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Upload speed killed by interleaving

edandsuet
Hooked
Posts: 9
Registered: ‎11-08-2017

Upload speed killed by interleaving

 

My line speed was reset after I reported an intermittent fault on my line, and for 2 days (Monday and Tuesday) I got:

ping 17ms

download 7.5 Mbps

upload 0.8 Mbps

(I have 20+ readings showing these results).

On Wednesday, Plusnet turned on interleaving, after which I got:

ping 35ms

download 7.3 Mbps

upload 0.00 Mbps for about the first 5-6 seconds, then about 0.1 Mbps for another couple of seconds then gradually rising to 0.2 - 0.3 Mbps

(again lots of readings showing this)

On Thursday, the BT engineer visited and found an intermittent line fault (that he couldn't explain) 250m from the house, and bypassed the faulty section of line (we are 190m from the cabinet but the line was 300m from the cabinet so he was able to cut 110m out including the section showing the fault).

After fixing the fault I now get:

ping 35ms

download 9.0 Mbps

upload 0.00 Mbps for about the first 5-6 seconds, then about 0.1 Mbps for another couple of seconds then gradually rising to 0.2 - 0.3 Mbps

 

 

I have asked Plusnet to turn interleaving off (as this seems to have caused the upload issue).  They are switching interleaving to automatic, so I hope this will turn it off.

Interested to learn if anyone else has experienced this issue, and if there was any other solution.

 

9 REPLIES 9
RealAleMadrid
Aspiring Hero
Posts: 2,713
Thanks: 1,395
Fixes: 59
Registered: ‎07-07-2009

Re: Upload speed killed by interleaving

Speed tests are not very useful in this type of problem, the router stats showing sync speeds and other parameters would give much more detailed information. It is unlikely that the application of interleaving would cause the problem you are seeing. The fact that BT found a fault on the line has probably got a lot to do with it. You now have a nice short line to the cabinet, is FTTC available?

edandsuet
Hooked
Posts: 9
Registered: ‎11-08-2017

Re: Upload speed killed by interleaving

Yes FTTC is now available to me and I am considering.

But, switching to fibre could increase my upload and download speeds, but  still leave me with the same dead time at the start of an upload, which is the biggest issue to me.

Despite having the fastest download speed I have ever had at 9Mbps, the dead time on the upload is a real pain, more so than the peak upload speed.  I don't have this dead period on download which starts immediately.

 

This upload dead period only started when the interleaving was switched on, and has been consistent ie. I never saw it before Wednesday, and it has always been there since Wednesday.

Upload is still exhibiting the strange dead period this morning (from 6 up to 8 seconds this morning).  Interleaving is being switched to automatic on Monday, so will see if this cures the problem.

 

 

edandsuet
Hooked
Posts: 9
Registered: ‎11-08-2017

Re: Upload speed killed by interleaving

Just to be clear, the fault on the line was fixed Thursday, so the issue with the dead upload period fits perfectly with the timing of interleaving being switched on, not the timing of the fault fix.

 

I understand that interleaving shouldn't cause this, but equally the engineer was also at a loss to explain the type of intermittent fault he found on my line (he saw noise, ran a line test showing line was all clear, some time later saw noise again).

Fixing the fault (which does seem to have worked as I haven't seen any noise on the line since Thursday) hasn't fixed the dead upload period.

Note that I continue to be connected to the test socket throughout this whole period, so no other outside factors should be impacting.

ejs
Aspiring Hero
Posts: 5,442
Thanks: 631
Fixes: 25
Registered: ‎10-06-2010

Re: Upload speed killed by interleaving

So what are the line stats from the modem?

It's possible that it's not due to the interleaving, but if you now only get 0.3 Mbps upload then they might have capped your upstream speed to 448k.

edandsuet
Hooked
Posts: 9
Registered: ‎11-08-2017

Re: Upload speed killed by interleaving

I don't know how to make this any clearer.

It's not the speed of 0.3 that is troubling me (although that is also slower than before).

 

It is the complete lack of anything for the initial 6 - 8 seconds.

RealAleMadrid
Aspiring Hero
Posts: 2,713
Thanks: 1,395
Fixes: 59
Registered: ‎07-07-2009

Re: Upload speed killed by interleaving

What speed test are you using? The ThinkBroadband tester give a useful indication of variable speeds.You still haven't posted any Router stats as requested. There could be number of reasons for the initial lack of upload speed such as antivirus issues or some background upload activity going on.

ejs
Aspiring Hero
Posts: 5,442
Thanks: 631
Fixes: 25
Registered: ‎10-06-2010

Re: Upload speed killed by interleaving


@edandsuet wrote:

I don't know how to make this any clearer.

It's not the speed of 0.3 that is troubling me (although that is also slower than before).

 

It is the complete lack of anything for the initial 6 - 8 seconds.


It was clear. I think the "complete lack of anything for the initial 6 - 8 seconds" could be due to the reduced upstream bandwidth if Plusnet have capped the upstream speed to 448k.

Is the problem just with the speedtester, or is it noticeable with other activities?

Gandalf
Community Gaffer
Community Gaffer
Posts: 26,563
Thanks: 10,265
Fixes: 1,599
Registered: ‎21-04-2017

Re: Upload speed killed by interleaving

Sorry to hear you're having problems with your upstream speed


@edandsuet wrote:

I have asked Plusnet to turn interleaving off (as this seems to have caused the upload issue).  They are switching interleaving to automatic, so I hope this will turn it off.


From the notes on your account it looks like we've also placed an order to uncap your upstream speed. Let us know if you still have problems on Monday. We may need to set interleaving to off instead.

From 31st October 2022, I no longer have a regular presence here as I’ve moved on to a new role.
Anoush Mortazavi
Plusnet
edandsuet
Hooked
Posts: 9
Registered: ‎11-08-2017

Re: Upload speed killed by interleaving

Thanks to everyone who replied.

 

Interleaving is now on auto, my ping is back down to 18 ms and the dead upload period has gone away.

 

Thank you for the suggestion to use the Think Broadband speed test.  This showed some interesting results when you looked at the latency analysis.

Whilst interleaving was on, the upload latency was horrible at over 500ms compared to download latency around 100ms.

Now upload and download latency are broadly similar around 100ms.  If anything download latency is slightly lower.