In reply to a post by asbokid:

The Huawei SmartAX MA5616 MSAN has several dozen(?) different 'port' parameters which affect the sync from DSLAM to CPE.

Just to put the cat among the pigeons, Huawei never explicitly refers to DLM, or at least I can't find a reference.

There is however reference to Dynamic Optimisation Profile/.s It seems that the MA5616 can be configured with up to 256 different optimisation profiles, and each profile can be bound independently to one or more ports of a subscriber line card.

Ah, the words of someone who has practical knowledge of the Huawei MSAN's innards!

(And I resent being put amongst a clutch of cowardly flying 'tree rats'. )

Edited by burakkucat (Thu 14-Feb-13 04:31:53)

I have seen reports from users where they have been told their line has a min and max data rate set at the DSLAM by the DLM. In some cases in bad line faults users have been unable to get a sync because the line cannot meet the min rate set by DLM. The min rate seems to be set to half the rate of the max rate whenever its been made known but I am not sure how lines start out, eg. if the 80/20 product had a default of min 40 max 80 then lines that are not good enough to sync at 40 wouldnt work, so I was curious if default profiles are based on estimates but I am not convinced by that either as sometimes starting syncs can vary widly from estimates. So I think the default min and max may well be min 15 max 80. Which only gets changed after DLM detects problems.

If the minimum was 15, which I think is unlikely, then lines that could not reach 15 would not work.
I suspect the minimum starts out as zero.

I have seen reports from users where that has happened, line doesnt sync, openreach installer either aborts or offers to proceed but user accepts the lower speed, and then the profile gets changed to allow it to work. Plus the 15mbit reference in the openreach docs exists.

In reply to a post by Chrysalis:

I have seen reports from users where that has happened, line doesnt sync, openreach installer either aborts or offers to proceed but user accepts the lower speed, and then the profile gets changed to allow it to work.

Where?

I think was on btcare forums but cant find it now, but could have been one of many places as I found a fair few discussion sites.

That sounds more like the ordered product is changed. Infinity has a minimum speed of 15Mbps sync - but that is a BT Retail specification, nothing to do with the underlying GEA product. So nothing to do with what other ISPs do/accept.

Below 15Mbps on BT Retail the customer has to have the "Faster Broadband with Fibre" or whatever its current name is.

ok after checking docs it seems openreach have a minimum of 2mbit sync speed required.

the 15mbit is the prioritisation rate.

so I guess logically the default is set to min 2 and max 80.

Edited by Chrysalis (Thu 14-Feb-13 21:17:55)