Ah ok, that makes more sense on the SNR.

What would cause the capped SYNC speed profile at the DSLAM? the high SNR?

How does one resolve this? i mean, what would you say to BT? if they know i know my SNR, and attainable speeds etc, wont they figure i have changed my Router?

The SNR is high because the SYNC speed is capped at the DLSAM. It would have happened automatically as a result of errors on the line, or a succession of disconnections. Your ISP can request this be re-trained or the cap removed, but ensure you don't have any underlying issue still as the same thing will just re-occur.

James

tried the snr trick, didnt work, i have a poor line from the cab

http://img708.imageshack.us/img708/4258/rasstats.jpg

In reply to a post by nelix01:

VDSL Port Details Upstream Downstream
Attainable Net Data Rate: 15760 kbps 47232 kbps
Actual Aggregate Tx Power: - 23.1 dBm 10.4 dBm
============================================================================
VDSL Band Status U0 U1 U2 U3 D1 D2 D3
Line Attenuation(dB): 2.7 8.9 N/A N/A 5.0 10.8 N/A
Signal Attenuation(dB): 0.0 7.9 N/A N/A 5.0 10.8 N/A
SNR Margin(dB): 22.0 21.7 N/A N/A 11.1 10.9 N/A
TX Power(dBm): -33.4 -23.5 N/A N/A 9.5 2.9 N/A

Almost exactly the same figures as my line (estimate was 32.7Mbps/7.5Mbps - ish)

VDSL Port Details Upstream Downstream
Attainable Net Data Rate: 17531 kbps 47156 kbps
Actual Aggregate Tx Power: - 16.2 dBm 10.3 dBm
============================================================================
VDSL Band Status U0 U1 U2 U3 D1 D2 D3
Line Attenuation(dB): 3.6 16.0 N/A N/A 8.8 19.8 N/A

Signal Attenuation(dB): 0.0 15.0 N/A N/A 8.8 19.8 N/A

SNR Margin(dB): 22.0 21.9 N/A N/A 11.0 10.9 N/A

TX Power(dBm): -28.6 -16.5 N/A N/A 9.5 2.6 N/A

Oddly, though, your attenuation seems to be just over half mine, yet the attainable rates are the same and both our lines are operating with almost exactly the same SNR Margin for a 39999kbps sync (indicating they've both got similar capacity for the same extra speed, despite my line attenuation being much higher).

you have a excellent line there, but I see you are 100ish meters from the cab.

mine is between 350 and 400 meters.

Aye, the FTTC CAB is just at the entrance to the housing development. Much better than being over 8km by road from the exchange on ADSL and just about getting 1Mbps!!!!

Edited by nelix01 (Fri 16-Sep-11 15:18:10)

Here are my stats, i'm not sure of line length suspect around 300m, saw max attainable was over 53000 kbps this afternoon.



# xdslcmd info --pbParams
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Max: Upstream rate = 19114 Kbps, Downstream rate = 52212 Kbps
Path: 0, Upstream rate = 9995 Kbps, Downstream rate = 39999 Kbps

Discovery Phase (Initial) Band Plan
US: (0,95) (696,1183)
DS: (32,687) (1192,1627)
Medley Phase (Final) Band Plan
US: (0,95) (696,1183)
DS: (32,687) (1192,1627)
VDSL Port Details Upstream Downstream
Attainable Net Data Rate: 19114 kbps 52212 kbps
Actual Aggregate Tx Power: - 5.4 dBm 10.2 dBm
============================================================================
VDSL Band Status U0 U1 U2 U3 D1 D2 D3
Line Attenuation(dB): 5.9 26.7 N/A N/A 13.5 33.4 N/A
Signal Attenuation(dB): 7.9 25.9 N/A N/A 13.5 33.4 N/A
SNR Margin(dB): 22.0 21.9 N/A N/A 16.4 16.1 N/A
TX Power(dBm): -18.4 -5.7 N/A N/A 9.4 2.7 N/A

a bit better than the 2meg i was struggling to get with Sky LLU before

here is link to my stats this morning

http://img600.imageshack.us/img600/9504/btvdsl.jpg

Edited by deleted (Sat 17-Sep-11 11:23:07)

here's my latest:

xdslcmd info --pbParams
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Max: Upstream rate = 16807 Kbps, Downstream rate = 47104 Kbps
Path: 0, Upstream rate = 9995 Kbps, Downstream rate = 39999 Kbps

Discovery Phase (Initial) Band Plan
US: (0,95) (696,1183)
DS: (32,687) (1192,1627)
Medley Phase (Final) Band Plan
US: (0,95) (696,1183)
DS: (32,687) (1192,1627)
VDSL Port Details Upstream Downstream
Attainable Net Data Rate: 16807 kbps 47104 kbps
Actual Aggregate Tx Power: - 23.4 dBm 10.4 dBm
============================================================================
VDSL Band Status U0 U1 U2 U3 D1 D2 D3
Line Attenuation(dB): 2.7 8.9 N/A N/A 5.0 10.8 N/A
Signal Attenuation(dB): 0.0 8.0 N/A N/A 5.0 10.8 N/A
SNR Margin(dB): 20.6 20.5 N/A N/A 11.1 11.1 N/A
TX Power(dBm): -33.5 -23.7 N/A N/A 9.6 2.7 N/A

In reply to a post by griff_90:

As for there potentially being a problem what do you make of this -

http://img.photobucket.com/albums/v427/griff_90/0b5a...

Bob seems to be on the mark there.
If your attenuation is, indeed, 10dB (mine's 8.8dB for D1 and 19.8db for D2 - according to my modem) there must be something wrong.

My figures are

VDSL Port Details Upstream Downstream
Attainable Net Data Rate: 17475 kbps 47156 kbps
Actual Aggregate Tx Power: - 16.1 dBm 10.3 dBm
============================================================================
VDSL Band Status U0 U1 U2 U3 D1 D2 D3
Line Attenuation(dB): 3.6 16.0 N/A N/A 8.8 19.8 N/A

Signal Attenuation(dB): 0.0 14.9 N/A N/A 8.8 19.8 N/A

SNR Margin(dB): 21.8 21.8 N/A N/A 10.7 11.4 N/A

TX Power(dBm): -28.6 -16.5 N/A N/A 9.5 2.6 N/A

Your line (even assuming BT's 10dB figure was taken from the D1 figure and isn't an average across D1 and the tones used in D2) should be able to sync at maximum speed.

Your error stats aren't encouraging either.
Mine are

Line rate (kbit/s) 39999 9995
CRC errors 0 0
FEC errors 2850 177
HEC errors 6459 0

This is for a connected time of 190,000 seconds (basically since Friday lunchtime).
Either my zero CRC error count is a glitch (unlikely, given the fairly low FEC count) or your line is suffering from a fair bit of noise).

......Or the 10dB wasn't an accurate measurement in the first place.