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[j0hn]

https://www.openreach.co.uk/cpportal/updates/briefings/superfast/nga00621

This briefing is to inform all CPs that Openreach will soon be offering CPs a chance to trial a different DLM Stability Policy.

Considering they have had the exact same 3 policies for a decade of FTTC I thought this was interesting.

Would be interested if anyone was able to get further info on this.

[meritez]

TTB took part in the last one, poking a couple of people:

Changes in Openreach Dynamic Line Management

Dear Partner,

We have been notified by Openreach that they will be conducting a mandatory field trial of some new FTTC DLM profiles from 16th January 2017. These new profiles will use Signal to Noise Ratio Margins of 3, 4 and 5dB instead of the usual 6db and are designed to help stable, error free lines to achieve greater downstream speeds. The trial will cover all variants of FTTC, including EoFTTC.

How will the new DLM profiles improve a FTTC service?


The new DLM profiles have the potential benefit of increasing the speed of existing FTTC connections.

Openreach have been trialling the profiles with TalkTalk, and other CPs, for several months and there are currently just under 600 TalkTalk Consumer lines using the new profiles. During the time they have been in use we have seen average speed increases of up to 4Mbps on lines that have been moved to the lower margin profiles with no increase in customer contact or fault rate. In the case of lines where increased errors have been introduced due to the lower margins, the Openreach DLM system has acted accordingly and moved them back to profiles with higher margins to reduce the errors again.

When is this trial taking place?

Encouraged by the positive results seen during the Industry trials, Openreach are going to introduce the new profiles at 150 exchanges in the Somerset and Dorset region from 16th January 2017. They anticipate that approximately 10% of the FTTC lines on these exchanges will see a profile change and therefore an increase in their connection speed. Following this logic, we expect to see around 300 Partner lines benefit from the lower margin profiles across the trial exchanges.

Once the new profiles have been enabled at these exchanges, DLM will automatically start to apply them to the lines that can benefit. Lines that are not suitable for the lower margin profiles will not be changed as DLM will be following its normal rules of engagement and only trying to optimise lines with very low/no errors and retrains. Once the new profiles are in place and being used, DLM will action any increase in errors that break thresholds as it does today, with a check every 24hrs to ensure lines are performing as expected and a change of profile if they are not.

Our technical teams have been briefed and will be monitoring line performance during the trial period. If any lines are identified as being negatively impacted by this change they will have access to an immediate investigation process that Openreach have put in place. Given the results of the profile use so far, and DLM’s monitoring, neither Openreach or TalkTalk Business are expecting to have to use this process, it is there purely for our customers’ peace of mind.

The trial will run for approximately a month and, if successful, Openreach will roll out these profiles to all exchanges in the UK and Northern Ireland later in the year.


What do I need to do?

You don’t need to do anything. This notification is simply to make you aware that the trials are being undertaken and we will provide further updates on the DLM trials in future. We hope that you find this enhancement to the service useful and see the benefits we envisage it will bring to your operation.

[j0hn]

Ah, the XdB trials. That was slightly different.
TTB didn't exactly "take part" in that "mandatory" trial 

That was trialling 3, 4 and 5dB on Huawei lines, on the existing DLM policies.

Currently we have the Stable, Standard and Speed policies.
It's been the same 3 policies since FTTC launched.
There's also a custom policy but that's only meant to be used on ISP test lines.

The above briefing is about the introduction of a whole new DLM policy
Hopefully it's a policy that allows some manual tweaking of the profile in use.

[meritez]

The other notification I have is:

We are writing to you as Openreach will be running a Proof of Concept to test an adjustment to their Standard Dynamic Line Management (DLM) stability policy. The Proof of Concept starts on Monday 17th September 2018, and will affect all FTTC lines provided from this date.

 

What does it involve?

Currently DLM employs three stability policies: ‘Speed’, ‘Standard’ and ‘Stable’. The Proof of Concept will:

+ Adjust the error threshold of the ‘Standard’ policy so it is more evenly spaced between ‘Speed’ and ‘Stable’
+ Re-profile a line in an attempt to improve its stability if the Mean Time Between Errors (MTBE) is <60s for the ‘Standard’ DLM policy
+ Test the new MTBE levels at 120s, 150s and 180s

 

The Proof of Concept should provide more stability to your FTTC lines, and with Openreach we will be monitoring these to ensure there is no adverse impact.

 

When will it start?

This will begin on Monday 17th September 2018 and will last approximately 11 weeks, finishing on Friday 14th December 2018.

 

What product does it apply to?

It applies to all FTTC lines provided after Monday 17th September 2018.

 

What will happen once the Proof of Concept is completed?

Once volumes of around 300,000 have been included in the Proof of Concept, the FTTC lines will remain on their modified error thresholds until Openreach make a decision regarding the new threshold limits for the Standard Dynamic Line Management policy.

No responses to my pokes yet

[adslmax]

Would be nice if Openreach to trial scrapped DLM on FTTC / G.fast 

[g3uiss]

Would be nice if Openreach to trial scrapped DLM on FTTC / G.fast 

The DLM is there to provide a stable service

[adslmax]

The DLM is there to provide a stable service

I know but still EVIL DLM thought. 

[renluop]

The DLM is there to provide a stable service

Quite appropriate for some connections with Steptoe and Son speeds.

[GigabitEthernet]

What is "evil" about DLM?

[kitz]

Max,  I've said this numerous times before.   Please listen and take onboard the following.

RaDSL -Rate adaptive dsl (such as adslmax/adsl2/vdsl/fttc/g.fast) NEEDS a DLM to be able to work.  Without it we would be stuck with fixed rate speeds like we used to have in the days of 512/1Mb/2Mb where lines would either work OR they wouldn't. 

ADSL Max (like your name!) was the first RaDSL product in the UK.  It came with a DLM.  Admittedly it was a lot more basic than some of today's DLM profiles but it still had the Interleaving and RS Error Protection. It suddenly meant that lines which previously had not been able to hold a 1Mb or 2Mb connection may now be able to sync at say 2Mbps or even higher.

If Openreach scrapped DLM it would be a massive disaster - many lines would become unusable and keep losing sync and lost data packets.  Its the DLM that keeps so many lines connected.
Not all lines are very short like yours and can sync at full rate.    Just because Max doesnt need a DLM does not mean that hundreds of thousands of lines in the UK doesnt either.  Just think for a moment, without some sort of DLM in the background ready to kick in if needed, then your line would not be fit for the 330 g.fast product.   

Please no more of the silly 'Openreach need to ditch DLM' comments.   
1) It shows a lack of understanding of DSL and makes you look stupid.
2) It's a selfish attitude. 


Not all of us may like what the DLM can do on an otherwise stable line, but on the whole it does what it is supposed to and keeps many lines stable.   Openreach's DLM is harsher than some,  but conversely its also more sophisticated than others and allows things like 'x'dB and g.inp.   I'm quite sure you like those bits of the DLM. 

[kitz]

Thanks Meritez but I think those are both old news.   


I'm not certain if this is related to NGA0006/21...  but I do know that last year they were experimenting with the time periods that the DLM ran for.  Going back further they experimented with 2 day DLM averages, but eventually settled on 24hr period from 8pm (not midnight).  Anyhow last year they suggested the possibility of only monitoring for DLM during peak times.   

The idea behind this is that most instability tends to occur in the evening. So the new system only monitors for errors during say 6pm > 10pm and Errors are averaged out over this 4 hour period.  The MTBR and MTBE figures will be adjusted accordingly.   Its supposed to be advantageous in that any occasional blips that occur at other times of the day are ignored.    I think I may have mentioned it briefly last year and they did have a specific name for it, but I've totally forgotten now what they called it.   Sorry too tired, hurting and brain not functioning to recall anything else right now. 


----
ETA
Just remembered the name - it was Temporal DLM  - and now that I have remembered the name, it was a bit longer ago than I thought.

[tiffy]

Max,  I've said this numerous times before.   Please listen and take onboard the following.

Your patience with and tolerance of this "character" is unbelievable but I fear a lost cause!

However, many thanks for the DLM refresher, I'am sure appreciated by the many forum patrons who actually listen, take on board and attempt to understand the information so freely offered by someone who obviously knows their subject.

[broadstairs]

Your patience with and tolerance of this "character" is unbelievable but I fear a lost cause!

However, many thanks for the DLM refresher, I'am sure appreciated by the many forum patrons who actually listen, take on board and attempt to understand the information so freely offered by someone who obviously knows their subject.

Hear hear.....

Stuart

[kitz]

A small update on this.   I must stress that I can't take credit as I'm not responsible for finding out the info, but just to let you guys know that its nothing to do with any of the previously mentioned posts... and it is more like a new Stable profile with new parameters.     

However, there is something that is a wee bit ambiguous that requires clarification.   Once this info has been obtained, then the relevant person who has done the hard work of digging, can let you know.   I just didn't want any speculation about something its not in the meantime.   

[adslmax]

I spoken to engineer about this one today at my parents line fixed today but he told me DLM system are much better than before, more stable. We shall see. He told my parents that Openreach FTTP for their area could be few years away. (funny he the same guy who did my g.fast installed) small world 

I did asked him about if there possible bonded G.fast paired, he laughed off and say No, Openreach won't allow it at present. My parents told me to shut up.