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20CN to 21CN Speed Decrease

pmarti22
Grafter
Posts: 43
Registered: 22-11-2013

20CN to 21CN Speed Decrease

Reposted, as finally noticed the new topic button.  Sorry.
I have an problem when the change to ADSL2+ occured that my sync speed does not match the possible max speed that my attenuation and SNR shows is possible.  It's even lower than was seen on ADSLmax.  I had a rock steady sync of 7200kbps at 38dB attenuation with a 6dB SNR which varied very little.  Since changing to 21CN, the attenuation has increased to 42dB (this was know about a slight increase as they calculate it differently) and my SNR is still practically 6dB.  Varies 0.1 or 0.2 +or- over the course of the day.  According to the calculations from either Kitz or Mr Saffrons, my attenuation of 42dB and my steady SNR, should sync around 10mbps.  As of today its around 6750kbps this morning.  I download the router stats from Sunday and are as follows.  I have a very good upload speed, but ask why my sync speed has now dropped off??  Any ideas?  Someone did suggest going back to ADSLmax, but routed over the ADSL2+ network as that provides constant signal power and not the varied power levels of 21CN.  I live on a almost finished new estate about 3km from the exchange in a nice rural straight line, so all connections are new and there is only a single phone connected and the router to the main new style OpenReach socket.  Running out of ideas with this.......  2 kids on iPods and the wife on iPlayer makes for an unhappy dad......  I have a new RJ11 router cable on order to replace the standard non-screened cable, but help or checks you can perform would be appreciated.
Thanks
DSL Type: ITU-T G.992.5
Bandwidth (Up/Down) [kbps/kbps]: 1.127 / 6.923
Data Transferred (Sent/Received) [MB/MB]: 3,52 / 14,20
Output Power (Up/Down) [dBm]: 12,6 / 0,0
Line Attenuation (Up/Down) [dB]: 24,8 / 42,0
SN Margin (Up/Down) [dB]: 5,9 / 5,8
System Vendor ID (Local/Remote): TMMB / ----
Chipset Vendor ID (Local/Remote): BDCM / IFTN
Loss of Framing (Local/Remote): 0 / 0
Loss of Signal (Local/Remote): 0 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): -
Error Seconds (Local/Remote): 3 / 0
FEC Errors (Up/Down): 0 / 0
CRC Errors (Up/Down): 0 / 3
HEC Errors (Up/Down): 0 / 8
13 REPLIES
Community Veteran
Posts: 38,460
Thanks: 1,027
Fixes: 62
Registered: 15-06-2007

Re: 20CN to 21CN Speed Decrease

post in the other thread removed
To answer the question with a question
How long has the line been in sync - when was the last resync
Community Veteran
Posts: 26,686
Thanks: 910
Fixes: 10
Registered: 10-04-2007

Re: 20CN to 21CN Speed Decrease

Going back to ADSL Max isn't an option. http://www.dslchecker.bt.com/adsl/adslchecker.welcome will tell you when it is being turned off in your exchange. It will say something like:
Quote
The Stop Sale date for IPstream is from 31-Oct-2013; the Formal Retirement date for IPstream is from 30-Jun-2014
jelv (a.k.a Spoon Whittler)
   Why I have left Plusnet (warning: long post!)   
Broadband: Andrews & Arnold Home::1 (FTTC 80/20)
Line rental: Pulse 8 Home Line Rental (£13/month)
Mobile: iD mobile (£4/month)
pmarti22
Grafter
Posts: 43
Registered: 22-11-2013

Re: 20CN to 21CN Speed Decrease

Quote from: Oldjim
post in the other thread removed
To answer the question with a question
How long has the line been in sync - when was the last resync

Thanks.
The current sync happened yesterday afternoon, so maybe just under 24hrs.  Previously after the 10day period, the sync maybe lasted 2 to 3days before dropping.  On 20CN it lasted weeks.
pmarti22
Grafter
Posts: 43
Registered: 22-11-2013

Re: 20CN to 21CN Speed Decrease

Quote from: jelv
Going back to ADSL Max isn't an option. http://www.dslchecker.bt.com/adsl/adslchecker.welcome will tell you when it is being turned off in your exchange. It will say something like:
Quote
The Stop Sale date for IPstream is from 31-Oct-2013; the Formal Retirement date for IPstream is from 30-Jun-2014


My details bring the following.
The Stop Sale date for Datastream is from 30-Jun-2012; the Formal Retirement date for Datastream is from 31-Mar-2014. The Stop Sale date for IPstream is from 31-May-2014; the Formal Retirement date for IPstream is from 30-Nov-2014.
Exchange TAKELEY is served by Cabinet 9
WBC ADSL 2+ Up to 3.5 -- 2 to 6 Available
WBC ADSL 2+ Annex M Up to 3.5 Up to 0.5 2 to 6 Available
ADSL Max Up to 2.5 -- 1.5 to 5 Available
But if I use a house less than 50metres away the results are different, although same cabinet but very slightly closer and nearer the speeds that I assumed I would receive.  My upload speed seems to match this, or is it that I am currently uncapped hence the lower sync speeds??  My details show I should only get upload speeds of 500kbps even when uncapped?Huh
Exchange TAKELEY is served by Cabinet 9
WBC ADSL 2+ Up to 7 -- 4 to 10 Available
WBC ADSL 2+ Annex M Up to 7 Up to 1 4 to 10 Available
ADSL Max Up to 4 -- 3.5 to 7.5 Available
Fixed Rate 2  -- -- Available

Thanks
Community Veteran
Posts: 5,109
Thanks: 465
Fixes: 17
Registered: 10-06-2010

Re: 20CN to 21CN Speed Decrease

You can't go back to 20CN but you could just set your router to ADSL2 or ADSL1 rather than the default auto resulting in ADSL2+. I think it has to be set via telnet:
[tt]xdsl config multimode=adsl[/tt]
or
[tt]xdsl config multimode=adsl2[/tt]
or
[tt]xdsl config multimode=adsl2plus[/tt]
pmarti22
Grafter
Posts: 43
Registered: 22-11-2013

Re: 20CN to 21CN Speed Decrease

Thanks.  I have just searched the above and found a very good guide for this via http://npr.me.uk/telnet.html  The commands are very slightly different, but shows how to activate the Telnet sessions.  Not used any of these commands since college days and compiling and debugging.  Should be fun, but will take a backup just incase I brick it......  I think there is a command in there that shows whether the Annex M is activated.  Unless someone can confirm to me its not on??  Otherwise it shows that my download sync is out if I can sync that fast for the upload without the uncapping and what my download should be syncing at.
I will give it a go later this evening.
Thanks
dick:quote
pmarti22
Grafter
Posts: 43
Registered: 22-11-2013

Re: 20CN to 21CN Speed Decrease

Quote from: ejs
You can't go back to 20CN but you could just set your router to ADSL2 or ADSL1 rather than the default auto resulting in ADSL2+. I think it has to be set via telnet:
[tt]xdsl config multimode=adsl[/tt]
or
[tt]xdsl config multimode=adsl2[/tt]
or
[tt]xdsl config multimode=adsl2plus[/tt]

Right.  I manually forced the router into each mode and then viewed the specs.
ADSL Mode - up 1120kbps, down 6912kbps.  38.5dB down attenuation, 6.1dB SNR & 19.9dBm signal power.  Connected in fastpath.
ADSL2 Mode - up 1123kbps, down 6887kbps.  38.5dB down attenuation, 5.6db SNR & 20dBm signal power.  Connected in interleaved mode.
ADSL2+ Mode - up 1123kbps, down 6771kbps.  42db down attenuation, 6.2dB SNR & 0.0dBm signal power.  Connected in interleaved mode.  This signal power I cannot work out why its zero.  Anyone??  Every other router stats I have seen show a value for this.  Is it that my router is faulty hence why it does not like ADSL2+ mode?
From my connection to ADSL via the 21CN, my IP profile is 6.1mbps and follows the same percentage rule as ADSL2 as they were 6.08mbps for ADSL2 and 5.97mbps for ADSL2+.
PlusNet support staff: Are you able to please send me a latest level TG582N router??  My current one is 2 to 3yrs old with USB.  I will try and find my old TG585v8 router and see what stats that shows hopefully tomorrow.
As always, any ideas much appreciated.
Paul.
Community Veteran
Posts: 5,109
Thanks: 465
Fixes: 17
Registered: 10-06-2010

Re: 20CN to 21CN Speed Decrease

The downstream signal power reported as 0.0 in the web interface is common if you look at other people's stats posted in these forums - a non-zero value will be reported in the output of the "xdsl info expand=enabled" telnet command.
pmarti22
Grafter
Posts: 43
Registered: 22-11-2013

Re: 20CN to 21CN Speed Decrease

Okay.  I will have another look this evening when I get home from work.  I was using both the web interface and telnet displays at the same time, so may have misread another column, but still cannot work out why my syncs are slower with either ADSL2 or ADSL2+ activated??  At least they don't band the IP profiles anymore for ADSL when run over the 21CN, as that gave me the greatest throughput through the BT Wholesale Speed Tester.  Would the DLM band my ADSL2+ connection hence the slower speeds?  Is there an easy check to see if it has been banded without support intervention?
Many thanks
Paul.
dick:quote
pmarti22
Grafter
Posts: 43
Registered: 22-11-2013

Re: 20CN to 21CN Speed Decrease

Well I have checked the router stats using Telnet and as you can see in the attached screenshot, it still shows the download signal power as 0dBm as previously mentioned.
Any ideas anyone?  Is the router faulty?
Tried my old router and that syncs at the same speed with slightly less attenuation, although that router has always synced on the slower side compared with the TG582n.
Thanks
Community Veteran
Posts: 5,109
Thanks: 465
Fixes: 17
Registered: 10-06-2010

Re: 20CN to 21CN Speed Decrease

Then I guess the downstream power being reported as 0.0 also depends on the equipment in your exchange. I think exchanges that were upgraded to 21CN earlier report TSTC for the remote vendor, and more recent exchanges with newer equipment report the vendor as IFTN.
I don't think the power being reported as 0.0 matters, and the router is not faulty in the sense that if you got a replacement new 582n, I expect it would also report 0.0 for the power.
It may be worth trying to get a bits/tone or SNR/tone graph with some software like RouterStats or dslstats. I suppose it's possible that there's some noise affecting only the higher (1-2 MHz) ADSL2+ frequencies, which is preventing you from getting up to 9-10Mbit on ADSL2+, and you would not have known it was there until you switched to ADSL2+.
pmarti22
Grafter
Posts: 43
Registered: 22-11-2013

Re: 20CN to 21CN Speed Decrease

Thanks.  I started the DSLstats yesterday and have attached the traces that I currently have.  Also as previously mentioned, my Plusnet profile does not correlate to my actual throughput or sync speeds either using the https://portal.plus.net/my.html?action=data_transfer_speed.  This it seems is dated 11th November and has not been updated since my changeover to ADSL2+.  Can this be bumped up please?
Let me know what you think of the stats, as I can only work out the basics from these.  SNR seems quite stable, one very small blip with no loss of sync.
Phone exchange:
TAKELEY
Estimated line speed:
2.5Mb (This may vary between 1.5Mb and 5Mb) - Checked on 2013-11-11 17:08:33
Current line speed:
5.6 Mb
My shielded router RJ11 phone cable made no difference to the sync speed or attenuation levels and has always resync'd to basically the same speed each time.  Can a line test be carried out and/or line reset please to see if I have been banded by the DLM for some reason? 
Many thanks
Paul.
pmarti22
Grafter
Posts: 43
Registered: 22-11-2013

Re: 20CN to 21CN Speed Decrease

Fault raised under ref 78696752.
Having read quite a few of the forum threads now, for my attenuation, SNR and stats, I am definitely syncing under speed at 6.8Mbps.  Whilst you cannot know the full picture of other installations, most threads show that 8.5 to 9.5Mbps is the norm for such stats.
Support staff, now over to you.

Thanks