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Sudden Increase in SNR Margin

cancunia
Rising Star
Posts: 58
Thanks: 4
Fixes: 1
Registered: ‎18-09-2019

Sudden Increase in SNR Margin

I'm still fairly new to Plusnet so am not sure if this is anything to be concerned about, advice welcome.

I've been monitoring the SNR margin via my router for the past couple of weeks after a lot of initial problems, it's been steady at around 3, and even dropped to around 2 for a while. Suddenly overnight it's gone from around 1, then up to 4 and is now showing rapid fluctuations between 4-6 since about 6am.  I've had a slight drop in linespeed, but nothing major.

 

Thanks

3 REPLIES 3
JOLO
Plusnet Alumni (retired)
Plusnet Alumni (retired)
Posts: 1,149
Fixes: 76
Registered: ‎06-08-2018

Re: Sudden Increase in SNR Margin

@cancunia,

 

I've run some checks on your connection and I don't think it's anything to particularly worry about at the moment.

 

As a rule of thumb a 3dB profile is generally considered negative as with a number of connections it can cause throughput and stability issues. The 'ideal' SNR is always suggested to be around 6-9dB as these have the least amount of interference and are considered the most stable, but as you've noticed your throughput gets decreased. Technically the lower your noise margin the faster your connection will be, but the more prone to severe errors and instability it will also be. The higher (up to a max of 18dB, though the maximum I've seen is 15dB) the lower your speed but the more stable. 

 

Your line speed currently is still above the estimates, and the line is much more stable comparative to when your connection first came live. In all honestly stability is a more important factor, especially on a long ADSL line like yours, so I'd suggest also monitoring this too - there are a number of quality monitors you can use online that persistently monitor your connection for a pro-longed period of time. 

If this post resolved your issue please click the 'This fixed my problem' button
 Joe
 Plusnet Help Team
cancunia
Rising Star
Posts: 58
Thanks: 4
Fixes: 1
Registered: ‎18-09-2019

Re: Sudden Increase in SNR Margin

Thanks for looking into this for me Joe. My main concern was that the SNR margin has suddenly just about doubled and that trouble was on the horizon. I'll monitor things and report back if the noise margin increases or the line speed drops below current.

From looking at the router stats over the past 24 hours the line speed has been stable and the snr margin is bouncing between 4 & 6. Is this a reflection of the amount of noise on the line, or is this simply a feature of the DLM in action?

Can you post examples of the persistent quality monitors mentioned above?

 

 

JOLO
Plusnet Alumni (retired)
Plusnet Alumni (retired)
Posts: 1,149
Fixes: 76
Registered: ‎06-08-2018

Re: Sudden Increase in SNR Margin

@cancunia,

 

It's always best to double check.

 

To be honest it could be both, if I were to guess it would be that as the line has stablised (it was dropping more previously), the noise margin has stabilised too as errors will have reduced, so DLM would have settled as well.

 

Think Broadband has a number of monitoring tools available that are quite popular, your router logs will also give an indication of dropouts. We are also able to generate connection graphs from our side that show sync drops - but we don't have realtime SNR monitoring available. 

If this post resolved your issue please click the 'This fixed my problem' button
 Joe
 Plusnet Help Team