VDSL slow upstream

[#1]

Today 18th Oct VDSL sync is

DOWN  Speed 2291kbps UP Speed 43999kbps SNR Upstream 15dB SNR Downstream 8dB.

Yesterday 17th Oct at 20:01

DOWN  Speed 411kbps UP Speed 43999kbps SNR Upstream 10dB SNR Downstream 4dB.

Down stream seems to remain High but Upstream seems to start high then slowly drop over time.

Seems to be unstable Upstream.

Please help - 4 Openreach and one Qube Engineer have not solved issue.

Yesterday am Upstream was 2633kbps. I replaced Draytek with Plusnet Hub One for 30mins and it was the same DSL speed as the Draytek.

Drayek Modem log

> vdsl status

  ---------------------- ATU-R Info (hw: annex A, f/w: annex A/B/C) -----------
   Running Mode            :      17A       State                : SHOWTIME
   DS Actual Rate          : 43999000 bps   US Actual Rate       :   411000 bps
   DS Attainable Rate      : 35979132 bps   US Attainable Rate   :   485583 bps
   DS Path Mode            :        Fast    US Path Mode         :        Fast 
   DS Interleave Depth     :        1       US Interleave Depth  :        1 
   NE Current Attenuation  :       19 dB    Cur SNR Margin       :        3  dB
   DS actual PSD           :    -4.-8 dB    US actual PSD        :    -4.-8  dB
   NE CRC Count            :       39       FE CRC Count         :    42426
   NE ES Count             :       11       FE  ES Count         :    17711
   Xdsl Reset Times        :        0       Xdsl Link  Times     :        8
   ITU Version[0]          : fe004452       ITU Version[1]       : 41590000
   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 :       39 dB    Far SNR Margin       :       10  dB
   CO ITU Version[0]       : b5004946       CO ITU Version[1]    : 544eb206
   DSLAM CHIPSET VENDOR    : < IFTN >

>  

> vdsl status more

  ---------------------- ATU-R Info (hw: annex A, f/w: annex A/B/C) -----------
                  Near End        Far End    Note
 Trellis      :      1               1
 Bitswap      :      1               1
 ReTxEnable   :      0               1
 VirtualNoise :      0               0
 20BitSupport :      0               0
 LatencyPath  :      0               0
 LOS          :     12              10
 LOF          :      2               0
 LPR          :      0               2
 LOM          :      0               0
 SosSuccess   :      0               0
 NCD          :      0               0
 LCD          :      0               0
 FECS         :      0            16436061 (seconds)
 ES           :     11            17711 (seconds)
 SES          :      3            2089 (seconds)
 LOSS         :      0             890 (seconds)
 UAS          :     27            1750844 (seconds)
 HECError     :      0               0
 CRC          :     39            42426
 RsCorrection :      0               0
 INP          :      0             215 (symbols)
 InterleaveDelay :      0              14 (1/100 ms)
 NFEC         :     13              32
 RFEC         :      0              16
 LSYMB        :    108              16
 INTLVBLOCK   :     13              32
 AELEM        :      0            ----

>  

Equipment

Draytek Vigor 130 – 2.5 years old – latest firmware installed 3.8.5.1_BT

Router ASUS ZenWiFi XT8 – 1 year 5 months old – latest firmware installed.

History.

Started Aug 9 – 7 drop-outs followed by low downstream (24.18Mbps) and upstream (0.91Mbps).

Aug 24 – First Openreach – High resistance – connection remade – Downstream (43.2Mbps) and upstream (11.4Mbps).

More drop-outs followed by drop in downstream (16.56Mbps) and upstream (0.97Mbps).

Sep 5 – 2^nd Openreach – remade connections and did lift and shift as line appeared okay – Downstream (42.79Mbps) and upstream (12.70Mbps).

More drop-outs followed by drop in downstream (6.00Mbps) and upstream (0.14Mbps).

Sep 14 – QubeGB Engineer – Checked home equipment was fine and was not the issue.

More drop-outs followed by sudden return to normal speed on Sep 16 - downstream (43.20Mbps) and upstream (11.4Mbps). However more drop-outs.

Sep 20 – 3^rd Openreach – remade all connections and could not find anything wrong as line speed still good. (43.40Mbps) and upstream (12.00Mbps).

Next day Sep 21 – Speed even higher - downstream (50.60Mbps) and upstream (13.20Mbps).

Sep 22 - More drop-outs though recovered to good speed downstream (40.00Mbps) and upstream (11.07Mbps).

Sep 25 – Outage in area.

More dop-outs with recovery to good speed. However, upstream seemed to be slowly dropping over time from 13.94Mbps to 5.37Mbps.

Oct 10 – 4^th Openreach – Observed good downstream but slow upstream. Did extensive testing with kit over a long period. Could not find any fault with line or dsl – he stated downstream sync should be 40Mbps to 50Mbps and upstream sync should be 10Mbps to 14Mbps. Reconnected home equipment and he testes and confirmed that Downstream sync was 40Mbps yet Upstream sync was only 4.3Mbps – half what should be. Said he could not find any fault and left.

Still some drop-outs. Yet again Good Downstream sync (43.999Mbps) but upstream sync slowly dropping to 0.411Mbps (Oct 17)

Notes :

Before 2^nd Openreach came out swapped Modem for Netgear D6400 in bypass mode. Still having same issues.

When 3^rd Openreach engineer placed Plusnet Hub One on the line and confirmed good sync speed so said he could not do any more. Replace later with Draytek and got exactly same speeds.

Moderator's note: Post released from autpomatic spam filter and duplicate removed

[#2]

I have a very similar problem. My line has had ongoing intermittent dropout problems for years which endless Openreach visits have failed to permanently solve. They usually find something not quite right however which appears to give a temporary fix. Sometimes the connection will stay up for days and sometimes might fail repeatedly over several hours. There's no pattern to it.

Recently it has started a new habit of reconnecting ok downstream, typically 50Mbs but upstream could be anything from less than 1Mbs to 15Mbs. Rebooting the modem usually restores the upstream speed to greater than 10Mbs. I've tried different modems with the same result. I'm resigned to having to live with it until I can finally get full fibre.

[#3]

Thanks for your response Rising Star.

However, I think mine is a slightly different problem. Openreach come aound mess about with joints and then speed goes up.

Speed usually drops over a period of time whilst Downstream usually remains good though drops slightly.

Rebooting Modem has no effect. In fact when it was slow upstream of 0.417Mbps I actually swapped the Draytek Vigor 130 for the Plusnet Hub One. After it powered up and connected the speed was exactly the same. So obviously something Openreach end. It seems that Openreach can't actually fault find apart from looking at the cable ie. can't or won't monitor the line or look at the DLM or DSLAM settings. Last engineer connected his equipment and ran a long test (15mins). He said that there was nothing wrong with the line or the DSL and I should be getting good speeds of around 45Mbps down and 11Mbps to 14Mbps up. So I reconnected my Modem and he checked the connection and it was 40Mb Down and 4.3Mbps up. Upstream half of what it should be. He said that the cable and DSL were fine and left!

Since then got Plusnet to reset the DLM Speeds went up to 48Mbps Down and 13Mbps Up, what it should be.

Later on the same day there was a line drop/disconnect and speed went down to 46Mbps Down and 7Mbps Up, so far still stable. I think I am going to be in your boat of waiting for full fibre and just keep annoying Plusnet when the speed drops to a very low rate.

[#4]

Hey @K5Hall The DLM reset that happened the other day will up you into a stabilisation period. We'll need to wait 3 working days and if this hasn't resolved, then we can look into this further for you. 

[#5]

@K5Hall 

It sounds a bit like you have REIN in the low frequency band on your line. Try reinstalling your Hub 1 and running Routerstats (http://www.vwlowen.co.uk/RouterStatsHub/routerstatshub.htm) 24/7 for a few of days to monitor the SNR. This might give us a clue.

[#6]

@K5Hall 

With an issue like this it can be helpful to run router stats  or dsl stats  not sure if a version supports your modem but there is one which supports the Hub One Hub One router stats 

If you have a windows pc which can left turned on and connected directly (wired) to the Hub One, then it will be possible to monitor the behaviour of the DSL connection.

If you want to give it a try it might highlight some line issues, it is recommended to change the sample  to as follows, this setting is found under the Config tab 

The program still runs when minimised and should be left viewing the Noise Margin tab when running.

The noise margin graph is the most useful as it will capture changes in noise margin.

Is the DSL cable from the modem connected directly to a master socket or an extension? It would also be recommended for now connecting the DSL cable to the test socket found behind the faceplate of the master socket, you will need an in-line ADSL filter.

HTH

[#7]

Thanks for the helpful comments.

Previously this year Openreach have changed the Master socket twice, once because an impairment was detected and second in case it was part of a faulty batch. Neither change improved reliability.

The last engineer ran an extended line quality test between the cabinet and the Master socket for 15 to 30 minutes but it didn't show up any problems. He wondered if it could be interference via the ethernet connection from the modem to my network but I tried isolating the modem from all wired connections apart from the DSL input for 24 hours but again it made no difference.

When I have an opportunity I will switch back to my Hub One modem and try monitoring the stats as suggested.

Ian

[#8]

Thanks for all the helpful suggestions.

Today Sunday 22nd October had a line drop out.

Noted speed drop on Modem Down 49.649Mbps SNR 6.00dB Up 4.437Mbps SNR 6.00dB.

Observing modem DSL status noticed that SNR Upstream was fluctuating between 0dB and 13dB and Downstream between 1dB and 6dB.
Later on checked again when it appears to have stailized.

Modem Down 49.786Mbps SNR 6.00dB Up 1.963Mbps SNR 16.00dB.

Definitely looks like there is an occasional REIN issue with the line that is upsetting the DLM.

Unfortunately putting the Plusnet Hub One back on is an issue as I need a MESH system due to the house having warm air ducting causing dead spots and my daughter works from home. So until I put holes through the ceilings and run cable it is a non-starter. Don't believe it is anything with my end as system has been up and running for over 1.5years and 4 engineers state it is not my equipment.

[#9]

I've been running the stats monitor over the weekend and it shows the downstream snr reasonably stable at around 6dB but the upstream snr is continuously varying with periods of large fluctuations and then periods of small fluctuations. Twice on Sunday a large dip in the upstream snr was followed by a dsl connection dropout. Although it's obvious there is a problem most likely with interference I can't see how the cause can ever be found. I've attached sample images of the periods of dropout and one when all is stable!

[#10]

Looks like you have much similar problems. I only dropped out once on Sunday around 12:44 GMT (Modem operates on GMT) which would be 13:47 BST. I then had varying SNR - you don't happen to live near me???? or have DSL from the same cabinet?

Suspicious in that it was the same day. Surely Openreach must have some monitoring at the cabinet end to detect problems themselves. Also given the noise profile i.e. affects Up more than Down they should be able to determine as to whether it is cabinet or residence end. One Openreach engineer said that this upstream issue typically signified a problem at the cabinet end, so perhaps they do know something?

By the way mine dropped out again at 11:11 speeds now dropped to Down 49.152Mbps SNR 7dB Up 0.344Mbps SNR 7dB.

I would assume that the DLM would automatically try to increase the speed to get to a "good" speed. It just seems to have a hiccup and then drops the upstream speed slightly. It then does the same every hiccup until you have no upstream.

[#11]

It would be quite a co-incidence if you are also in the Southend area!

I've had 3 dropouts since I started monitoring monitoring Saturday evening. Whilst the downstream speed has changed little the upstream went from 13Mbs to 10.5Mbs and then 5Mbs with each dropout. To restore it back up again I will probably have to reboot the modem. I find that disconnecting and reconnecting alone does not reset the speed.

I suspect these problems are quite widespread, however I find most users never check their speeds or reliability, only complaining when they lose service completely. You would think that Openreach would be aware of unstable speeds but I doubt they would voluntarily look into it, especially now they will be moving us to full fibre one day, however for me this could still be more than 2 years away!

[#12]

After the upstream speed settled at 5Mbs it all remained fairly stable from Sunday to today.

I thought I'd try a reboot and this restored the upstream to 12.5Mbs but with an immediate deterioration in snr.

As a result the connection soon went down but then reconnected with a higher 15Mbs speed and even worse snr. Three dropouts later the upstream is now 0.7Mbs. Obviously there is a trade-off between upstream speed and snr and consequently susceptibility to dropouts. Whilst the cabinet is managing this ok with the downstream speed it is obviously unable to do the same for the upstream speed eventually resulting in a ridiculously low upstream speed.

This all point to a problem with the cabinet either electrically or software related and requires investigation by Openreach.

[#13]

---

@chroma2000 wrote:

This all point to a problem with the cabinet either electrically or software related and requires investigation by Openreach.

---

Surely this points to REIN rather than a cabinet fault? The SNR needs to be higher to cope with the noise, and that reduces the speed. 

Electrical interference (noise) can be produced by a variety of things - from fluorescent lighting, a heating system or refrigerator  pump, nearby industrial activity, or in rural areas (like mine) electric fences. The noise may be transmitted through the mains supply (the router power supply won't filter all noise out),  or it may be induced in the internal or external cables.

Mains noise can be eliminated as a cause by powering the router from a UPS while switching everything else off (preferably at the main fuseboard). If that makes no difference then look further afield - at anything along the route of the cabling (all the way to the cabinet). A transistor radio can be used to detect interference - you can find guides online.

[#14]

Why is upstream more susceptible to interference than downstream? There is no regular pattern to it and I can't think of anything in my house which could coincide with the interference, in any case the internal cable run only accounts for a small percentage of the total run from the cabinet and is not close to any other cables unlike the rest of the run.

I don't think I will be wandering up and down the road looking for possible sources of interference. Even if I found any suspects, how would you eliminate them?

More realistically why cannot the Openreach equipment better determine the optimum upstream speed, which from my observations would be around 5Mbs. As it is now, it just keeps lowering the speed until it is <1Mbs which is ridiculous. This then requires a reboot of the modem to reset, but it then resyncs too high and the downward cycle starts all over again.

[#15]

DLM reset obviously worked for a short time but then drop-outs and decreasing upstream.

DSL status - Down 51.248Mbps SNR 6.00dB Up 0.800Mbps SNR 16.00db.

Fifth Openreach engineer came out - unfortunately the same engineer that came out 3rd time (3rd Openreach).

He again tested the line and I could see the readout saying that he was getting 800k down and 51M up so exactly what my Modem was seeing.

He did lots of monitoring and testing including a portable DSLAM and said he could not find anything wrong with the line.

He then got the Plusnet Hub One on and connected to it showing speed improvement.

He stated that :

I may have a double firewall that could be causing the issue as it was a separate Modem and router and that it could incompatibility between them

their equipment expected a certain modem connected (ISP provided) and that this could be the cause as the cabinet equipment was not seeing the "right" modem

I could be downloading a huge file and that the DLM would borrow from the upstream to try and increase the Downstream and so set the upstream lower.

Anyway he said that they were only responsible for the cabinet to the master socket and that again the fault was with my side.

So I reconnected my NAS and printer to the Plusnet Hub One.

He left and within 1 Hour the Plusnet Hub One line dropped and the speed decreased to Down 48Mbps Up 1.8Mbps.

Phoned him and he saw the speed drop and said that it was the DLM adjusting the line however he again believed it to be my equipment and got me to disconnect everything from the Plusnet Hub One and he would do more testing and call back.

Modem dropped out a few times whilst waited for call back.

Called back and said that everything his side was fine and that the speed was now up. He also said that it was obviously something my side loading the router.

Now I'm no expert but I am a semi-retired Electronics Engineer but as far as I am aware nothing my side of the router can affect the DSL line speed and that is down to them setting it - please someone confirm as to whether I am right or wrong.

Also I don't believe that the DLM will borrow speed from the DSL upstream to deliver a faster download (their side determine up and down speed) - please someone confirm as to whether I am right or wrong.

I also believe that downloading huge files will not affect the DSL Up or Down speeds as the file is limited to the down speed and will take the required length of time - please someone confirm as to whether I am right or wrong.

Please someone check my sanity on this!!!