually 37mb line. Such banding on a 60mb line is a different matter.

In reply to a post by RobertoS:

Banding is auto removed on lines that are stable but had some major problem. It typically takes 2-4 months though.

Banding used to be auto-removed, as you say. It used to take a while before reductions were considered, but the eventual removal would happen.

Since the middle of last year, when banding functionality seemed to be triggered more regularly, and banding increases (ie increasing severity) were applied more regularly too, we've seen that very bad cases do indeed get auto-reduced in severity. But the evidence is still that such reductions rarely continue on to a final removal of banding.

It was most noticeable last year, with changes in the G.INP switch-on mechanism. A line appeared to need DLM to fully undo all interleaving and banding settings before it would allow G.INP to be turned on instead. Yet banding seemed to be very sticky, and needed DLM resets.

Your line is one example, while the last report from @darrelr is another.

IIRC, @William's line was one caught up too, until he got a reset done.

I hope for this evidence to change. Banding that sticks permanently, even after temporary or accidental problems, is just not useful. Especially with such draconian requirements on getting a DLM reset performed.

Thanks, but . That's bad news. You think both darrelr and I are stuck by the sound of that.

I'm still going to give mine a while, seeing as it's previous long-running banding was 60Mbps. Though the more I think about it, and with this latest view from you, I may need to see what can be done.

Let's hope things change, as that's not how DLM should work. You could say my example was accidental, well no not really. XD.

Edited by deleted (Mon 23-Jan-17 12:55:54)

In reply to a post by WilliamGrimsley:

because in the past, DLM used to band lines very quickly without applying other forms of pretection first, which as we know what DLM applies to a line first is removed last, but banding was never removed until a DLM reset was performed on some lines.

What you are referring to as "in the past" seems to have been 2016 behaviour. If I remember correctly, your line was one of the early ones where we realised that banding had become (a) a choice that wasn't last resort, and (b) very very "sticky" (ie not removed).

That change in behaviour seemed to coincide with the 2nd attempt at putting G.INP on ECI cabinets. It also loosely coincided with BT reaching agreement with Assia over the DLM patent case. Whether those observations are a coincidence or causal, we don't (and won't) know.

@RobertoS is referring to behaviour prior to 2016, which is long-standing behaviour that we had all become very used to.

I wonder whether we'll see a new change in behaviour this year? We'll have another attempt at G.INP on ECI, and of course we have the rollout of lower SNRM targets too.