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3dB SNR margin

Community Veteran
Posts: 1,595
Thanks: 62
Fixes: 2
Registered: 17-06-2007

3dB SNR margin

My line seems to be slowly moving down to the 3dB SNR margin, along with an increase in speed :

 

19:37:12, 27 Oct. (6135273.490000) PPPoE is up -​ Down Rate=43503Kbps, Up Rate=6990Kbps; SNR Margin Down=5.0dB, Up=5.9dB

 

04:59:53, 05 Nov. (6863827.290000) PPPoE is up -​ Down Rate=50079Kbps, Up Rate=7228Kbps; SNR Margin Down=3.1dB, Up=5.9dB

 

So my line has been a bit unstable over the past few days as it keeps dropping to change the speed. 

I assume that this is normal and it should all settle down once its got to what it thinks is  good.

4 REPLIES
Baldrick1
All Star
Posts: 596
Thanks: 247
Fixes: 20
Registered: 30-06-2016

Re: 3dB SNR margin

What do you mean by 'keeps dropping'? I'm guessing but I would not expect the SNR to change more than once a day. If the SNR has been wound down too far and this is causing too many disconnections then I would expect DLM to automatically start increasing it back up again. My suggestion is that you should wait for a bit too see if things improve unless of course that the instability gets to an unacceptable level.

If a PN staffer comes along he will be able to tell you precisely how many disconnections you are getting and advise.

Community Veteran
Posts: 1,595
Thanks: 62
Fixes: 2
Registered: 17-06-2007

Re: 3dB SNR margin

04:59:53, 05 Nov.	(6863827.290000) PPPoE is up -​ Down Rate=50079Kbps, Up Rate=7228Kbps; SNR Margin Down=3.1dB, Up=5.9dB
11:12:17, 04 Nov.	(6799771.750000) PPPoE is up -​ Down Rate=49919Kbps, Up Rate=7094Kbps; SNR Margin Down=3.1dB, Up=5.9dB
02:44:30, 04 Nov.	(6769304.370000) PPPoE is up -​ Down Rate=49520Kbps, Up Rate=7091Kbps; SNR Margin Down=3.2dB, Up=5.8dB
16:33:13, 03 Nov.	(6732628.230000) PPPoE is up -​ Down Rate=49363Kbps, Up Rate=7186Kbps; SNR Margin Down=3.2dB, Up=5.9dB
03:09:21, 31 Oct.	(6425199.120000) PPPoE is up -​ Down Rate=45258Kbps, Up Rate=7057Kbps; SNR Margin Down=4.3dB, Up=5.9dB
17:22:48, 28 Oct.	(6213608.700000) PPPoE is up -​ Down Rate=45258Kbps, Up Rate=7057Kbps; SNR Margin Down=4.0dB, Up=5.8dB
14:50:51, 28 Oct.	(6204491.140000) PPPoE is up -​ Down Rate=45480Kbps, Up Rate=7080Kbps; SNR Margin Down=3.9dB, Up=5.9dB
19:37:12, 27 Oct.	(6135273.490000) PPPoE is up -​ Down Rate=43503Kbps, Up Rate=6990Kbps; SNR Margin Down=5.0dB, Up=5.9dB
13:06:10, 20 Oct.	(5507016.630000) PPPoE is up -​ Down Rate=43670Kbps, Up Rate=7175Kbps; SNR Margin Down=5.0dB, Up=5.9dB
bluewhale
Rising Star
Posts: 884
Thanks: 15
Registered: 30-07-2007

Re: 3dB SNR margin

i have the same 3db profile and since i noticed it's also been dropping connection

it hasn;t stabilised over a 2 month plus period, it keeps dropping at least once a day

i'm about to have my stability profile changed so maybe that will fix it as i have a youview box and don;t want connection drops

 

i notice like mine yours is disconnecting at all times of the day, my understanding of the DLM is that it only deliberately disconnects during the night, but then not totally sure as openreach seem to be tight lipped on the FTTC DLM

 

 

i also had a profile reset back to 6db, ie as if a new line, but after a few days it's now back to the 3db level and the way the snr is bouncing about i suspect the disconnects will return

 

i'm using routerstatshub to monitor the snr

 

here is what is going on today

 

RSHub-NoiseMargin-20171106-005309.jpg

and here is a typical disconnect event before the DLM reset

RSHub-NoiseMargin-20171027-180434.jpg

 

seanius
Dabbler
Posts: 10
Registered: 06-09-2017

Re: 3dB SNR margin

This is the same problem I believe I am experiencing also.  Please see this thread.

 

 

Any advice from Plusnet to address this would be appreciated.  I would prefer line stability vs. speed.