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Topic # 202094 16-Sep-2016 12:37
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I'm not too sure if this is the correct forum to be posting on about this, but I hope it is. So my modem currently has an uptime of 32 days. For the past 32 days, my DLM profile has been on a +8ms (or +16ms for total RTT). I woke up this morning to find the donwload sync speed had dropped from 20mb, down to 19mb, and the upload sync speed from 2mb to 1.5mb. My question is: is it better to let the DLM resync my modem like it did without disconnecting it, or to manually reconnect to try and achieve a better sync speed? On one hand I don't want the DLM to think that the new profile is significantly slower, because I'm completely okay with the slightly lower speed (although I would very much like to try and get back the amount lost). But I also don't want the DLM to think the new profile is unstable. I'm probably best to leave it, right?

 

However, last time this happened, the speed dropped to the same it is now, and after 5 days, the DLM went back up? Perhaps it thought the new connection was too slow? No idea, but we had absolutely no issues before on a lower latency profile, so I'd like to try and stay on it this time.

Thanks for any assistance,

 

Chris. 


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  Reply # 1631724 16-Sep-2016 13:00
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With speeds of only 20/2 Mbps on a good day, you have a marginal VDSL connection.
Basically your speed has dropped from "slow" to "slightly slower", and you have told us that this doesn't bother you, and that it has corrected itself in the past.
You have answered your own question - leave your modem alone, and wait.
Do you have a VDSL master filter? - this may help.





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  Reply # 1631732 16-Sep-2016 13:15
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Sideface:

 

With speeds of only 20/2 Mbps on a good day, you have a marginal VDSL connection.
Basically your speed has dropped from "slow" to "slightly slower", and you have told us that this doesn't bother you, and that it has corrected itself in the past.
You have answered your own question - leave your modem alone, and wait.
Do you have a VDSL master filter? - this may help.

 

 

 

 

Well its not so much that I'm concerned about the connection speed NOT going back to normal, but the DLM profile changing to a higher latency profile if I do or don't disconnect the modem.

No master filter right now, but we'll be getting one installed soon. 


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  Reply # 1632004 17-Sep-2016 00:42
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what are your modem stats? the only real reason its going to drop you down is because the error rate on your line is too high or there are frequent disconnects (normally error related but you can fool it by restarting it yourself too many times)

 

post the modem stats


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  Reply # 1632006 17-Sep-2016 00:48
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Install a master filter, avoid disconnections.

 

 

 

If your line is clean, 99% of the time DLM will be more than happy for you to run on DLM-1

 

 

 

Honestly, i wish DLM's latency profiles were slightly less harsh. I do understand the technical reason for the choice of those values however.

 

DLM here mainly works off a linear movement, however is designed to do far more than that. (i say mainly because there are rare cases where simply latency and INP profiles are not the only movements) 

 

 

 

There is quite a technical discussion that can be had on the topic, however i suspect that is a little outside of this thread.





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  Reply # 1632009 17-Sep-2016 01:34
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Jase2985:

 

what are your modem stats? the only real reason its going to drop you down is because the error rate on your line is too high or there are frequent disconnects (normally error related but you can fool it by restarting it yourself too many times)

 

post the modem stats

 



Current uptime is 32 days, (shows on homepage but not here) sync time was the same as the uptime until last night. However, current sync is just over 21 hours (DLM re-synced sometime last night).

 

 Modem Stats

 

 

 

The uptime pretty much backs up the stability of the line thus far. It's not the fastest speed, but with low-end VDSL, and fibre not available yet, its the best we can achieve (until we get a master filter which might boost it a little). I just don't know if I should restart the modem to try and get the sync speed higher, or to leave it and sort itself out. Like I said above, this happened a few weeks ago, but after 5 days, the DLM latency increased (although it was 100% stable, with no DC's). Perhaps it was detecting errors? Or thought the lower sync speed wasn't acceptable, so it reverted? 


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  Reply # 1632052 17-Sep-2016 10:46
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uptime is the time the modem has been on, this doesnt mean much, sync time should match up time on a stable line

 

you are on DLM1 going off those stats, thats where DLM aims to get you. Generally this involves sacrificing a little speed to get you there.

 

You line seems to have a few errors on it, and i think installing a master filter, tidying up the wiring from the ETP and installing a dedicated VDSL jack should help a bit, and may get you some more speed and hopefully stay on DLM1

 

But with that attenuation 26.5dB i wouldnt hope for much more speed.


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  Reply # 1632126 17-Sep-2016 11:33
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Jase2985:

 

<snip>  ... i think installing a master filter, tidying up the wiring from the ETP and installing a dedicated VDSL jack should help a bit, and may get you some more speed and hopefully stay on DLM1

 

But with that attenuation 26.5dB i wouldnt hope for much more speed.

 

 

+1

 

As above, with a downstream attenuation of 26.5db you will always have a marginal connection.

 

You can probably improve it with a master filter etc - I would definitely install one if it was my connection.





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  Reply # 1632209 17-Sep-2016 17:10
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With DLM1, on a marginal line it is not uncommon to be slower.

 

 

 

I recall a reasonably decent line i was on in once place, where the line was unfiltered - i did not stay there for long, landlord was an utter twat about any modifications to wiring.

 

the error rates were actually high enough that i could feel the re-transmits causing a bit of an issue. Downstream was 10mbit faster on DLM-2/4

 

 

 

What i ended up doing there, was snr tweak the connection high enough that it would not even try to drop down to DLM-1 but hold at DLM-2

 

 

 

In that case, the sacrifice of latency was worth it for consistency of packets.





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Any comments made are personal opinion and do not reflect directly on the position my current or past employers may have.


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