Draytek Vigor 2860 new Firmware & modem codes

[#1]

Hello

This is my first post so apologies if I have not found answer somewhere else.

My VDSL speed has been very good  77mps/20Mps and very stable for over 1 year until last week. 

I believe that vectoring  (G.IMP ) is enabled  on the upstream but not on downstream ReTX=0 on Down and ReTx=1 on upstream.  I am on FAST (not interleave) and have low error rates. The attenuation and SNR margin show very little fluxuation.  Two weeks ago Downstream dropped suddenly to 54Mps and the IP profile has capped the speed to this level. I am confident it is not at my end I have a 5C Master socket, no extensions and a .5m Cat 6 modem cable straight into the router. I have waited 10 days to see if this speed resets its self back to 77Mps but it hasnt.

ATU-R Information
	Type:	VDSL2
	Hardware:	Annex A
	Firmware:	05-07-06-0D-01-07
	Power Mngt Mode:	DSL_G997_PMS_L0
	Line State:	SHOWTIME
	Running Mode:	17A
	Vendor ID:	b5004946 544e0000
ATU-C Information
	Vendor ID:	b5004244 434db12d [BDCM]
Line Statistics
	Downstream             Upstream                 Actual Rate 53645 Kbps 19999 Kbps Attainable Rate 53286 Kbps 20788 Kbps Path Mode Fast Fast Interleave Depth 1 1 Actual PSD 6. 9 dB 15. 3 dB       Near End                  Far End                    Trellis ON ON Bitswap ON ON ReTx 0   1   SNR Margin 3 dB 5 dB Attenuation 16 dB 18 dB CRC 24 27961 FECS 0 s 77025 s ES 21 s 17118 s SES 0 s 3 s LOSS 0 s 0 s UAS 30 s 8715 s HEC Errors 0 0 RS Corrections 0 0 LOS Failure 0 0 LOF Failure 0 0 LPR Failure 0 0 NCD Failure 0 0 LCD Failure 0 0 NFEC 100 32 RFEC 4 16 LYSMB 5238 16

I have noticed that my firmware is 6 months out of date and therefore I want to upgrade in due course.  I have allways used modem code 57d17 code on previous upgrades as reccomended.

My question is has anyone upgraded to 3.8.4.5 software and which code gives the best performance as 3 other vector supporting modem codes are also available  on this release?  I attach the release note. 

 I have logged this drop in speed with Plusnet and I do not wish to change anything at my end until they have responded (Still waiting!!!!) but I would like to hear other users experiences and what has worked best for them. I do wonder if Openreach have changed the modem software at  the cabinet end but it would be impossible to find that out.  Finally I noticed the tone burst profile has changed with high frequency bins on the downstream being shifted down to the low frequency end.  Does this explain the drop in speed?

Any help would be appreciated.

Regards

Dave

[#2]

I'm fighting with constant WAN drops on a 2860 (although I have tried other routers too).  You, like me, have what appears to be a very high noise figure (low signal) on the down - 3db.  Draytek UK stopped helping me as mine goes below 6db.  My upstream SNR is 9 or 10db and never fluctuates.  My down starts at 9db and slowly drops eventually to 0db, which appears to be causing my WAN drops.  I've had a PN fault open since April and getting no where.

I'm running latest Draytek "BT recommended" firmware - I have G.INP (re-tx) on both up and down.  Tried all of them and I would say Vector 2 was the most stable.  But Draytek kept telling me to go to the "BT recommended" one with "default" modem code.

[#3]

Hi,

Thank you for your quick reply. I would have responded earlier had it not been for a powercut which took out the village and the Mobile mast!! All back on line again.

 It is interesting  that your SNR margin is also very low, that it is changing over time and that the lower it gets  the WAN drop out.  Do you get a lot of down stream errors? Mine is low I think because I am very close to the cabinet (less than 200M).

 I think unless I have got the wrong end of the stick that we should be looking for a very low SNR margin not a high one. and that we also want a high SNR  I have come to this conclusion by visiting Kitz broadband Site http://www.kitz.co.uk/adsl/linestats.htm  and http://www.increasebroadbandspeed.co.uk/SNR-tweak.  I do wonder why some modems quote snr and others snr modem in the stats it is confusing.      Do you know the difference between " far snr margin" and "snr margin"  which is stated when you telnet the modem and use the vdsl status command?

I am assuming you are running the latest May 2017 software 8.4.5-02? 

I have used the Draytek 2860n Plus for 3 years now and found it to be very stable on the vdsl line until the sudden speed drop. I also noticed that changing to a 5C master socket and a Cat 6 modem cable imroved my sync speed from 73Mps to 77Mps whilst the upstream has allways remained constant at 20Mps.

If I find out anything useful I will reply back to this post.

Dave

[#4]

Sorry for the late reply - yes - it's confusing.  Mainly because it seems router manufacturers do not really specify what their figures are.  Are the SNR or SN Margin?

I think a high SNR is what we want, but as most consumer routers show margin rather than the actual SNR value, maybe you are correct.  But when I mentioned to Draytek that (according to their stats page) their SNR was showing as less than 6db, they said that was bad.  So are they confused too?  It certainly seems to cause drops when it goes low.  So is their page showing SNR or SN Margin?  According to Kitz (link you pasted which I have read before), they say most routers show margin, not true SNR.  If you telnet into Draytek, it seems to back that up as it then states "margin".

> vdsl status
---------------------- ATU-R Info (hw: annex A, f/w: annex A/B/C) -----------
Running Mode : 17A State : SHOWTIME
DS Actual Rate : 71303000 bps US Actual Rate : 19999000 bps
DS Attainable Rate : 69857624 bps US Attainable Rate : 22999000 bps
DS Path Mode : Fast US Path Mode : Fast
DS Interleave Depth : 1 US Interleave Depth : 1
NE Current Attenuation : 12 dB Cur SNR Margin : 5 dB
DS actual PSD : 2. 2 dB US actual PSD : 12. 9 dB
NE CRC Count : 115 FE CRC Count : 8579
NE ES Count : 91 FE ES Count : 6751
Xdsl Reset Times : 0 Xdsl Link Times : 1
ITU Version[0] : b5004946 ITU Version[1] : 544e0000
VDSL Firmware Version : 05-07-06-0D-01-07 [with Vectoring support]
Power Management Mode : DSL_G997_PMS_L0
Test Mode : DISABLE
-------------------------------- ATU-C Info ---------------------------------
Far Current Attenuation : 14 dB Far SNR Margin : 7 dB
CO ITU Version[0] : b5004244 CO ITU Version[1] : 434da48c
DSLAM CHIPSET VENDOR : < BDCM >

The Far SNR Margin is (ASAIK) the upstream SNR whereas the Near End (NE) SNR Margin is the downstream.

Anyway - how are you getting on?  Any ideas?

[#5]

By the way - I have a 2860Vac and running:

Model Name	Vigor2860Vac	System Up Time	109:47:58
Router Name	DrayTek	Current Time	2017 Aug 24 Thu 11:23:18
Firmware Version	3.8.4.5_BT	Build Date/Time	May 12 2017 16:28:21