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Low SNR

XenoGuy
Grafter
Posts: 77
Registered: 27-02-2014

Low SNR

Ever since I was put on interleaving my d/l SNR is way too low... Plusnet said I'm on a 6 profile, but it instantly goes to ~3db..
Had a replacement router, still same, and I'm not sure why..... It's semi-stable but I get resyncs randomly, even get PPPoA drops too.
Here are my stats:
Quote
Uptime: 0 days, 1:32:55
DSL Type: ITU-T G.992.5
Bandwidth (Up/Down) [kbps/kbps]: 888 / 13,887
Data Transferred (Sent/Received) [MB/MB]: 9.00 / 27.67
Output Power (Up/Down) [dBm]: 11.9 / 0.0
Line Attenuation (Up/Down) [dB]: 14.6 / 29.5
SN Margin (Up/Down) [dB]: 11.1 / 3.1
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): 174 / 0
FEC Errors (Up/Down): 20 / 124,792
CRC Errors (Up/Down): 13 / 5,843
HEC Errors (Up/Down): 28 / 33,301

Am I going mad? I'm sure I had a ~22db up / ~6db down when I  wasn't on interleaving, which is meant to be more stable having it on..
47 REPLIES
Plusnet Help Team
Plusnet Help Team
Posts: 12,859
Thanks: 113
Fixes: 36
Registered: 27-04-2007

Re: Low SNR

Hi there,
I'm not sure the issue is directly related to interleaving so I've submitted an reset to get the downstream SNR back to 6db.
Let me know if you don't see any difference to this over the next 24 hours.
If this post resolved your issue please click the 'This fixed my problem' button
 Adam Walker
 Plusnet Help Team
XenoGuy
Grafter
Posts: 77
Registered: 27-02-2014

Re: Low SNR

Indeed it has gone back to 6db.... I assume the ~2pm dropout yesterday was caused by this reset? It seems stable so far.
Plusnet Help Team
Plusnet Help Team
Posts: 12,859
Thanks: 113
Fixes: 36
Registered: 27-04-2007

Re: Low SNR

Quote
I assume the ~2pm dropout yesterday was caused by this reset?

Yes, that would have been the line resyncing at the new parameters.
If this post resolved your issue please click the 'This fixed my problem' button
 Adam Walker
 Plusnet Help Team
XenoGuy
Grafter
Posts: 77
Registered: 27-02-2014

Re: Low SNR

It's back at 3.n after a drop.... What sort of line test do ISP's do, is it a basic test, in that, will it detect any major faults or do we need OR to do a rigorous test? I'm concerned if we book OR and there's no fault, I'll be charged the extortionate amount.
XenoGuy
Grafter
Posts: 77
Registered: 27-02-2014

faults.plus.net

Is there something wrong with it?
I was in the middle of it when it decided to:

Now it states this all the time
Plusnet Staff
Plusnet Staff
Posts: 17,641
Thanks: 535
Fixes: 159
Registered: 05-04-2007

Re: faults.plus.net

I'm getting the same from here on your account, the good news is that the fault ticket has dropped out for more investigation from our team here anyway so we'll pick this up and see what's going on.
If this post resolved your issue please click the 'This fixed my problem' button
 Chris Parr
 Plusnet Staff
XenoGuy
Grafter
Posts: 77
Registered: 27-02-2014

Re: faults.plus.net

Thanks, I really need my line checking...... I called this morning, explained I'm on a 6db snr profile but I'm always getting around 3db... which, to me, is kind of on the unstable side - but they said I've only dropped sync 3 times yesterday, and 1 this morning, and that is normal?!?...
So, something must be wrong.... Even changed filters, changed the RJ-11...... but still ~3db. Sad
Superuser
Superuser
Posts: 10,429
Thanks: 1,914
Fixes: 19
Registered: 22-08-2007

Re: faults.plus.net

Hi Peter,
Can you please gather all of the information requested here - http://community.plus.net/forum/index.php/topic,96155.0.html - so that we can see what your line is doing at the moment.  Some lines are quite happy running at 3dB - mine does all of the time and it thus gives me a bit more speed.
Kevin
XenoGuy
Grafter
Posts: 77
Registered: 27-02-2014

Re: faults.plus.net

Speed is fine..... Joined Plusnet from February and up until now it has been fine (to be fair, I did use the TG585n bridged to a dd-wrt for quite a while), believe it or not, I wasn't on interleaving from the off-go. Got changed to interleaving from November (I think) because I had a lot of PPPoA drops (god knows what that has to to with interleaving/fast path, but there you go), this is when the issues started.
1.
Quote
Uptime: 0 days, 10:06:23
DSL Type: ITU-T G.992.5
Bandwidth (Up/Down) [kbps/kbps]: 888 / 13,832
Data Transferred (Sent/Received) [MB/MB]: 74.58 / 948.33
Output Power (Up/Down) [dBm]: 11.6 / 0.0
Line Attenuation (Up/Down) [dB]: 14.7 / 29.5
SN Margin (Up/Down) [dB]: 13.7 / 3.7
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): 412 / 0
FEC Errors (Up/Down): 44 / 802,672
CRC Errors (Up/Down): 0 / 619
HEC Errors (Up/Down): 0 / 11,376

2.
Quote
a. Down 10.5Mbps (12.2Mbps), Up 0.47Mbps (0.83Mbps)
b. Down 11.7Mbps, Up 0.74Mbps, Ping 47.63

3.
Quote
Estimated line speed: There's no speed estimate currently held on your account.
Current line speed: 12.2 Mb

No test socket... Have 2 BT outlets but unsure which is the master, both look like LJU's - 1 is in the living room and other in the bedroom.

Superuser
Superuser
Posts: 10,429
Thanks: 1,914
Fixes: 19
Registered: 22-08-2007

Re: faults.plus.net

Peter,
Something looks not quite right here. Speed is a little slow for the reported figures. SNRM is still 3. Can you please do a restart around midday and repost the stats and I will take a look at them tomorrow.
Can you carefully remove the socket face plates. Look at the wires - colour and terminal numbers. You only need 2 & 5 connected, 3/4 can be removed if present.
Kevin
XenoGuy
Grafter
Posts: 77
Registered: 27-02-2014

Re: faults.plus.net

I still like a line test, assuming it costs nothing to them..... I'm happy with the speed, its the stability that's the main point... With my other ISP, they were LLU, so they used better equipment and so hardly had issues, the longest up time was 46 days!
If the line test is fine, then I'll proceed with alternative tweaks..... I ask for a test because a colleague said he had constant dropping, speed fluctuations and low SNR, he called BT (his isp) up and in the first instance he advised them monitoring the line for a few days, they called him back and sent an engineer out a few days later.....
Note: To my knowledge, I only have low SNR problems.....
Superuser
Superuser
Posts: 10,429
Thanks: 1,914
Fixes: 19
Registered: 22-08-2007

Re: faults.plus.net

Peter,
Low SNRM is not a fundamental issue in its own right.  SNRM is not static, it is variable due to "outside" causes.  You believe that you are on a line with a target SNRM of 6dB.  If this is correct, then there is some source of noise pushing the reported SNRM to 3dB at the time you happen to be looking.
For that reason I asked that you resynch the line during the muddle of the morning / day and immediately collected the stats.  This will confirm what is your target SNRM.
Internal wiring can have an adverse impact on a line; you may feel that things were OK before, but that does not mean that they were as good as they might have been, nor that there has no deterioration since.  I was round at a friend's house recently; they got between 9Mbps with stability and 2Mbps with no stability depending upon which phone socket they used.
Given Chris' post above, it looks as though there is a fault ticket open already.
Can you please take a look at your wiring and do that restart?
Kevin
XenoGuy
Grafter
Posts: 77
Registered: 27-02-2014

Re: faults.plus.net

I can't actually do the disconnection of wires 3 & 4 (if present) due to a physical disability, and although I'm competent with telling someone else what to do, I'm dubious. Plus, as the plate is hidden behind my big old office desk, doesn't help either Smiley
Superuser
Superuser
Posts: 10,429
Thanks: 1,914
Fixes: 19
Registered: 22-08-2007

Re: faults.plus.net

Peter,
Sorry about asking for something personally challenging.
I can understand your doubt, but the additional wires, especially in older installations, can have a marked impact on speed, noise and stability.  Newer wiring uses twisted pairs which reject high frequency noise, something highly desirable for ADSL technology but neither here nor there for voice.
The older wiring will be "solid" colours.  The newer wiring will be colour+white-trace / white+colour-trace - the colour+white wires are twisted together within the cable.  Usually the "blue pair" go to 2&5 and are the only wires required.
Kevin