How to Increase VDSL Upstream Power Level

Scott Pettit · ‎10-03-2013

We've got a customer with an 887VA who is on VDSL2 and is experiencing very poor upstream sync rates. Downstream sync rate is good.

Looking at the modem stats the upstream power level looks really low, only 3dBm.

Are there some commands I can insert under the controller configuration to force the power level higher? We used to be able to do this on the 877's with ADSL.

(config-controller)#?

Controller configuration commands:

bitswap Bit swap

default Set a command to its defaults

description Controller specific description

diagnostics Diagnostics DELT

exit Exit from controller configuration mode

firmware Active firmware file name

help Description of the interactive help system

modem vdsl modem configuration

no Negate a command or set its defaults

operating Configure auto or specific VDSL operating mode

shutdown Shutdown vdsl controller

sra Seemless Rate Adaption

sync xDSL sync preferences

training Dsl firmware training log

Here are the line stats:

Attainable Rate: 18272 kbits/s 560 kbits/s

Actual Power: 12.7 dBm 3.3 dBm

Per Band Status: D1 D2 D3 U0 U1 U2 U3

Line Attenuation(dB): 24.2 74.6 N/A N/A 59.8 N/A N/A

Signal Attenuation(dB): 24.2 74.6 N/A N/A 57.2 N/A N/A

Noise Margin(dB): 12.4 0.0 N/A N/A 11.9 N/A N/A

jmakepeac · ‎02-23-2015

We have similar numbers on a 2911 router with an ehwic-va-dsl-a:

Attainable Rate:        14600 kbits/s            462 kbits/s
Actual Power:             9.2 dBm                 5.9 dBm
Per Band Status:        D1      D2      D3      U0      U1      U2      U3
Line Attenuation(dB):   27.7    89.4    102.3   8.9     68.6    64.7    N/A
Signal Attenuation(dB): 27.7    N/A     N/A     8.9     0.0     0.0     N/A
Noise Margin(dB):       6.3     N/A     N/A     5.4     N/A     N/A     N/A

We figured it was just line conditions, we're about 1000m from the street cabinet but still think upstream could do better.