Thanks to all for widening the debate on this. I am almost certainly completely wrong about this, but, personally, I haven't seen any actual evidence that provides a convincing narrative (of how these 3 profiles are used) on VDSL, other than in how DLM
might monitor and subsequently react to line conditions.
Yes, I have seen this repeated many times on the net (and always in the same way), but I have yet to see anything that confirms that it actually works 'that way'. I have seen exactly what Ryan quotes, many times, but never with any evidence of how it subsequently influences VDSL DLM. The Zen document, IMO, is merely repeating what the BT GEA SIN itself says, and AFAICS, that is still echoing the original statements in the BT DLM patents (for ADSL). Obviously though, I can see analogies with the 3 'profiles' that were available to EUs as former BE ADSL users.
So, I have no problems with understanding
in principle that an approach like that
could have been adopted for VDSL too. It's just that so far I can see no evidence of how that works in practice.
I can also understand what you are suggesting Kitz when you say
In a weird way its a more simplistic version of the BE DLM.. but then they make it more complicated & interweave added parameters on top of this base profile so that things like interleaving will still kick in - even on the speed profile
I suppose it's
that interaction that I do not, as yet, follow.
I also agree with you, but for a different reason I suspect, when you say
interleaving ... cant be turned off permanently and the ISP has no control over it once the BToR DLM decides you need it
So, being
advocate here, what exactly do we think that such a 'speed' profile might cause DLM to do, if it's not to
avoid the additional delay of using the RS+Interleaving error recovery technique? After all, in all the places that refer to it, it is said (even by Zen) that it is to
prioritise speed over stability for online gamers
And conversely, imagine for the moment I'm on a Speed profile (and a perfect line), and I request that my ISP moves me to a Stability profile instead. Would that switch Interleaving on? I would suggest that it probably would. So, ISP's could then, in effect, have Interleaving switched
on (if indirectly), but then lose control of it, because they then cannot switch it
off again by restoring the EU to the original Speed profile on which (s)he was on just moments before?
Perhaps I am missing something fundamental here, but that all seems irrational to me. But it wouldn't be the first time that I had missed something obvious ....
As a counter-example, we all know from what BS has confirmed, that everyone is initially put on a so-called 'open profile' (e.g. of 80/20, fastpath) on activation, and that (unless things are
really bad) DLM does not intervene to change that until at least 24hrs later. How does the fact that we are all activated in this same state sit with the ISP selection of one these 3 profiles, where according to common belief, Zen selects the Speed profile, while BTR selects the Standard profile?
Finally, PN have told me previously that my profile is '
40M-80M Downstream, Interleaving Low - 10M-20M Upstream, Interleaving Off', which, as I have suggested, is one of the 192
line profiles used by the Huawei DSLAM. No mention anywhere of Stable/Standard/Speed, nor any inkling of how these 'DLM profiles' are translated by DLM to the applicable line profile.
Anyway, that's just the basis of my (hopefully healthy) scepticism about this.
As I have already said, I just don't understand how it is supposed to work as yet.
What would be really interesting would be if anyone can actually request a change between any two of these 'profiles', and the differences can be recorded. We have the tools available to see that.
