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Author Topic: FTTC Solid sync - poor upload  (Read 1285 times)

3tdk

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Re: FTTC Solid sync - poor upload
« Reply #15 on: January 31, 2021, 04:54:37 PM »

OK, that is understood and thank you for taking the time to explain.

Upload is my first priority right now with so much teams and Google Classrooms going on, so I will continue to focus on the throttling issue and the give DLM time to do its thing, assuming a reset does not happen as a side effect of the upload topic.
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3tdk

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Re: FTTC Solid sync - poor upload
« Reply #16 on: February 01, 2021, 07:12:55 AM »

Well, the overnight reset worked, as in I got a new IP.

Sadly no such luck with the upload limiter which is still present  :(



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tubaman

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Re: FTTC Solid sync - poor upload
« Reply #17 on: February 01, 2021, 09:38:02 AM »

I think phone support - second line - is unfortunately the best option here.
A DLM reset should fix the banded download speed, but I suspect the upload issue is in BTs network settings somewhere.
 :)
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3tdk

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Re: FTTC Solid sync - poor upload
« Reply #18 on: February 10, 2021, 08:44:17 PM »

Time for a quick update in case anyone has any wise words... I cannot speak highly enough of BT's front line staff, they have been universally friendly, helpful, and most importanty all seem to agree with me that there is a strange upload issue.

After several cancelled / missed appointments, yesterday an OpenReach broadband engineer did come and re-wire in the cabinet and perform a DLM reset. As expected this has resolved the download rate capping issue, and I'm hoping things will stabilise / improve overnight as the settling period completes.

The upload limit however is still clearly there.
  • The modem currently clocked up at 6651 kbps
  • Openreach speed tester reporting 6.7Mbps, but they only report the maximum speed seen which is the burst before it snaps down to 2Mbps
  • BT support engineer's own test (from their system to the HomeHub 5b now plugged in here reporting 1.8Mbps
  • ThinkBroadband (which I had been recommended to use by BT forum members: 1.6Mbps

Today's support agent recommended another engineer visit, which is booked for Friday though based on previous experience I expect a no-show. When they do come,  I fully suspect they will conclude the same as per Wednesday - i.e. that the line is good, sync rate is steady, and there is no issue on the OpenReach side.

On some speed tests it is possible to see the limiting profile. I have attached a screen grab from speedtest.net. The uplaod speeds are stepped, starting at 6Mbps (the line rate) then reducing to 4Mbps, then stabilising at 2Mbps. That looks like the same profile as BT wholesale speed tester but they don't give you a graph. I never see this on the thinkbroadband test.

Questions on my mind at the moment:

  • Is it likely that the modem is clocked in at 6.5Mbps but the real throughput is always stepped down to 2Mbps (I think this is unlikely based on other plots from friends)
  • The upload "IP profile" on the line as applied in the cabinet is showing as 10Mbps after the BTW "advanced diagnostics" test, but is it possible that this has got stuck at 2Mbps? If so, are Openreach likely to be able to unstick it (I am hoping someone can change it to one setting and then back again, to rule this out, but today's BT agent told me they could not do this)
  • Is is possible that the stepped reduction I'm actually seeing is the cabinet trying to stabilise upload rates, and is therefore healthy behaviour? (the longer you look at these things the more you second-guess yourself...)
  • Today's support agent told me there is no second-line support at BT, they just rely on engineer visits - is this likely to be the case?

Any hints?

 
 
« Last Edit: February 10, 2021, 09:16:42 PM by 3tdk »
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j0hn

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Re: FTTC Solid sync - poor upload
« Reply #19 on: February 11, 2021, 10:30:48 AM »

Quote
Is it likely that the modem is clocked in at 6.5Mbps but the real throughput is always stepped down to 2Mbps (I think this is unlikely based on other plots from friends)

Your stats confirm the modem synced around 6.5Mb.

Quote
The upload "IP profile" on the line as applied in the cabinet is showing as 10Mbps after the BTW "advanced diagnostics" test, but is it possible that this has got stuck at 2Mbps?

The downstream IP profile is calculated from the actual sync speed.
The upstream IP profile is always the package limit. They don't limit the upstream by IP profile like the downstream.

Quote
Is is possible that the stepped reduction I'm actually seeing is the cabinet trying to stabilise upload rates, and is therefore healthy behaviour?

No. The DSLAM does nothing like that.
The DLM controls things like that, telling the DSLAM what profile to use.
The DLM isn't limiting the upstream.

It sounds like an issue beyond the DSLAM, which is down to BT Wholesale.
Ask the engineer to run a speed test (if 1 shows up).
Try stressing to BT that the line and sync rate is fine, but the throughput is stuck.

There's very little an OpenReach engineer can do for some throughput issues. They are responsible for the line between the home and the DSLAM, and the fibre between the DSLAM and the exchange.
The issue appears to me to be speed to the wider internet from the exchange onwards, which is where BT Wholesale take over.

It may need a circuit rebuild. Basically BT Wholesale build the line from scratch.
I'm confident it's a BT Wholesale issue though.
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3tdk

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Re: FTTC Solid sync - poor upload
« Reply #20 on: February 11, 2021, 07:39:22 PM »

Thanks John, we all need a bit of bolstering in these cases!

Modem stats are now as follows now G. INP has kicked in.

Code: [Select]
6. Data Rate: 6624 / 40000
7. Maximum Data Rate: 6624 / 43152
8. Noise Margin: 5.8 / 7.1
9. Line Attenuation: 25.7 / 25.7

I'm sure there is a 40Mbbps/2Mbps package offered by Openreach, and that used to be offered by BT... and I am struggling to believe the modem synced on download at exactly 40Mbps on the nose, with so much SNR to spare.

So when I get an OR engineer here there are a couple of things to check...

1: Prove there is a throughput issue and get it documented, probably by hanging a cable out the window to avoid any COVID risk.
2: Can the OR engineer force a temporary change to the line profile ordered by BT, in case (I suspect) this is stuck in the cabinet at 40/2 instead of the 50/10 which should have been allocated when Fibre 1 was ordered. I am hoping a simple toggle of the settings might unlock this.
3: Is it a problem upstream of the cabinet, and if so get it documented, to hopefully prompt BT Isp to kick off another piece of work with BT Wholesale.

First thing is to get the OR engineer here. I am not hopeful as have 2 appointments cancelled with no notification so far, the last guy only arrived when the BT tech bypassed their own system and went straight to an Openreach portal.

Thanks for the support and I will keep updating.

Derek
« Last Edit: February 11, 2021, 08:21:56 PM by 3tdk »
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burakkucat

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Re: FTTC Solid sync - poor upload
« Reply #21 on: February 11, 2021, 10:32:51 PM »

I may not be remembering correctly but I believe there were the following Openreach products available for ISP's / CP's to base their FTTC (VDSL2, ITU-T G.993.2) based services upon --

18/2
40/2
40/10
55/10
80/20

(All DS/US Mbps.)

It looks to me as if your service has been provisioned on the Openreach 40/10 Mbps product.
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3tdk

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Re: FTTC Solid sync - poor upload
« Reply #22 on: February 11, 2021, 10:42:26 PM »

Yes, thanks for that.

I would say the 40/2 product, as it is the 2Mb upload limit I am trying to get fixed.

The only confusion there is that the "extended info" test (tap2 info? ) shows a 10mbps IP profile on upload, where we are clearly limited to 2. ( I get the IP upload profile from https://speedtest.btwholesale.com/)

My hope is that there is one setting in the cabinet (2Mbps) and another in an online database somewhere (10Mbps), so when I do the check online it shows 10 whereas I'm actually seeing 2...

And I'm banking on this statement from SIN498

Note : The upstream throughput is also constrained on the DSLAM to the upstream rate requested in the order, i.e. 2 Mbit/s, 10 Mbit/s or 20 Mbit/s, so even if the VDSL2 upstream line speed is higher, the upstream throughput is constrained to the level ordered for the product.


Thank you so much for the comments, I am learning!
« Last Edit: February 11, 2021, 10:45:23 PM by 3tdk »
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burakkucat

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Re: FTTC Solid sync - poor upload
« Reply #23 on: February 11, 2021, 11:38:25 PM »

I still believe that your service has been built on the 40/10 Mbps product by looking at the synchronisation speed reported by your CPE.

Modem stats are now as follows now G. INP has kicked in.

Code: [Select]
6. Data Rate: 6624 / 40000
7. Maximum Data Rate: 6624 / 43152
8. Noise Margin: 5.8 / 7.1
9. Line Attenuation: 25.7 / 25.7

Look at the line numbered 6., above. That is the synchronisation speed and it shows ~6.6 Mbps US and 40 Mbps DS. Hence the Openreach product has to be, at least, the 40/10 Mbps product.

I strongly suspect there are at least two BT Wholesale related problems: (1) using the wrong Openreach product (2) constraining the US to 2 Mbps. Both would be resolved by a "circuit rebuild", as j0hn mentioned.
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3tdk

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Re: FTTC Solid sync - poor upload
« Reply #24 on: February 12, 2021, 06:38:42 AM »

OK, that's clear and thank you all so much. I will try to encourage BT & OR that is the way forward.
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j0hn

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Re: FTTC Solid sync - poor upload
« Reply #25 on: February 12, 2021, 12:34:37 PM »

As above if you were on 40/2 OpenReach product then the sync would be capped at 1,999.
From the current sync rate I would say you are definitely on 40/10.

The IP profile suggests BT Wholesale also have you provisioned on 40/10, though something somewhere is indeed configured incorrectly.

Edit: I'll add to your comment...

Quote
Can the OR engineer force a temporary change to the line profile ordered by BT, in case (I suspect) this is stuck in the cabinet at 40/2 instead of the 50/10 which should have been allocated when Fibre 1 was ordered.

Fibre 1 is not 55/10.
It is sold as "average speed 50Mb/s".
However, if you have low estimates then BT will provision on 40/10.
You have been provisioned on 40/10 as you can see from your sync.
Getting BT to increase this to 50/10 may fix the upstream issue at the same time.
The BT forums are great for getting the package changed to 55/10.
An OpenReach engineer can't change this. It must be the ISP.
The higher package cost the ISP more money so would need them to order it.
The line could reach over 50Mb if it was on 55/10 and the DLM lowers the noise margin (SNRM).
« Last Edit: February 12, 2021, 12:43:00 PM by j0hn »
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3tdk

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Re: FTTC Solid sync - poor upload
« Reply #26 on: February 12, 2021, 04:36:53 PM »

OK, that's a good suggestion. We are right on the limit though (and 40Mbps would be close to the BT Wholesale line expectation for a this line), so it will take some convincing.

Code: [Select]
VDSL Range A (Clean) MAX 41.4 MIN 25
I have hit the "we won't investigate upload speeds" wall with BT agents today who offered to send me a USB to ethernet adapter and now tell me I should have a home tech expert come in a week Friday. So I have submitted a formal complaint that they are throttling my line (in contravention of https://www.bt.com/help/broadband/bt-s-approach-to-broadband-traffic-management ).

I will have another go on the BT community forums though to see if I can get the 55/10 enabled, in the hope that will clear a path through the system.
« Last Edit: February 12, 2021, 04:52:36 PM by 3tdk »
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3tdk

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Re: FTTC Solid sync - poor upload
« Reply #27 on: February 14, 2021, 10:11:00 PM »

Well the BT community forums seem to go round and round asking me to run speed tests but not really addressing the fundamental limit.

Has anyone got any advice on how to coach the "Home Tech Expert" (is this actually an engineer?) to believe there is really a problem with a speed limiter. I have an 8-page powerpoint slide deck I wrote today just to get my chain of logic right (it's bigger than 300kb though otherwise I would have shared it for peer review!)

I am thinking:
1/ Show them a print out of the BT wholesale speed estimates and the BT "your line will deliver this" screen
2/ Get them to run the "My BT" speed tester, which I understand runs direct between the hub and the bRAS (it shows the limited speed)
3/ Get them to run a speedtest.net and a BTW speed test, demonstrating that the line is capable of the full speed but is throttled

then the complex bit... draw a diagram of how an internet speed limiter works and why it will result in exactly the profile of speeds they are seeing! The slide I've attched is the best I can do so far, but I am assuming some knowledge of how TCP/IP networks work, which means I am talking to an engineer...

trying to walk them down the road of discovering the issue for themselves.
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3tdk

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Re: FTTC Solid sync - poor upload
« Reply #28 on: March 19, 2021, 08:54:52 PM »

Well, a month and 3 days after the last post here, I'm really pleased to report the problem is fixed.

Summary (my personal call log on this is 157 lines and started on 1st Feb so too long to be of interest): This got escalated to a weekly review between BTW and OR, and between the two they identified a parameter which should have been 10Mbps and was set to 2Mbps. After being reset properly in line with the package rate, we are now seeing a reliable 6Mbps which is right on target.

I am really thankful to the other posters on this forum who gave me the energy and confidence to chase this through with BT. You get asked so many questions during these topics, you can start to doubt yourself, and your responsed helped me through some of those dark times. Thankfully the PPT was never needed...

In all truth, I also cannot speak highly enough about the BT community Forum moderators who took the problem seriously from the first time it was raised with them and were very reliable in their actions, eventually chasing it through OR and BTW to get it escalated to a joint review session. Sadly, getting to the point where it was raised with them took quite a bit of chasing and I was lucky to have 2 issues running in parallel, one of which eventually allowed me to get my issue raised to forum level (thank you if anyone on this forum was involved in poking that, if so you are an  :angel: as I had lost all hope at one stage)

In the meantime during all the round-the-loops I was asked to do, someone asked me if my line was stable. BT don't provide tools to work that out so I have been working on a python script to monitor the Smart Hub 2 from a Raspberry Pi (fairly easy to expand to other devices), which is posted to the forum here: https://forum.kitz.co.uk/index.php/topic,25733.0.html. Screen grab attached showing the last 2 weeks of connection data.
« Last Edit: March 19, 2021, 09:45:10 PM by 3tdk »
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burakkucat

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Re: FTTC Solid sync - poor upload
« Reply #29 on: March 19, 2021, 11:37:34 PM »

Well, a month and 3 days after the last post here, I'm really pleased to report the problem is fixed.

Excellent news!  :dance:

Quote
In the meantime during all the round-the-loops I was asked to do, someone asked me if my line was stable. BT don't provide tools to work that out so I have been working on a python script to monitor the Smart Hub 2 from a Raspberry Pi (fairly easy to expand to other devices), which is posted to the forum here: https://forum.kitz.co.uk/index.php/topic,25733.0.html. Screen grab attached showing the last 2 weeks of connection data.

That certainly looks useful. Just one comment, having peered at the screen-scrape: Perhaps a different choice of well contrasting colours would be beneficial.  :-\
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