DrayTek UK Users' Community Forum

Help, Advice and Solutions from DrayTek Users

2862 "VDSL SNR" not working

  • mgillespie2
  • Topic Author
  • Offline
  • Junior Member
  • Junior Member
More
05 Feb 2021 07:53 #98365 by mgillespie2
2862 "VDSL SNR" not working was created by mgillespie2
Setting the delta in the telnet terminal, the command is accepted and it restarts the modem, querying the offset it shows its taken, however my stats never change.

I started off with some small changes "vdsl snr -10" now upto "vdsl snr -30"

My line stats always show snr 11 and the line speed is unchanged.

Code:
---------------------- ATU-R Info (hw: annex A, f/w: annex A/B/C) ----------- Running Mode : 17A State : SHOWTIME DS Actual Rate : 73999000 bps US Actual Rate : 19999000 bps DS Attainable Rate :103312656 bps US Attainable Rate : 32166000 bps DS Path Mode : Fast US Path Mode : Fast DS Interleave Depth : 1 US Interleave Depth : 1 NE Current Attenuation : 11 dB Cur SNR Margin : 11 dB DS actual PSD : 0. 9 dB US actual PSD : 12. 4 dB NE CRC Count : 0 FE CRC Count : 546 NE ES Count : 0 FE ES Count : 487 Xdsl Reset Times : 0 Xdsl Link Times : 4 ITU Version[0] : 00000000 ITU Version[1] : 00000000 VDSL Firmware Version : 07-07-09-05-01-07 [with Vectoring support] Power Management Mode : DSL_G997_PMS_L0 Test Mode : DISABLE -------------------------------- ATU-C Info --------------------------------- Far Current Attenuation : 13 dB Far SNR Margin : 15 dB CO ITU Version[0] : b5004244 CO ITU Version[1] : 434da4a1 DSLAM CHIPSET VENDOR : < BDCM >


This is taken at "vdsl snr -30", I have gone back to 0 as I can see some CRC errors. (EDIT, see similar FE CRC at 0 delta)

Please Log in or Create an account to join the conversation.

More
05 Feb 2021 15:14 #98368 by hornbyp
Replied by hornbyp on topic Re: 2862 "VDSL SNR" not working
Have you seen this Draytek Knowledge Base article ? https://www.draytek.com/support/knowledge-base/4800

Amongst other things, it says :-

Draytek wrote: NOTE: The new SNR value will not be exactly the value of 8 dB plus 5 dB. It is because the actual synchronization result depends on the negotiation with DSL IPDSLAM; however, Vigor Router will try to get synchronization with a higher SNR value.

If the SNR value or the DSL stability is not as good as you expected, please try other DSL modem codes to improve



In my case, I tried every available firmware for my 2860 and noted significant differences in download speeds (before I discovered the 'VDSL snr' command - and started messing with that too :wink: ).

By all accounts, this command works, by 'lying' about the strength of the signal, thereby encouraging the other end to up-the-ante.
See: https://www.increasebroadbandspeed.co.uk/SNR-tweak

IncreaseBroadbandSpeed wrote: As we will discuss, since a modem measures the downlink SNR and reports this measurement back to the BT exchange equipment (which then sets the downlink connection speed), it is possible (with some modems) to adjust this measurement so that the BT exchange equipment believes that the SNR is higher than it really is so that it sets a higher connection speed than it would have done.



Finally, I found another KnowledgeBase article, that explains the output from the 'VDSL status' command: https://www.draytek.co.uk/support/guides/kb-dsl-status-more

In my case, both "FE CRC Count" and "FE ES Count" are around 20000, or so. They acquire these values shortly after startup - but don't seem to change after that (so I ignore 'em :D )

Please Log in or Create an account to join the conversation.

Moderators: Chris, Sami