Incorrect. A 3db margin would lead to a higher sync rate, just as it would on other xDSL products.

What you're confused by is those on a 40/10 or 80/20 service that have a max attainable considerably higher than their capped rate, will have an higher SNR margin due to the fact the line is "capped" no where near its maximum potential.

In reply to a post by lee111s:

Incorrect. A 3db margin would lead to a higher sync rate, just as it would on other xDSL products.

Only on ADSL2/ADSL2+ but not on FTTC.

Why would a lower margin not lead to an increase in sync? If the line isn't in cap then a lower margin should correlate to a higher sync.

I can see my parents FTTC line stats as following:

Attainable Rate (Kbps) 41587 19200
Rate (Kbps) 42766 18767
SNR 6.1 6.2

________________________________________

Attainable Rate (Kbps) 54233 19766
Rate (Kbps) 55923 19133
SNR 7.2 6.7

Riddle me this.

Why when a customer is NOT on their max product sync speed (40meg or 80meg downstream) due to a fault or external interference, would an SNR of 9db give a LOWER speed than when the SNR of the same line is 6db?

Why would reducing the SNR to 3db not result in a speed increase.

If you have some documentation that shows VDSL2 reacts the opposite to other xDSL technologies with regards to SNR margins, then I'd be very interested to read it.

In reply to a post by adslmax:

I can see my parents FTTC line stats as following:

Attainable Rate (Kbps) 41587 19200
Rate (Kbps) 42766 18767
SNR 6.1 6.2

________________________________________

Attainable Rate (Kbps) 54233 19766
Rate (Kbps) 55923 19133
SNR 7.2 6.7

There are other factors aside from the SNR margin that affect the sync speed.

I'd like to see the documentation that shows an INCREASE in SNR margin leads to a higher sync rate. Not one example with no back up evidence. Actual documentation that explains this in detail and why it is so.

Edited by deleted (Fri 15-Apr-16 10:12:15)

By the way Openreach will not allow SNR 3dB on FTTC as there is no option for this from any isp's.

Only on ADSL2/ADSL2+ can get SNR target 3dB via BT Wholesale

In reply to a post by adslmax:

By the way Openreach will not allow SNR 3dB on FTTC as there is no option for this from any isp's.

Only on ADSL2/ADSL2+ can get SNR target 3dB via BT Wholesale

Openreach are currently trialling a 3db noise margin. Pleas ensure you know what you're talking about before spouting.

In reply to a post by lee111s:

There are other factors aside from the SNR margin that affect the sync speed.

I'd like to see the documentation that shows an INCREASE in SNR margin leads to a higher sync rate. Not one example with no back up evidence. Actual documentation that explains this in detail and why it is so.

Here is my FTTC line stats but I don't know if my downstream SNR of 13.7dB are good or bad?

Downstream Upstream
Line Coding (Trellis) On On
SNR Margin (dB) 13.7 16.0
Attenuation (dB) 11.1 0.0
Output Power (dBm) 12.5 -0.9
Attainable Rate (Kbps) 106691 36183
Rate (Kbps) 79999 19999

In reply to a post by lee111s:

Openreach are currently trialling a 3db noise margin. Pleas ensure you know what you're talking about before spouting.

Where did u get this information from? I cannot find it.