Instability of 21CN and ADSL2+

[#1]

I find it difficult to reconcile those upstream sync speeds with the reported noise margins. I'm still on maxDSL but 448kbps upstream sync goes with 22.0dB SNR Margin on a TG585v7 (and the same on a Netgear DG834Gv4). So is the router faulty? Hopefully trying your v6 will answer that.
I'm not convinced that monitoring with Routerstats will really show anything, but it can be made to work with the TG585v7. The instructions for setting it up are given in the Routerstats Help document, but I configured it as follows:
First select the Other router radio button, then
set URL to router stats page to http://192.168.1.254/cgi/b/dsl/dt/?be=0&l0=1&l1=0
Either enter the router login Username and Password, or if the password is blank put a tick against The router does not require a Username
Go to the Router Search Text tab and select Use Source B
Click the Get Page button
In turn find your Tx Noise, Rx Noise, Tx Sync and Rx Sync values (in any order), mark them and click the setting buttons
You should find the correct value is displayed at the bottom of the page. If this is wrong try selecting a different part of the value and select again
Once all values are set click the Graphs tab and configure those as appropriate.
Once the graphs are configured click Apply & Save then Close
Now click the Start button (green triangle) to begin monitoring
If (as I did) you find the value for Rx Noise displayed at the top of the window is actually Tx Noise closing down Routerstats then starting it again fixed this problem for me.
Hope this works for you. I find the connection settings are lost if the configuration page is opened to change anything so be prepared to reset these if it stops working.
David

[#2]

The problem described at the start of this thread sounds a bit similar to mine (details at http://community.plus.net/forum/index.php/topic,76505.0.html)
As I asked there, does anyone know why I sometimes get a negative downstream noise margin of -2db? (I can't connect when this is happening, as you might expect).
More generally, how do I find out what my target noise margin is? My router (ZyXEL P660HW-61) tells me what the margin is at the current time, but there's nowhere I can set it - unless it's buried somewhere deep in the router's command language: I couldn't find anything when I looked, but that could be down to my ignorance).
Graham

[#3]

I agree with you david.  Upstream syncs seem to be completely random, and bear no relation to the noise margins. I do think its either the router, or the Exchange equipment, but I will have to go thought the issues with testing at the test socket etc.  Will connect up the V6 later this AM, and monitor for a couple of days, see what happens. If still unstable, will unplug the Filtered faceplate and connect to master socket even though faceplate only 5months old, Its an XTE2005 from broadband buyer. Also got a high speed Rj11 cable at the same time https://www.broadbandbuyer.co.uk/Shop/ShopDetail.asp?ProductID=4408
Should I try a bod standard cable as well?
Will post back with results, from the first resync, on the V6.  Has anyone any ideas how to pull logs from the V6, rather then the limited logs it displays, only really get the last 20odd things, dosnt seem to save any longer logs unless I have to use the telnet interface. Not sure how to pull more logs from it, if indeed this is possible,

[#4]

Quote from: grahamt

As I asked there, does anyone know why I sometimes get a negative downstream noise margin of -2db? (I can't connect when this is happening, as you might expect).

Simple answer is the noise is increasing on your line but the question you really need to ask as the change in SNRM is 11dB is the cause of the noise internal or external to your house? The former you can contol/fix the latter you have no control over. Have you done any checks on your internal wirring?

[#5]

Connected 585V6.  Stats currently
Link Information

Uptime: 0 days, 0:02:13
DSL Type: G.992.5 annex A
Bandwidth (Up/Down) [kbps/kbps]: 888 / 7.681
Data Transferred (Sent/Received) [kB/kB]: 6,00 / 8,00
Output Power (Up/Down) [dBm]: 12,5 / 0,0
Line Attenuation (Up/Down) [dB]: 24,0 / 45,0
SN Margin (Up/Down) [dB]: 10,5 / 6,5
Vendor ID (Local/Remote): TMMB / 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): 0
Error Seconds (Local/Remote): 0 / 0
FEC Errors (Up/Down): 0 / 2.654
CRC Errors (Up/Down): 0 / 0
HEC Errors (Up/Down): 0 / 0
Using firmware 7.4.3.2 
Lets see how things go now......

[#6]

I've done the 'quiet line' test, and my line is quiet, although I haven't yet tried this at the time when I've had the -2db problem. I've tried plugging my router into what is nominally my master socket (my wiring is vintage 1989, BT-installed, and two lines were installed at the time, one of them now shut down) with everything else unplugged - made no difference.
Since I started the trial my downstream noise margin has usually been either 5db or 9db. But when I've had the problem the pattern is:
Problem noticed (around midnight): router is restarting 'line up' count every minute, precisely. WAN IP is 0.0.0.0. PPPoA status is 'LCP up' rather than 'Up'.  Sync is ca. 5000, SNR is -2db
Reset the ADSL line: normal WAN IP, PPPoA is 'Up'. sync is ca. 3200, SNR is 12db
Reset the line again in the morning: sync is ca. 5000, SNR is 9db.
If I do have an internal wiring problem, what would cause such a big change late at night? The TV being on? It's a long way from any phone wires.
Graham

[#7]

The ring/bell wire is a source of noise but this is normally seen throughout the day not just at night. First recommendation is to disconnect all wires in the master socket except the 2 going to terminal 2 and 5. For more information go here http://www.kitz.co.uk/adsl/socket.htm

[#8]

Thanks. My problem is that I have one of the more complicated wiring layouts. Matching up what I can remember when the wiring was installed with the Kitz info, I think I have a block terminal in the loft, then another block terminal on the landing, from which my currently-used line goes off in star fashion to four extensions, one of which is nominally the master socket (not an NTE5, though the wiring was installed in 1989, after these were introduced), and also another line goes off to a single socket. This second line used to be my computer line when we had dial-up. It's not used any more, but I bet its ring wire also affects my connection. Just to make things even more complicated, the one socket of the second line is physically shared with one of the sockets of the first line (i.e. there are two actual sockets in the one housing).
I'm not quite sure where I'd be legally allowed to cut the ring wire. I guess I would be legal in the case of all the sockets that can take a phone, but what about the block terminals? They could both be BT's property. Is there any point in disconnecting the ring wire from the sockets without disconnecting it from the block terminal(s)?
And as you say, this shouldn't be a problem only at some times of day. So I could easily try to do it, mess it up, have to call out Openreach for loads of money, and maybe still not have a better connection (although if I had to call them out I'd make sure the place was rewired optimally for ADSL2+).
I've got one person I could call on who may have the knowledge and skills I need. I'll try that before doing anything else. Thanks again.
Graham

[#9]

Well not really any better, 3 resyncs on the V6 since I set it up. Apart from the most recent, detailed below, Upstream syncs have been OK.
Link Information

Uptime: 0 days, 0:01:58
DSL Type: G.992.5 annex A
Bandwidth (Up/Down) [kbps/kbps]: 235 / 7.054
Data Transferred (Sent/Received) [kB/MB]: 344,00 / 4,79
Output Power (Up/Down) [dBm]: 11,5 / 0,0
Line Attenuation (Up/Down) [dB]: 25,0 / 45,0
SN Margin (Up/Down) [dB]: 11,0 / 6,5
Vendor ID (Local/Remote): TMMB / IFTN
I seem to keep getting these crappy low upstreams, even though the margin suggests its should be much higher.  I suppose the next step is removing faceplate and connecting via a filter into master socket. If still the same them I think a BT engineer should be called.  Any advice chaps?
Recent logs
10:14:38 (since last boot) FIREWALL event (1 of 1): deleted rules

Warning 10:14:38 (since last boot) PPP link up (Internet) [80.229.156.222]

Info 10:14:38 (since last boot) PPP CHAP Chap receive success : authentication ok

Info 10:14:38 (since last boot) PPP CHAP Receive challenge (rhost = THN-AG2)

Info 10:14:37 (since last boot) PPP CHAP Receive challenge (rhost = bras-red1.pr)

Info 10:14:22 (since last boot) xDSL linestate up (ITU-T G.992.5; downstream: 7054 kbit/s, upstream: 235 kbit/s; output Power Down: 20.0 dBm, Up: 11.5 dBm; line Attenuation Down: 45.0 dB, Up: 25.0 dB; snr Margin Down: 6.5 dB, Up: 6.0 dB)

Warning 10:14:21 (since last boot) PPP link down (Internet) [80.229.156.222]

Info 10:13:58 (since last boot) xDSL linestate down

Info 10:13:39 (since last boot) FIREWALL event (1 of 1): created rules

Info 10:13:38 (since last boot) xDSL linestate down

Info 09:54:05 (since last boot) CONFIGURATION mbus igd sync successfull

Info 09:53:49 (since last boot) CONFIGURATION mbus atomic sync successful

Info 07:50:52 (since last boot) FIREWALL event (1 of 1): deleted rules

Warning 07:50:52 (since last boot) PPP link up (Internet) [80.229.156.222]

Info 07:50:52 (since last boot) PPP CHAP Chap receive success : authentication ok

Info 07:50:52 (since last boot) PPP CHAP Receive challenge (rhost = THN-AG2)

Info 07:50:52 (since last boot) PPP CHAP Receive challenge (rhost = bras-red1.pr)

Info 07:50:51 (since last boot) xDSL linestate up (ITU-T G.992.5; downstream: 7645 kbit/s, upstream: 776 kbit/s; output Power Down: 20.5 dBm, Up: 12.5 dBm; line Attenuation Down: 44.5 dB, Up: 24.0 dB; snr Margin Down: 6.5 dB, Up: 6.5 dB)

Info 07:50:27 (since last boot) xDSL linestate down

Info 07:50:05 (since last boot) xDSL linestate down

Info 07:49:32 (since last boot) xDSL linestate up (ITU-T G.992.5; downstream: 7645 kbit/s, upstream: 707 kbit/s; output Power Down: 20.0 dBm, Up: 12.5 dBm; line Attenuation Down: 44.5 dB, Up: 24.0 dB; snr Margin Down: 6.5 dB, Up: 6.5 dB)

Warning 07:49:23 (since last boot) PPP link down (Internet) [80.229.156.222]

Info 07:49:08 (since last boot) xDSL linestate down

Info 07:48:49 (since last boot) FIREWALL event (1 of 24): created rules

Info 07:48:49 (since last boot) xDSL linestate down

Info 00:05:47 (since last boot) CONFIGURATION mbus igd sync successfull

Info 00:05:31 (since last boot) CONFIGURATION mbus atomic sync successful

Info 00:05:01 (since last boot) LOGIN User admin tried to login on [HTTP] (from 192.168.1.4)

Info 00:04:44 (since last boot) LOGIN User admin logged in on [HTTP] (from 192.168.1.4)

Info 00:03:11 (since last boot) LOGIN User Administrator logged in on [HTTP] (from 192.168.1.4)

Info 00:01:15 (since last boot) FIREWALL event (1 of 6): deleted rules

Warning 00:01:15 (since last boot) PPP link up (Internet) [80.229.156.222]

Info 00:01:14 (since last boot) PPP CHAP Chap receive success : authentication ok

Info 00:01:14 (since last boot) PPP CHAP Receive challenge (rhost = THN-AG2)

Info 00:01:14 (since last boot) PPP CHAP Receive challenge (rhost = bras-red1.pr)

Info 00:01:12 (since last boot) xDSL linestate up (ITU-T G.992.5; downstream: 7681 kbit/s, upstream: 888 kbit/s; output Power Down: 20.5 dBm, Up: 12.5 dBm; line Attenuation Down: 45.0 dB, Up: 24.0 dB; snr Margin Down: 6.0 dB, Up: 10.0 dB)

Info 00:00:48 (since last boot) xDSL linestate down

Warning 00:00:25 (since last boot) DHCS server up

Info 00:00:25 (since last boot) FIREWALL event (1 of 1): deleted rules

Info 00:00:25 (since last boot) FIREWALL level changed to Disabled.


Pick a task...
Clear the event log
Also odd that the downstream seems to be higher, and more consistent than with the V7.

[#10]

Since you've tried another router and got the same problem I think your assumption is correct - you need to try connecting to the test socket via a microfilter. If that shows the same disconnections I think it is odds on that there is an intermittent connection fault external to your property.
To answer an earlier question, you can get more log entries from the Speedtouch/TG585v6/v7 through the telnet interface.
In a command-prompt window type telnet 192.168.1.254, then enter the router's username (and password if it has one)
To display the log type systemlog show
Follow the instructions in the quote for copying information displayed in the command-prompt window to the clipboard (for later pasting elsewhere)

Quote from: spraxyt

Right-click in the command-prompt window then click Select All (to do what it says on the tin), or click Mark, point to the left-hand margin of the line where copying is to start, press and hold the left mouse button while dragging the pointer to the right-hand margin of the last line to be copied. The area selected should display as black text on a white background. Right-click in this area; the text will revert to white on black with the copied text on the clipboard. Paste this into Notepad, or as required.

David

[#11]

Thanks David, really appreciate your help and advice here. Will connect to the test socket tomorrow, to get a decent SNR. Will post back with results.  Have an open ticket with the CSC as well
Cheers
Chris
Recent Router Logs
{admin}=>systemlog show
<4> SysUpTime: 00:00:01 KERNEL Cold restart
<24> SysUpTime: 00:00:02 [CWMP: 0:00:02.410] setting cwmp defaults
<6> SysUpTime: 00:00:02 WIRELESS interface turned on.
<85> SysUpTime: 00:00:14 FIREWALL event (1 of 1): created rules
<85> SysUpTime: 00:00:14 FIREWALL event (1 of 1): modified rules
<85> SysUpTime: 00:00:25 FIREWALL level changed to Disabled.
<85> SysUpTime: 00:00:25 FIREWALL event (1 of 1): deleted rules
<148> SysUpTime: 00:00:25 DHCS server up
<173> SysUpTime: 00:00:48 xDSL linestate down
<173> SysUpTime: 00:01:12 xDSL linestate up (ITU-T G.992.5; downstream: 7681 kbi
t/s, upstream: 888 kbit/s; output Power Down: 20.5 dBm, Up: 12.5 dBm; line Atten
uation Down: 45.0 dB, Up: 24.0 dB; snr Margin Down: 6.0 dB, Up: 10.0 dB)
<39> SysUpTime: 00:01:14 PPP CHAP Receive challenge (rhost = bras-red1.pr)
<39> SysUpTime: 00:01:14 PPP CHAP Receive challenge (rhost = THN-AG2)
<38> SysUpTime: 00:01:14 PPP CHAP Chap receive success : authentication ok
<132> SysUpTime: 00:01:15 PPP link up (Internet) [80.229.156.222]
<85> SysUpTime: 00:01:15 FIREWALL event (1 of 6): deleted rules
<37> SysUpTime: 00:03:11 LOGIN User Administrator logged in on [HTTP] (from 192.
168.1.4)
<37> SysUpTime: 00:04:44 LOGIN User admin logged in on [HTTP] (from 192.168.1.4)
<37> SysUpTime: 00:05:01 LOGIN User admin tried to login on [HTTP] (from 192.168
.1.4)
<14> SysUpTime: 00:05:31 CONFIGURATION mbus atomic sync successful
<14> SysUpTime: 00:05:47 CONFIGURATION mbus igd sync successfull
<173> SysUpTime: 07:48:49 xDSL linestate down
<85> SysUpTime: 07:48:49 FIREWALL event (1 of 24): created rules
<173> SysUpTime: 07:49:08 xDSL linestate down
<132> SysUpTime: 07:49:23 PPP link down (Internet) [80.229.156.222]
<173> SysUpTime: 07:49:32 xDSL linestate up (ITU-T G.992.5; downstream: 7645 kbi
t/s, upstream: 707 kbit/s; output Power Down: 20.0 dBm, Up: 12.5 dBm; line Atten
uation Down: 44.5 dB, Up: 24.0 dB; snr Margin Down: 6.5 dB, Up: 6.5 dB)
<173> SysUpTime: 07:50:05 xDSL linestate down
<173> SysUpTime: 07:50:27 xDSL linestate down
<173> SysUpTime: 07:50:51 xDSL linestate up (ITU-T G.992.5; downstream: 7645 kbi
t/s, upstream: 776 kbit/s; output Power Down: 20.5 dBm, Up: 12.5 dBm; line Atten
uation Down: 44.5 dB, Up: 24.0 dB; snr Margin Down: 6.5 dB, Up: 6.5 dB)
<39> SysUpTime: 07:50:52 PPP CHAP Receive challenge (rhost = bras-red1.pr)
<39> SysUpTime: 07:50:52 PPP CHAP Receive challenge (rhost = THN-AG2)
<38> SysUpTime: 07:50:52 PPP CHAP Chap receive success : authentication ok
<132> SysUpTime: 07:50:52 PPP link up (Internet) [80.229.156.222]
<85> SysUpTime: 07:50:52 FIREWALL event (1 of 1): deleted rules
<14> SysUpTime: 09:53:49 CONFIGURATION mbus atomic sync successful
<14> SysUpTime: 09:54:05 CONFIGURATION mbus igd sync successfull
<173> SysUpTime: 10:13:38 xDSL linestate down
<85> SysUpTime: 10:13:39 FIREWALL event (1 of 1): created rules
<173> SysUpTime: 10:13:58 xDSL linestate down
<132> SysUpTime: 10:14:21 PPP link down (Internet) [80.229.156.222]
<173> SysUpTime: 10:14:22 xDSL linestate up (ITU-T G.992.5; downstream: 7054 kbi
t/s, upstream: 235 kbit/s; output Power Down: 20.0 dBm, Up: 11.5 dBm; line Atten
uation Down: 45.0 dB, Up: 25.0 dB; snr Margin Down: 6.5 dB, Up: 6.0 dB)
<39> SysUpTime: 10:14:37 PPP CHAP Receive challenge (rhost = bras-red1.pr)
<39> SysUpTime: 10:14:38 PPP CHAP Receive challenge (rhost = THN-AG2)
<38> SysUpTime: 10:14:38 PPP CHAP Chap receive success : authentication ok
<132> SysUpTime: 10:14:38 PPP link up (Internet) [80.229.156.222]
<85> SysUpTime: 10:14:38 FIREWALL event (1 of 1): deleted rules
<173> SysUpTime: 01 day 05:16:58 xDSL linestate down
<85> SysUpTime: 01 day 05:16:58 FIREWALL event (1 of 1): created rules
<173> SysUpTime: 01 day 05:17:21 xDSL linestate down
<173> SysUpTime: 01 day 05:17:45 xDSL linestate up (ITU-T G.992.5; downstream: 7
022 kbit/s, upstream: 312 kbit/s; output Power Down: 20.0 dBm, Up: 12.5 dBm; lin
e Attenuation Down: 45.5 dB, Up: 25.0 dB; snr Margin Down: 6.0 dB, Up: 6.0 dB)
<85> SysUpTime: 01 day 05:17:45 FIREWALL event (1 of 1): deleted rules
<132> SysUpTime: 01 day 05:17:46 PPP link down (Internet) [80.229.156.222]
<173> SysUpTime: 01 day 05:18:03 xDSL linestate down
<173> SysUpTime: 01 day 05:18:26 xDSL linestate down
<173> SysUpTime: 01 day 05:18:50 xDSL linestate up (ITU-T G.992.5; downstream: 7
642 kbit/s, upstream: 880 kbit/s; output Power Down: 20.5 dBm, Up: 12.5 dBm; lin
e Attenuation Down: 44.5 dB, Up: 24.0 dB; snr Margin Down: 6.0 dB, Up: 6.5 dB)
<39> SysUpTime: 01 day 05:18:52 PPP CHAP Receive challenge (rhost = bras-red1.pr
)
<39> SysUpTime: 01 day 05:18:52 PPP CHAP Receive challenge (rhost = THN-AG2)
<38> SysUpTime: 01 day 05:18:52 PPP CHAP Chap receive success : authentication o
k
<132> SysUpTime: 01 day 05:18:53 PPP link up (Internet) [80.229.156.222]
<85> SysUpTime: 01 day 05:18:53 FIREWALL event (1 of 1): deleted rules
<173> SysUpTime: 01 day 05:26:58 xDSL linestate down
<85> SysUpTime: 01 day 05:26:58 FIREWALL event (1 of 2): created rules
<173> SysUpTime: 01 day 05:27:17 xDSL linestate down
<173> SysUpTime: 01 day 05:27:41 xDSL linestate up (ITU-T G.992.5; downstream: 7
645 kbit/s, upstream: 888 kbit/s; output Power Down: 20.5 dBm, Up: 13.0 dBm; lin
e Attenuation Down: 44.5 dB, Up: 24.0 dB; snr Margin Down: 6.5 dB, Up: 8.0 dB)
<85> SysUpTime: 01 day 05:27:41 FIREWALL event (1 of 1): deleted rules
<132> SysUpTime: 01 day 05:27:43 PPP link down (Internet) [80.229.156.222]
<39> SysUpTime: 01 day 05:27:59 PPP CHAP Receive challenge (rhost = bras-red1.pr
)
<39> SysUpTime: 01 day 05:27:59 PPP CHAP Receive challenge (rhost = THN-AG2)
<38> SysUpTime: 01 day 05:28:00 PPP CHAP Chap receive success : authentication o
k
<132> SysUpTime: 01 day 05:28:00 PPP link up (Internet) [80.229.156.222]
<37> SysUpTime: 01 day 06:42:09 LOGIN User admin logged in on [HTTP] (from 192.1
68.1.64)
<37> SysUpTime: 01 day 07:43:08 LOGIN User logged in on TELNET (192.168.1.64)
{admin}=>

[#12]

Quote from: penfold

<173> SysUpTime: 10:14:22 xDSL linestate up (ITU-T G.992.5; downstream: 7054 kbi t/s, upstream: 235 kbit/s; output Power Down: 20.0 dBm, Up: 11.5 dBm; line Atten uation Down: 45.0 dB, Up: 25.0 dB; snr Margin Down: 6.5 dB, Up: 6.0 dB)

The full history in the log looks normal to me with the exception of the disconnections which should not be happening. My feeling is that these are being caused by short bursts of lower frequency noise (possibly audible on a quiet line test if you were quick enough). On the re-sync instance I've highlighted one can speculate that the noise was still present on completion since the "extremely poor" upstream sync speed and "normal" SNR Margin value are incompatible in my view. Downstream sync speed doesn't appear to have been affected.
Definitely try the test socket tomorrow I reckon.
David

[#13]

Quote

My feeling is that these are being caused by short bursts of lower frequency noise

Would these bursts of noise be external to my property then??? and what could be causing them.  I presume they are only showing up now, due to the different frequencies in use on 21CN/ADSL2+...  As said, will try the test socket tomorrow, and if still the same, then it must be an external source, and I can be confident I will not be charged for an engineer vist. Will also try 2 microfilters as well, to be absolutely sure. I must admit though the 585V6 appears to be more stable then the TG585V7.
Cheers
Chris

[#14]

Odd thing just happened.  Just had a phone call, as I was using internet. Appeared to lose sync at this point. And then again when phone put down, tried to use internet, and connection was again down.  May be a complete coincidence.  Wife said she heard no hissing/static etc on line.  Have tried quiet line test a few times recently, and apart from a very quiet hiss type noise, which I presume is background noise, there is no other cracking etc.  Rang the phone from my mobile, and answered it, no resync and no noise.

[#15]

Quote from: penfold

Would these bursts of noise be external to my property then??? and what could be causing them.

I don't think one can be absolutely sure that they are external, just try to get the balance of probability to favour that. One possibility is solenoid operated relays/starters/fridge motor being slow to operate, sparking and causing RF noise while they are doing it. Your good quality RJ11 cable should help to eliminate problems from such noise. Separately trying another RJ11 cable would help to eliminate a cable fault. And your suggestion of test socket with two different microfilters reduces the chances of a filter problem.

Quote

I presume they are only showing up now, due to the different frequencies in use on 21CN/ADSL2+...

Well yes and no or perhaps maybe
ADSL2+ extends the upper frequency band from 1.1MHz to 2.2MHz, but no problem is apparent up there. Upstream transmissions use frequencies between 25.875 and 138kHz, and because, for the trial, the upstream speed is no longer capped this frequency range has to work harder. It is possible a fault condition on maxDSL could have been masked by the 448kbps cap, but it seems unlikely.
I think moving to 21CN requires the cabling in the exchange to be moved and that is a likely source of the problem. However the problem could be one that would have happened anyway, manhole flooded and dodgy joint causing transient noise. I think dropping the connection when the telephone rings/gets answered is likely to be a joint problem - but I'm not sure of the significance of it dropping again when the receiver is replaced. I believe answering the phone can clean the joint so it doesn't happen next time, but it comes back later as the joint deteriorates again.
Lots of ifs/buts/maybes there - hope it helps.
David