Low VDSL Sync Speeds

Forums › Spark New Zealand (including Skinny and BigPipe) › Low VDSL Sync Speeds

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shakti

14 posts

Geek

#1126469 11-Sep-2014 12:43

Just thought I'd post a little update for the sake of anyone interested in knowing what happened. 10 days past and my VDSL sync speeds were sitting at about 15.2 down and 2.6 up. I felt the extra $$ didn't really give me the increase in value that I was expecting so I requested to be switched back to ADSL. I was switched back today and after a few cheeky SNR tweaks on my DGND3700 v1 I managed to get the following sync speeds (18.9 down, 1 up). Been up for 6 hours or so now and no disconnections:

adsl: ADSL driver and PHY status

Status: Showtime

Last Retrain Reason: 0

Last initialization procedure status: 0

Max: Upstream rate = 0 Kbps, Downstream rate = 14896 Kbps

Bearer: 0, Upstream rate = 1080 Kbps, Downstream rate = 18859 Kbps

Link Power State: L0

Mode: ADSL2+

TPS-TC: ATM Mode

Trellis: U:ON /D:ON

Line Status: No Defect

Training Status: Showtime

Down Up

SNR (dB): 1.1 12.0

Attn(dB): 19.0 7.3

Pwr(dBm): 20.1 12.6

ADSL2 framing

Bearer 0

MSGc: 63 9

B: 110 135

M: 1 1

T: 5 1

R: 14 0

S: 0.1880 4.0000

L: 5319 272

D: 192 1

Counters

Bearer 0

SF: 0 0

SFErr: 0 0

RS: 0 0

RSCorr: 0 0

RSUnCorr: 0 0

Bearer 0

HEC: 0 0

OCD: 0 0

LCD: 0 0

Total Cells: 0 0

Data Cells: 0 0

Drop Cells: 0

Bit Errors: 0 0

ES: 0 0

SES: 0 0

UAS: 30 30

AS: 1

Bearer 0

INP: 2.00 0.00

INPRein: 0.00 0.00

delay: 9 1

PER: 16.21 15.00

OR: 34.04 8.00

Bitswap: 0/0 0/0

Coil

6614 posts

Uber Geek
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#1126472 11-Sep-2014 12:47

SNR (dB):	 1.1		 12.0


1dB SNR, Wait till peak time and observe the frequent drops.

hio77

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Lizard Networks

#1126485 11-Sep-2014 13:00

TimA:

SNR (dB):	 1.1		 12.0


1dB SNR, Wait till peak time and observe the frequent drops.

Brave.

Very brave to be dropping that low..

atlest with adsl, you dont have a DLM profile to shaft by doing it... but 1dB is just that little bit tooooo low.....

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Any comments made are personal opinion and do not reflect directly on the position my current or past employers may have.

shakti

14 posts

Geek

#1126488 11-Sep-2014 13:03

Worst case scenario I'll bump it up until I reach stability. #yolo

hio77

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#1126492 11-Sep-2014 13:07

i wouldnt even relate #yolo to this at all.

getting that close to the noise floor is bad for stability for your line, not to mention is likely to affect neighbouring lines with the excessive noise.

#include <std_disclaimer>

Any comments made are personal opinion and do not reflect directly on the position my current or past employers may have.

shakti

14 posts

Geek

#1126548 11-Sep-2014 14:14

hio77: i wouldnt even relate #yolo to this at all.

getting that close to the noise floor is bad for stability for your line, not to mention is likely to affect neighbouring lines with the excessive noise.

What would you say is a 'safe' target value? 3 dB?

hio77

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#1126550 11-Sep-2014 14:20

shakti:
hio77: i wouldnt even relate #yolo to this at all.

getting that close to the noise floor is bad for stability for your line, not to mention is likely to affect neighbouring lines with the excessive noise.

What would you say is a 'safe' target value? 3 dB?

safe is a pretty well contested point, and so everyone will give you a different response.

below about 4dB is stepping into danger point regardless of how good your line is.

remember to consider what increasing your noise does in terms of errors, you may have reached a point where real world performance your actually doing worse due to CRCs and retransmitted packets due to packet loss from those errors.

i personally run a modest -2dB tweak on my line, so down to 10dB. Due to the way the crosstalk and such comes and goes in my area, this lands me as low as 8dB once my line settles down, averaging 9dB.

You need to remember while you may train at X snr, the noise on your line will move it around a tad, and when that hits zero... your pretty well buggered.

#include <std_disclaimer>

Any comments made are personal opinion and do not reflect directly on the position my current or past employers may have.

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dcole13

534 posts

Ultimate Geek

#1126593 11-Sep-2014 14:58

You could bomb your neibourhood so no one else is on the cabinet, but then the cabinet or your house wouldn't exist.

Home ADSL: School:

shakti

14 posts

Geek

#1126595 11-Sep-2014 15:08

hio77:
shakti:
hio77: i wouldnt even relate #yolo to this at all.

getting that close to the noise floor is bad for stability for your line, not to mention is likely to affect neighbouring lines with the excessive noise.

What would you say is a 'safe' target value? 3 dB?

safe is a pretty well contested point, and so everyone will give you a different response.

below about 4dB is stepping into danger point regardless of how good your line is.

remember to consider what increasing your noise does in terms of errors, you may have reached a point where real world performance your actually doing worse due to CRCs and retransmitted packets due to packet loss from those errors.

i personally run a modest -2dB tweak on my line, so down to 10dB. Due to the way the crosstalk and such comes and goes in my area, this lands me as low as 8dB once my line settles down, averaging 9dB.

You need to remember while you may train at X snr, the noise on your line will move it around a tad, and when that hits zero... your pretty well buggered.

Thanks for the tips man, appreciate it. I'm pretty noob to all this - kinda just being cheeky with the SNR tweaks. I may start from -2 dB and work my way to a stable line from there.

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