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Request to reset SNR

pnf
Grafter
Posts: 266
Registered: 07-11-2007

Request to reset SNR

On 1st June the telephone cable from the telegraph pole to my house was replaced.  The old cable was badly corroded and caused problems every time it rained or there were strong winds.
Since the cable has been replaced my line has been stable with fewer errors than ever before.  However, my SNR seems to be stuck on a 9db profile.  I have rebooted the router 4 times since 1st June (about once every 12 days) but the SNR has not gone back to its usual 6db / 3db profile.  My line is currently syncing at 10,002 kbps, which is not bad, but it used to sync at about 13000 kbps.
Would it be possible for someone at PlusNet to reset my SNR so that my line can get back to normal?  
Thanks in anticipation.

Line Stats since last reboot:
--------------------------------------
Uptime: 2 days, 23:17:24
Modulation: G.992.5 annex A
Bandwidth (Up/Down) [kbps/kbps]: 446 / 10,002
Data Transferred (Sent/Received) [MB/MB]: 40.24 / 331.42
Output Power (Up/Down) [dBm]: 12.5 / 22.5
Line Attenuation (Up/Down) [dB]: 17.5 / 33.5
SN Margin (Up/Down) [dB]: 21.0 / 11.0
Vendor ID (Local/Remote): TMMB / TSTC
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): 10 / 0
FEC Errors (Up/Down): 18,585,773 / 2,147,978
CRC Errors (Up/Down): 4,557 / 61
HEC Errors (Up/Down): 1,733 / 56

edit:  corrected typo.
13 REPLIES
Community Veteran
Posts: 38,460
Thanks: 1,028
Fixes: 62
Registered: 15-06-2007

Re: Request to reset SNR

Something still isn't right on your connection which is probably why the noise margin hasn't dropped
With an upstream noise margin of 21dB there is no way you should be seeing that many FEC errors in 3 days
Also the downstream FEC errors are a bit high for the reported noise margin although the CFC and HEC errors are OK
Are you sure that the default downstream noise margin is 9dB as from the figures you have given it looks more like 12dB
Have you tried the test socket to see if the reported errors drop significantly.
I suggest running Routerstats to see what is happening to your noise margin over time including over night - this will mean that the computer has to be left running
pnf
Grafter
Posts: 266
Registered: 07-11-2007

Re: Request to reset SNR

I have a Speedtouch 780WL router.  Those upstream errors are a feature of that router.  They are reported as that value when the router is rebooted and never really change.  The upstream error count on a day to day basis is negligible.
Yes I'm sure the SNR profile is 9db, with the very hot weather over the last few days the SNR margin has crept up somewhat.
I was connected to the test socket for a while until I was certain that the problems had been resolved.  I can assure you that my line is better than it has ever been in terms of error counts and my router used to happily sync at 11,000 to 12,000 on a 6db SNR and at 12,000 to 13,000 on a 3db profile.
Plusnet Help Team
Plusnet Help Team
Posts: 13,396
Thanks: 243
Fixes: 68
Registered: 27-04-2007

Re: Request to reset SNR

@pnf
Line tests are showing me an SNR margin of 10.6 at the moment  and a synch speed of 10mb. I'm hesitant to bring it any lower as it looks like it could cause some disconnections.
Its up to you if you want us to try that too, also I'd like to perform another line test with your router in the test socket to see if anything differs.
Adam
If this post resolved your issue please click the 'This fixed my problem' button
 Adam Walker
 Plusnet Help Team
pnf
Grafter
Posts: 266
Registered: 07-11-2007

Re: Request to reset SNR

Thanks for your help Adam. 
I'd be happy for you to carry out a line test with my router connected to the test socket.  I'd also be happy for the SNR to be set so that the line can retrain to find its stable level.
I will connect the router to the test socket and post back when I've done it.
Plusnet Help Team
Plusnet Help Team
Posts: 13,396
Thanks: 243
Fixes: 68
Registered: 27-04-2007

Re: Request to reset SNR

OK, no problem. I'll await your reply and we'll take things from there.
Adam
If this post resolved your issue please click the 'This fixed my problem' button
 Adam Walker
 Plusnet Help Team
pnf
Grafter
Posts: 266
Registered: 07-11-2007

Re: Request to reset SNR

I've now connected the router to the test socket.
pnf
Grafter
Posts: 266
Registered: 07-11-2007

Re: Request to reset SNR

Quote from: Oldjim

I suggest running Routerstats to see what is happening to your noise margin over time including over night - this will mean that the computer has to be left running

@Oldjim
Just started RouterStats.  Will post back tomorrow with more results.
Plusnet Help Team
Plusnet Help Team
Posts: 13,396
Thanks: 243
Fixes: 68
Registered: 27-04-2007

Re: Request to reset SNR

OK, I've just run another test for you and can see some difference in the stats, the SNR margin has reduced to 9.1, the synch speed has reduced a little but not by much though.
I'll give the SNR reset a try this time for you but there might be some issues beyond the master socket that you want to look at too.
Adam
If this post resolved your issue please click the 'This fixed my problem' button
 Adam Walker
 Plusnet Help Team
Community Veteran
Posts: 38,460
Thanks: 1,028
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Registered: 15-06-2007

Re: Request to reset SNR

Adam,
Sorry to jump in but can you be a bit clearer about the issues beyond the master socket
The reason for asking was that when he was connected to the normal socket he achieved a speed of 10,002kbps with a 9dB default noise margin (as per his second post) and in the test socket you say that the speed has dropped a bit with the same default noise margin
pnf
Grafter
Posts: 266
Registered: 07-11-2007

Re: Request to reset SNR

@Adam
Thanks for carrying out the reset, it has had the desired effect as can be seen in the RouterStats graph attached.  My SNR is now at 6.5db and my download sync speed is 11,614kbps which is in line with my expectations.  In due course I expect the BT systems will drop the SNR margin to 3 db and my speeds will then be between 12,000kbps and 13,000kbps just the way it used to be before I had the problem with the outside line.

Quote from: Oldjim

... The reason for asking was that when he was connected to the normal socket he achieved a speed of 10,002kbps with a 9dB default noise margin (as per his second post) and in the test socket you say that the speed has dropped a bit with the same default noise margin

@Oldjim
I get roughly the same speed, noise margin and error counts whether connected to the test socket or to the extension socket which is only 6ft from the test socket but on a different wall.  The fluctuation in sync speed is all to do with the time the router resyncs and ambient weather conditions but doesn't vary that much.  The last 4 times that I have rebooted the router the sync speed on a 9db SNR profile was somewhere between 9,800 kbps and 10,000kbps.

Plusnet Help Team
Plusnet Help Team
Posts: 13,396
Thanks: 243
Fixes: 68
Registered: 27-04-2007

Re: Request to reset SNR

No problem, the SNR is at 6.1db currently and the connection has been up for over 19 hours. Here's hoping things remain that way for you! Smiley
If this post resolved your issue please click the 'This fixed my problem' button
 Adam Walker
 Plusnet Help Team
pnf
Grafter
Posts: 266
Registered: 07-11-2007

Re: Request to reset SNR

Just thought I would post some stats following the reset (router still in test socket).  As can be seen from the two sets of figures below the upstream FEC, CRC & HEC errors have not changed since the router resynced and the number of downstream CRC & HEC errors in the 24 hour period is low.  Everything looks perfectly stable.
One other thing that I have noticed is that my upload sync speed has almost doubled to 828kbps from 446 kbps, so if it stays like that it will be an unexpected bonus!

Link Information since reset:
--------------------------------------
Uptime: 0 days, 4:19:49
Modulation: G.992.5 annex A
Bandwidth (Up/Down) [kbps/kbps]: 828 / 11,614
Data Transferred (Sent/Received) [MB/MB]: 1.15 / 2.79
Output Power (Up/Down) [dBm]: 12.5 / 23.0
Line Attenuation (Up/Down) [dB]: 17.5 / 33.5
SN Margin (Up/Down) [dB]: 8.0 / 6.5
Vendor ID (Local/Remote): TMMB / TSTC
Loss of Framing (Local/Remote): 0 / 0
Loss of Signal (Local/Remote): 1 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): 0
Error Seconds (Local/Remote): 11 / 0
FEC Errors (Up/Down): 25,656,501 / 166,413
CRC Errors (Up/Down): 6,318 / 11
HEC Errors (Up/Down): 2,427 / 9

Link Information since reset:
--------------------------------------
Uptime: 1 day, 0:00:00
Modulation: G.992.5 annex A
Bandwidth (Up/Down) [kbps/kbps]: 828 / 11,614
Data Transferred (Sent/Received) [MB/MB]: 14.77 / 89.64
Output Power (Up/Down) [dBm]: 12.5 / 23.0
Line Attenuation (Up/Down) [dB]: 17.5 / 33.5
SN Margin (Up/Down) [dB]: 8.0 / 6.5
Vendor ID (Local/Remote): TMMB / TSTC
Loss of Framing (Local/Remote): 0 / 0
Loss of Signal (Local/Remote): 1 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): 0
Error Seconds (Local/Remote): 11 / 0
FEC Errors (Up/Down): 25,656,501 / 1,091,457
CRC Errors (Up/Down): 6,318 / 69
HEC Errors (Up/Down): 2,427 / 65

Attached is a pdf file containing RouterStats graphs which shows the variation in the SNR over the 24 hour period.
Thanks Adam and Oldjim for your support.  Much appreciated!


Plusnet Help Team
Plusnet Help Team
Posts: 13,396
Thanks: 243
Fixes: 68
Registered: 27-04-2007

Re: Request to reset SNR

No problem, that's what I call a satisfied customer Smiley
If this post resolved your issue please click the 'This fixed my problem' button
 Adam Walker
 Plusnet Help Team