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Very Slow upload (only certain files)

Help!

Had 350 Mbps service installed at the weekend (should be around 20Mbps up)

Come Monday I got an annoyed wife who says she can't upload files.  She's an editor so spends a lot of time downloading files, editing then uploading them.

So I check it out and sure enough a 150MB file is taking well over an hour to upload or about 0.3 Mbps.  

Now the odd thing, Speedtest.net shows results on-par with what Virgin should deliver.  However m-labs (it's the test that appears if you google "internet speed test") is showing results akin to what I'm actually observing tests seem to split roughly 50/50.

So I totally remove my own router and mesh network, complete reset of the virgin hub, single ethernet connected machine, on a short cat6 etc etc, same results.... uploads to one drive, WeTransfer, google docs, drop box of 150 MB files are really slow.

I get a buddy across the village also on Virgin, but on 200Mbps service to upload a 100MB file to my one drive - all done in around a minute.  I download it (near instantly) and try to upload, after 3 MB in a minute, I give up.  I get the same results on 3 X PC, 1 X Mac, an iPhone and several other devices (I'm 99.999% sure there is nowt up with any of my devices!). To be sure I try the same test on 4G connection with my phone with 68Mbps down and 18 Mbps up) and it uploads in seconds.. So no device issue here.

After a day of calling on and off to virgin, to have reset the hub with them 4 times, to be told it's my antivirus, to oh that's expected behaviour, to it's my wifi, to I need to boot in to safe mode (how do I do that on an iPhone!?). 3 missed calls from supervisors; I'm at my wits end.. They told me I had to raise a complaint because there is no fault and I would need to wait 5-7 days.  Tonight's call passed from one person telling me that the download is about right, to pass me to some tech fix people to be passed back, somewhere on the way, someone booked an engineer!  Let's hope he knows stuff.

I made another test tonight, I put the file from my friend in to a single RAR archive, and the same file in to a RAR archive split at 1MB.  The file split in to 1MB chunks uploaded completely in a matter of seconds.. The single archive was still going after several minutes and hadn't finished.

It's been a while since I looked in to networks in any real detail, but this kind of strikes me as some kind of packet loss and possible retransmissions or restarts, and try be honest I 'm not exactly sure what I'm looking at with Wireshark these days.

Happy to post any info, if anyone has any kind of clue what this could be?

Thanks!

 

 

*Oh I did a bit of sniffing around Speedtest and mlabs - I found Speedtest is downloading 8 X 40. MB files, whereas M-lab seems to only have 4 of varying sizes, ranging from 4KB to 4MB.  The encoding on those files is different, and I'm not sure how many times it's overwriting each etc.

 

 

 

 

 

 

 

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Re: Very Slow upload (only certain files)

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This is typically what I'm seeing - significant numbers of TCP Dup ACK, TCP Fast  Retransmission and TCP Out-Of-Order.

Anyone know how to get Virgin to actually look in to this?

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Re: Very Slow upload (only certain files)

Somehow after about 17 very unhelpful calls to Virgin who told me all these things that basically surmounted to it being a fault with what I was doing, an engineer was booked.

Engineer arrived, and within a couple of minutes he told me "yep I can see a fault".  He showed me a screen in the "Trinity App" which showed I had a very bad SNR for upstream.  To progress he needs a very expensive piece of kit that can test the fibre (image?) and needs to come back another day once he's managed to get said piece of kit.

 

Shame it's not fixed, but glad that someone finally knows what they are talking about.  

I'll continue to update this as things progress in the hopes that it might help someone else down the line.

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Re: Very Slow upload - Dirty Fibre!

The Engineer came back yesterday along with a fibre microscope.  He found right away that the connection was dirty.  He cleaned the fibre somehow and right away upload speed jumped right up.   Now getting over 20Mbps up.  Day to day web browsing has got a lot snappier too (I guess requests were being lost).  Finally Wireshark captures are now pretty clean, with insignificant amounts of Dup ACKs, Retransmissions and TCP Out of orders.

I could never bottom out why Speedtest.net thought that things were fine, but can only guess it sends lots of tiny self contained requests rather than a constant stream of data that needs to stay in order as much as possible.

If you have a problem with speed, I highly recommend you use this speed test tool:

https://speed.measurementlab.net/#/

This tests some distance, so you will see lower speeds than your connection speed, but it tests things somewhat more robustly and is indicative of real world internet usage, rather than Speedtest.net which is a bit like testing endurance by running to the end of the road and back (and is often referred to as a 'last mile test')

N.B. I'm an IT guy, have worked in IT for well over 20 years across most technologies, and been personally doing computer stuff for well over 36 years.  Im not a network engineer, but I understand the basics.  I read through the pinned article, and to be honest that went well above my head, I've no clue about fibre transmission SNR or any of that.  However I could see that there was a real problem, and things were not working.  

Why oh Why Virgin do you use such crap 1st line support?  The engineer had a simple app on his phone that showed right away there was an SNR issue.  Give this to your call centre, and give them some basic training rather than incessantly following "Reboot computer, reset router, use Speedtest.net, not fixed must be a PEBKAC". I spent (really) 11 phone calls and at least 14 Virgin staff, several hours, and several wasted tests that could have been tested in the first few seconds of me calling.

Give your engineers, and installers the kit to test lines when they instal them, yes it might be expensive kit, but you've just had an engineer visit twice, have to speak to his manager, borrow a device from another engineer, probably wasting a day of effort all told, which is going to have paid for the microscope, and have given me a good experience rather than this shockingly bad one.

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