Something isn't right

[#1]

A few questions,  first some stats:
Router details:
ADSL Link               Downstream Upstream
Connection Speed 6653 kbps 439 kbps
Line Attenuation           30 db         8 db
Noise Margin               16 db 23 db
BT speedtest results:
Download speedachieved during the test was - 1733 Kbps
For your connection, the acceptable range of speeds is 600-7150 Kbps.
Additional Information:
Your DSL Connection Rate :6653 Kbps(DOWN-STREAM), 439 Kbps(UP-STREAM)
IP Profile for your line is - 4500 Kbps
Speedtest.net results:

Data Transfer Speed from Plus.net
Telephone number:
XXXXXXXXXXXXXX
Phone exchange:
CHESTERFIELD
Estimated line speed:
6 - Checked on 2009-11-20 07:40:25
Current line speed:
2000
Questions:
1) How come the connection speed since moving to adsl2+ has dropped from over 8mb to 6mb?
2) How come in the first few days it was up to 10-12mb now it is at 6mb
3) Why is speedtest showing a very low speed at 1.8mb
Thanks.

[#2]

You're right, something's up. It sounds like you have a dropping connection or some interference had caused you to sync at a lower speed. Did you suffer any lightning recently? It may, and I say may be just the 21cn DLM (dynamic line management) causing your sync speed to be going up and down until it finds stable conditions for your line. It doesn't behave as "nicely" as the 20cn one, but I'm no expert on 21cn, I'll point ASBO DOG in your direction.
The low speed test result is totally consistent with the PN profile. Have you change product recently? There is a bug on the product change causing the profile to be set at 2000. If your BT profile holds or goes up, and the PN one doesn't go to at least 4500 in the next 12hrs, hopefully someone on the Comms team will see this and sort it for you.
You should keep your modem/router on 24/7. ASBO will no doubt give a bit more advice.

[#3]

first of all you can request that your upload sync be uncapped (as new orders are now placed on a capped upstream sync due to PN beliveing that the extra upsync can cause downsync problems but as you  can see your downsync is dieing on its arse any way so you may as well enjoy the extra upsync)
unforently with your downstream noise margin looking like its 15db or maybe 18db its very likely your on a banded profile ( bands are new to 21cn and 20cn didnt have them ) am currently in a simalr sittution and ive been on 21cn since last april, yours looks to be in the 3328 - 6656 kbps band
This is where the DLM started its latest mick take out of me http://community.plus.net/forum/index.php/topic,75667.msg664500.html#msg664500
have a read here as well jameseh wrote a good write up on the 21cn DLM and the last section is all about the banded profiles http://community.plus.net/library/broadband/dynamic-line-management-dlm-on-adsl2/
there is talk of the isp's trying to force BTw in to making some changes to the DLM as it seems to place you on a band for the fun of it and in my case it skipped straight past my stable 12db noise margin within a day of it getting brave and droping me to 9db and banded me on 15db noise margin instead of going back to 12db.
maybe anotherone will run through your wiring setup with you to insure thats in the best of order for copeing with the extra frequency's adsl2+ gives just in case your setup could be causing the DLM to band you, most likely it's just this hunk of junk BTw call next gen DLM with extra intellgence 
which router are you running? i ask as it would be useful to get dmt or routerstats running on it to capture some snr graphs to help better understand if there is geniue interfrence on your line

[#4]

Hi ASBO DOG,
Thanks for the reply.  I am currently using a netgear DG834 v1 as my old Belkin wouldn't hold a connection for more than an hour.  I ran what I think you wanted me to run (reading your other posts on the forum)

As for wiring currently it is plugged into the test socket,  I only use 1 phone and dont plug Sky into the phone line.  Changed microfilter as well.

[#5]

ooh err, that definitely looks like noise. Can you hear any crackling or other intermittent noises on the line? If you need. dial a 1 to get rid of dial tone, if you want longer before Number Unobtainable Tone comes on, do the quiet line test 17070 option 2. Do not try any other tests especially ringback. Who's your line rental provider? Is your phone cordless or corded?
With RouterStats, on the Setup Graphs tab, set to Sample every 8 seconds and 900 plots per page (2hrs per graph). This will give a slightly better overview. On the capture tab, define a folder if you haven't, and tick all the boxes.
One tip: If/when you need to reboot or swap things around for testing, powerdown your modem/router and wait several minutes before unplugging anything that disconnects it from the line eg. it's cable, the filter, master faceplate etc. Don't do this more than 5 times in an hour, and then leave it alone for the rest of the day. This is to help prevent the exchange DLM from thinking you have a worse line problem.

[#6]

Hi,
The speed's now set to 4.5Mbps on our side, you'll need to disconnect and reconnect for the change to take effect.
When did you swap over from the Belkin to the Netgear? If it was dropping at least once an hour then chances are that's what's applied the banded profile (a lot of errors or a lot of drops in a sort period of time will cause the DLM to get more aggressive and skip the 9/12/15dB profiles and go to a banded profile). So long as the new router is now stable it will back out the changes and drop the profile back down again.

[#7]

After how long Dave?

[#8]

Hi,
The Belkin kept dropping the connection when I moved to ADSL2+ and was like it for a few days before I changed the router.
Routerstatus is showing a constant 14db now,  no hissing or anything on the line so not sure why it is that high (I take it that is high at 14db?)
BT Speedtest has also changed:
Download speedachieved during the test was - 3937 Kbps
For your connection, the acceptable range of speeds is 600-7150 Kbps.
Additional Information:
Your DSL Connection Rate :6653 Kbps(DOWN-STREAM), 444 Kbps(UP-STREAM)
IP Profile for your line is - 5500 Kbps
Thanks for upping Plus to 4500 but it is still well short of what I was expecting and I got better on up to 8mb than up to 20mb.

[#9]

@anotherone. the first time i got banded it was removed by the DLM after 2 or 3 days, then the 2nd time a week or 2 and the last time just over a month. thats why am kicking a fuss up trying to get mine removed by BTw as i am not waiting a month or maybe 2 month if the trend carrys on when i KNOW FOR SURE my line is stable and allways has bein, just wish the DLM would stop trying for 9db and then puinishing me for its mistake
@floodster, i could advice on some things to check ect but anotherone has a magic touch with getting to the bottom of noise problems, so i will leave anotherone to advise further, so i dont  take you down the wrong road and make anotherone's task harder

[#10]

Looks like it's already made the first change as it's up to 5500 (and on our side too) on BT's side. So I suspect it's backed out the banded profile and set the target SNR to 15dB (which is quite high yeah but better to back the changes down slowly to determine the stability). So long as each change keeps the line stable and doesn't cause too many errors I'd say expect it to drop to 12dB and 9dB over the course of this week and maybe down to 6dB in about 10 days time with each decrease in target SNR increasing the sync speed then a day or so later the IP profile.

[#11]

its likely to raise again thoe dave why there is this interfrence on the line

[#12]

It's going to be interesting to watch this, floodster keep post the graphs and stats as well when you see changes in profile or sync speed.
Those spikes on Sunday's graph look pretty consistent and mainly 2dB dips. didn't appear to start until about 3.30 pm. Any electrical equipment come on at that time. Central heating looks favourite to me with a spike everytime it lights up - any thoughts there?

[#13]

street lights get turned on at that time of day dont they now? fits with the noise on the first graph through the night

[#14]

I suppose it depends on where you are in the country as to what time they come on, but I would have expected more of a continuous noise rather than spikey, UNLESS, it keeps going out and re-striking. Haven't got one of those nearby have you floodster?  Or of course a light on a PIR that keeps going on/off.