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[les-70]

  i guess thats why it is like that.  If any of this is true then I still suspect that the DLM must hope to pick up real los and resync events via the "errors" that are counted. As N* said not telling us which sort of error is counted is far from helpful.  i noticed when doing some severe things to my line that ES  and SES are just not adequate to detect a resync.  You need to also look at los lof and usually a really massive CRC.  Whilst the ZEN statement is helpful re days to react but the rest is close to useless without these details.

[Dray]

To me, its quite simple. Errors are counted as ES and resyncs are counted as resyncs.

[les-70]

  I am sure that resyncs are counted as just that but you can't be sure what the error measure is.  ES seems a guess to me.

[Dray]

I think theres evidence that 2880 ES in 24hours will cause DLM to take action.

[WWWombat]

On the point about what constitutes "an error" in these discussions, I agree that it is the ES counter that is used.

A few years ago, I saw the same kind of thresholds as they applied to 21CN ADSL2+ (attached). However, in that picture, the threshold was termed "MTBE" (mean time between errors), and was set (on the speediest/least-stable option):
DLM intervened when MTBE was less than 60 seconds
DLM de-intervened when MTBE was greater than 600 seconds
DLM stayed put if MTBE was between these values.

An "MTBE of 60 seconds or less" is equivalent to the Zen page stating "no more than one error per minute".

When you look at the error thresholds in terms of "time between errors", you can see how the increments in ES are best used toward calculating the MTBE (by inverting), rather than using increments in the CRC counter.

Note that the BTW 21CN error thresholds are altered 10x between service options, but the Openreach GEA error thresholds only change by 2x.

Note too that the resyncs are handled on 21CN as MTBR.

[Chrysalis]

yep openreach/BTw work on MTBE aka ES.  I even seen a test result posted by plusnet staff yesterday showing MTBE stats.

[adslmax]

I think that is 20 resyncs.

That's misleading. Because My DLM was hit after resync 3 times or 4 times. Not 20 times!

[adslmax]

Standard maps to speed
Stable maps to standard
Super Stable maps to stable

for openreach FTTC

[kitz]

I think resyncs are counted separately. The modem issues a "dying gasp" so DLM can tell the difference between a loss of power and a loss of sync.

Whilst modems may issue a dying gasp, the evidence is that BToR would appear to ignore this..  instead using the 15 min cycle...  which is why we always recommend if possible to leave the router powered down for >30mins, so the DLM sees at least one complete cycle without the router attempting to resync.

 

That's misleading. Because My DLM was hit after resync 3 times or 4 times. Not 20 times!

I agree.. theres way too many people that have been hit much sooner.   iirc TT quote 5th resync will cause DLM interaction for FTTC

[kitz]

On the point about what constitutes "an error" in these discussions, I agree that it is the ES counter that is used.

A few years ago, I saw the same kind of thresholds as they applied to 21CN ADSL2+ (attached). However, in that picture, the threshold was termed "MTBE" (mean time between errors), and was set (on the speediest/least-stable option):
DLM intervened when MTBE was less than 60 seconds

/snip/

Note too that the resyncs are handled on 21CN as MTBR.

Last year we had a major discussion on here re the DLM and I started to put some notes together on what information we could find.
Ummm  I kind of forgot about it..  and its been in its unaltered state now for months...  waiting for me to find some time to research further and add some more info to it.  I must stress that this is the draft form which has been sat around for ages waiting to be finished     But the content so far was checked by one of the guys from PN who confirmed content as valid.

I dont want to publish it properly because its not finished and probably has typos and needs much more work .. but your welcome to look see at what info I do have so far
http://www.kitz.co.uk/adsl/DLM.htm

PS..  Im also of the opinion that it will be E/S

[Dray]

I agree.. theres way too many people that have been hit much sooner.   iirc TT quote 5th resync will cause DLM interaction for FTTC

Is that because TT provision on the Stable profile?

[tommy45]

One thing is regardless of which ISP we the end user really can't be 100% sure which DLM profile our connections are actually provisioned on, All we know is what info we are told be some ISP's ,But there's no evidence to back this up,

Do ISP's have any visibility within the BT wholesale  systems of which DLM profile  is in use for each connection ? or is it a case of them ordering  with a certain dlm profile and assuming that this order has been correctly applied?

 As with the exception of tt and sky  who don't use  BTwholesale and Zen who has  it's own GEA cable links as well as buying from BTwholesale

They would  i assume have visibility for connections that used their own GEA cable links, and be able to change the dlm profile as required

[VDSL2User]

Yes I know that PlusNet have access to BT Wholesale site and hence the users profile data.

I have just transferred my Fibre to PlusNet and as part of the process the following
service event information was placed in my control panel

Provisioning of your ADSL Account Information
 Install diary status changed from Realm configured to Awaiting submission to the DSL supplier
 Automatically set supplier product to WBC FTTC Annex A 20Mbit/s Up, 80Mbit/s Down, Standard Stability

Showing that PlusNet use the FTTC wholesale Standard profile which is Openreach Speed profile for accounts

[NewtronStar]

"A connection should drop no more than 20 times in a 24 hour period"

If so which drops are you allowed 20 of?

Its says 20 drops in a 24 hour period thats ok that works out at under 1 drop per hour close to what B*CAT has said in many posts the 30 minute wait.

Though if I did 10 drops in one hour the DLM would take action even though the remaining 23 hours saw no drops, very confused

[adslmax]

DLM are indeed very confused and no ones will know when it will hit u!