sync decrease after some months on trial

[#1]

Hi All,
After being on the trial now for several months (easter-ish) and having a sync around 11Mbps I have recently (in the last couple of weeks) seen it drop to 7Mbps.  After the initial few weaks of training the 11Mbps was quite stable and similarly the 7Mbps appears also to be quite stable.  I didn't notice any form of gradual decrease, just one day 11 next 7.  I have an uncapped upload speed of almost 1.2Mbps which has been pretty stable since it was uncapped a few weeks after I moved onto the trial.  SNR look similar although I didn't note them at the time (oopps).  Current stats;
                                        Downstream      Upstream
Connection Speed           7101 kbps         1141 kbps
Line Attenuation               24 db                 7 db
Noise Margin                   16 db                    4 db
My question is simple, where have my 4Mbps gone and, more importantly, how do I get them back?
-tony

[#2]

Are those stats shortly after restarting the router? If you haven't recently restarted the router I suggest trying this.
The downstream SNR (noise) margin seems very high. If the target SNR margin really is that high that is the cause of your low sync speed.
David

[#3]

HI,
Yes all the stats are stable after restarts and even and overnight powerdown.  Now you mention it the downstrem noise margin used to be much better than that.  I'm pretty confident that things are good at my end - I have the router plugged into a fairly new NT5E replacement adsl plate which hasn't changed - so any change would have to be on the line.  Can I get BT to run a test or up the gain and is this likely to help?
-tony

[#4]

Hi
I to have been on the trial since early May, I to have seen my sync speeds drop from 10meg with s/n of 6db,
(Att 40.5db)
The Dslam then daily (about 8ish) would drop sync and try various target s/n ratios,down to 3db, when 3db failed
as it would ,it put me up to 12db, then 9db, been 9db for weeks now,
What it won't seem to do, is go back to 6db where it is always had been,and was fine at 6db all day and all night long
So all in all I am about half a meg faster down,but at 6db it would sync in the high 8 megs
Trouble is because it insists on near daily re-syncs, My profile never catches up!
Synced at 7607 ATM but profile is 5.5meg and has been for weeks I believe
Later

[#5]

Glad/sorry to see someone else experiencing such fluctuations.  Is there any way to prompt the DSLAM to change it's behaviour?  I guess the only weapon we have is re-connecting so does it have any effect if you power cycle repeatedly or break connection for 24 hours etc?
-tony

[#6]

After having a solid sync of over 21mb since the start of the trials in past 3 weeks  I am synching at 18272.

[#7]

After having over two years of solid connection speeds in excess of 4MB I joined the trial and after the initial training period my speeds then settled around 6.5 > 7.5MB. But my luck did not last. Suddenly they have plunged to 3 > 3.5MB, this is less than I was getting in 2007!
Following the amount of 'Ticket Tennis' played at the start of the trial I have seriousley lost all interest in Broadband, I used to catch up with a few programs on BBC iPlayer but my pleasure has now been adulterated by a constant stuttering connection, and the tennis isn't on so that cant be blamed. The only up side is my upstream speed as trebled.
My present contract with Plusnet is finishing within the next three month, So I think I will be either going LLU or cable, I dont blame Plusnet fully, I have been with them for nearly five years so they cant be all bad. The problem as far as I can see is BT's archaic copper wire system.

John B.

[#8]

Hi John,
Are you talking about the general broadband speeds or are we talking about sync speeds?  If it's sync speeds then thats just from your router to the exchange and not dependant on any other ongoing activities (like the cricket/tennis/randomthingsgoingonintheworld).
Sounds initially like a change in the DLM, which seems to be somewhat volatile on ADSL2+.

[#9]

Quote from: Jameseh

Sounds initially like a change in the DLM, which seems to be somewhat volatile on ADSL2+.

I think you have hit the nail on the head James. I was talking about my variable sync speeds, it is just annoying that my once stable connection is now so erratic.
John B.

[#10]

John - How recently did the downturn in speed happen?
The DLM should recalculate after about 3 days.

[#11]

Quote from: Jameseh

John - How recently did the downturn in speed happen? The DLM should recalculate after about 3 days.

My Download speeds dived on June 25th and are still dropping my actual Sybnc speed is just begining to level off around the 5MB area. My downstream boise is anywhere between 16 and 12db it used to be between 4.5 and 8db prior to the trial it was a rock steady 6db 24/7 without a drop out or any other problem.
John B.

[#12]

Thanks John.
I take it you're wiring into the master socket with all of your telephone devices filtered and all the usual?
Is the any detectable noise on the telephone line itself?

[#13]

You may have to sit it for a couple of weeks. Believe most users are seeing this after a few weeks on the trial, I know that I have. The DLM seem to up the SNRM and decrease/switch off interleave. This is what happen with my line, the SNRM went up to 15db and interleave depth to 0 with sync speed down to 2500kbps. Then after 2 weeks the SNRM went from 15db to 6db and interleave depth from 0 to 160 with a sync speed of 4881kbps. This was yesterday and after a few resyncs today the SNRM has gone up to 9db and the interleave depth to 32 with a sync of 4232kbps.
With the length of my line and the attenuation the current values is where I think I should be. So be interesting if the DLM will maintain them.

[#14]

No audible noise on the line and all filters were changed in April and the speeds reached 8MB + at that time, had a few dropped connection for a period but everything bottomed out and I was getting 7MB+ with a profile of 6500, my profile at present is 3500.
Since June 25th thing are getting worse. Most of the time I am using my O2 wireless connection just to guarantee a steady speed. My usual monthly usage was in excess of 40GB+ this month due to the drop my usage is unlikely to even reach 16GB.
John B.

[#15]

My downstream SNR increased to 9.5 dB on 20th May and has remained like that ever since.  I've been on the trial since last December and I'm now getting the lowest speeds I've had since being on the trial.  Prior to 20th May my IP profile fluctuated between 10,000 and 11,000 kbps (borderline sync speed).  Since 20th May my IP profile has been as low as 7,150 and is now 8,000 kbps.  Even though my line is stable the DLM system has not restored my target SNR to 6dB.
Upstream sync speeds tend to be 447kbps and 855kbps on alternate days!  (I switch my router off each night)
The erratic nature of ADSL2+ is its Achilles heel.