DLM system changed?

[James_478]

I've had DLM running on my line a few times since joining Sky and they have started the procedure again, but this time it seems to be different.

I ALWAYS used to sync with an SNR of 7.0db and upon reboot it would always sync back at 7.0 again, the speeds would start low and increase, this time however I am at 6.0db and I have started High, what happens next?

I have always synced between 8.5Mb and 9.2Mb and never ever had any higher, this 1.0db change has now given me these stats:

Broadband Link	Downstream	Upstream
Connection Speed	10231 kbps	945 kbps
Line Attenuation	40.5 db	25.1 db
Noise Margin	6.0 db	14.6 db

Is this going to stick at 6.0db or will they try to take it higher again? I've only been on this 3 days and it's been at 10231kbps for all 3 days.

Also..... Could my upload speed be increased, it looks like there's room for improvement there.

Thanks,

James

[NewsreadeR]

We had heard that it was being tweaked and would allow for lower noise margins, although I am not entirely sure how it works.

Maybe others could help that were aware of it etc?

[James_478]

We had heard that it was being tweaked and would allow for lower noise margins, although I am not entirely sure how it works.

Maybe others could help that were aware of it etc?

I'm just glad I got an extra 1Mb increase at the moment, hoping it stays like that, or gets better. I shall watch it carefully over the next 10 days and report back

[User05]

DLM platform was tweaked back in March if I remember right. DLM in a nutshell:

- Two modes: profile optimisation ('PO') and monitoring;
- Monitors the line 24/7, collates data twice per day;
- If the line is not performing optimally/stable, then profile optimisation is requested;
- This is the same profile optimisation that occurs on new lines;
- Typically starts within 72 hours;
- Still continues to monitor and collate data;
- Sets a new profile based on the data anywhere between 1-6am;
- Lasts anywhere from a few days to 10 or slightly more;
- DLM now uses 3dB/6dB/7dB target downstream SNRs. Upstream target SNR remains unchanged;
- It seems DLM tweaks impulse noise protection higher when first attempting a lower SNR;
- If you see an upstream of 945kbps, then typically impulse noise protection is tweaked a little higher;
- If it's stable, then it'll lift the noise protection which will in turn raise sync speed without change in SNRs;
- When DLM finishes, the settings are locked in unless manually changed;
- SVBN customers: Sky can't set lower than 7dB target SNRs. Only DLM can do this;
- Non-SVBN customers: SNRs are chosen from a drop-down menu. If DLM has set a profile with lower SNRs (3dB or 6dB), then Sky do have the option to choose them manually from the drop-down menu. However, if 7dB if chosen again, then the 3dB and 6dB disappear from the drop-down.

Not much of a nutshell, but will hopefully clear this process up for people in the future.

[James_478]

Interesting, hopefully will see it go to 3.0 db and see what happens. If it's stable I will be a happy bunny

[dgilbert2]

Using routerstats I've often noticed the noise trend below. I assume this is part of the "monitoring" process?

[Isitme]

Using routerstats I've often noticed the noise trend below. I assume this is part of the "monitoring" process?

No that shows that your line is suffering from interference, nothing to do with DLM. It looks like the interference is removed suddenly at one point and your noise margin jumps up. If it returns and repeats this at intervals, then it suggests you may be suffering from REIN.

[dgilbert2]

Thanks Tom, I was thinking that the ramp down of the noise level in such a controlled way was more something that the DSLAM is doing rather than noise/REIN, as I would expect that to be more of a random event?

[James_478]

Thanks Tom, I was thinking that the ramp down of the noise level in such a controlled way was more something that the DSLAM is doing rather than noise/REIN, as I would expect that to be more of a random event?

Well I have to say that I am on DLM at the moment and do not have that, my SNR is pretty stable. Mine has been like this for almost 13 hours

[dgilbert2]

Well I have to say that I am on DLM at the moment and do not have that, my SNR is pretty stable. Mine has been like this for almost 13 hours

Interesting, if you don't see it in the next 11 hours that's my theory up the wall