The three DLM modes is a FTTC thing. 21CN WBC ADSL2+ is a very different beast

I knew it was one way round, been quite a few years since I worked with and xDSL products.

Is it something ISP's get to choose at the point of ordering for each customer? Or is it something Openreach decide depending on each line? Or do ISP's have a "blanket" policy for which DLM profile they want all of their customers on?

ISP's have a "blanket" policy for which DLM profile they want all of their customers on?

ISPs seem to have a "blanket" policy for all of their customers. I have yet to see an ISP change DLM setting for an individual customers on FTTC, not sure if this is actually possible though.

DLM profiles (the 3 profiles) is forced on ISPs... ISPs cannot change outside of these, ie make manual adjustments from their end... Hence why getting things such as "fast path" etc on FTTC is not really a thing.

IE I cannot be on FTTC and request my ISP to set me on fastpath with a 3db noise margin, the provider cannot guarantee that, DLM just does its thing. on ADSL2+ over LLU, adjustments could be made on many ISPs.

Edited by ukhardy07 (Thu 31-Mar-16 14:30:24)

Yeah I used to work for an ISP and we had control over interleaving, noise margin etc on ADSL but not with FTTC. It's coming back to me now about the 3 FTTC DLM profiles. Speed, stability, or a compromise of both being the 3 available.

I suspect almost all, if not all ISP's have gone for the middle ground.

I think the options are

BTW "Standard" = Openreach "Speed"
BTW "Stable" = Openreach "Standard"
BTW "Superstable" = Openreach "Stable"

TalkTalk use Standard
When I did FTTC trials for Sky they used Stable

Not sure of other ISPs.

plusnet, BTr, zen, aaisp - speed
sky - standard
talktalk - stable?

not sure about the talktalk one hence the comment.
Sky were changing the profiles for fiber pro customers on demand but then started becoming stubborn (probably due to upper management putting a block on it), they will still do it if pushed but not as easy as it used to be.

Generally the profile is set when the line is ordered, isp's can switch the profile at any time, but they are all resistant to doing it.

Others have answered "better" but here is my simpler answer:

No, the speed varies a *lot* between providers. The connection between you and the exchange will be a bit different depending on the settings the ISP chooses in the balance between speed and reliability, but that doesn't make all that much difference.

There is a lot more difference between ISPs in the speed and capacity of the connection between your exchange and the internet. Some ISPs throttle data speeds at busy times. Some ISPs simply don't have the capacity to carry all the traffic for their users.

To an extent you get what you pay for. I use Zen and have found them consistently good (they are on record as saying they never throttle) but it is possible that from your local exchange they (or any other ISP) could have capacity issues.

When I moved from a different ISP back to Zen, the difference was significant..

Which ISP are you with at the moment? We could perhaps advise on how they are viewed wrt performance compared to others, and support if there are problems with the connection.

Is this true for Market 1 exchanges? Or does a Market 1 exchange only have BT backhaul connected to it?

There's no such thing as a Market 1 exchange