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jhbean
Beginner
1,222 Views
Message 1 of 19

Corrupt Downloads

Over a year ago I had sky fibre and started getting corrupt downloads from different sites onto multiple computers. Open reach engineers came several times to try to resolve the issue and could not identify the fault. I then changed to BT infinity but what a surprise, I am still getting corrupt downloads. All of the equipment in my house has been replaced when I foolishly joined BT infinity and I get corrupt downloads if using WiFi or direct Ethernet connection. I DO NOT get corrupt downloads if I connect to a FON WiFi hot spot!

 

I have sent several emails asking for the issue to be looked at without any response from BT. Typical BT support!

 

Comparing a good downloaded file against a corrupt file shows errors with the same 2 bits in a byte. How can this be happening if the packets are protected by a CRC? It is clear that it is a memory fault with the port I am connected.

 

The last engineer stated that a lift and shift cannot be performed because he could not detect the fault. Why is this issue so difficult to resolve?

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18 REPLIES 18
DavidM
Moderator
Moderator
1,104 Views
Message 2 of 19

Re: Corrupt Downloads

Hi jhbean,

 

Welcome and thanks for posting. Sorry you’re having problems. Which sites are you having problems with? Are you seeing any drops in the connection? Give us as much detail as possible and we’ll try to help.

 

Cheers

 

David

 

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jhbean
Beginner
999 Views
Message 3 of 19

Re: Corrupt Downloads

I get corrupt downloads from all sites on all my computers, via wifi ore direct connection. The connection is fast, stable and does not drop out. The larger the file I download the more probable the file will be corrupt. The files at http://www.thinkbroadband.com/download.html all download but when checked with the MD5SUMS, 50% of the time they will not be correct.

 

The corruption is only ever a couple of bits, as seen below from a comparison of a good/bad file containing nvidia drivers.

 

bad.jpg

 

 

 

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marknich
Aspiring Contributor
851 Views
Message 4 of 19

Re: Corrupt Downloads

I started getting this exact same problem with my BT Infinity 2 connection on 9th September 2015. I can browse internet pages successfully but when trying to download any files I am getting corrupt data like you. I've done the same tests as you and notice that there are single bit errors in 2 consecutive 16 byte packets of data. Each time it is the third bit of one of those bytes that has flipped from 0 to 1 or vice versa. My guess is that error correction is picking up most of the corrupt packets but ones where the same bit in 2 consecutive 16 byte chunks is flipped aren't getting detected making the downloaded file corrupt.

 

Did you get a resolution to your problem? After hours on the phone to BT so far with them asking me rubbish like 'is the cable plugged into the wall' I have eventually got an engineer appointment on monday. So far BT haven't been interested in my findings and I don't hold much hope for the engineer having a clue either. If you did get a resolution to this what was it?

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john46
Distinguished Sage
843 Views
Message 5 of 19

Re: Corrupt Downloads

The OP has not been back to the forum since his last post here
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bomb20
Contributor
822 Views
Message 6 of 19

Re: Corrupt Downloads

Look at this thread.

 

 

marknich
Aspiring Contributor
807 Views
Message 7 of 19

Re: Corrupt Downloads

Thank you so much. I live in Prestonpans, East Lothian as well so it's good to know that I'm not the only one having problems. I knew straight away it was a network issue rather than anything in my home but convincing BT of this is impossible - they just have you checking cables and resetting the router for hours on end. You'd think they'd realise that lots of people in the same area were phoning up about the same issue. You'd also expect their service status for the area to say there was fault rather than say everything is working fine. Obviously too much to ask from them.

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velocity
Aspiring Contributor
733 Views
Message 8 of 19

Re: Corrupt Downloads

Same problem here in Haddington East Lothian.

Posted to the linked thread.

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rghaddington
Beginner
704 Views
Message 9 of 19

Re: Corrupt Downloads

Same problem in Haddington. Finally found the problem after this started on 4th September. Glad to see you have confirmed.

 

Totally ignored by BT Customer Care. I am going to the OFCOM/press/bbc Watchdog with this.

 

I downloaded a copy of virtual box from oracle

https://www.virtualbox.org/wiki/Downloads

This is a standard exe

a.exe is downloaded from my neighbours FON connection and installs perfectly

b.exe is download from my Infinity2 connection

Both exes where downloaded on the same machine

I used vbindiff to compare the binary images.

You can see that there is a pattern, a number of btyes are being shifted by 4 decimal (4 hex 100 bin) up on the first byte and down on the second byte.

 

problem.png

 

 

 

 

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rghaddington
Beginner
698 Views
Message 10 of 19

Re: Corrupt Downloads

So the evidence points towards software/hardware on the BT network. The pattern is not noise as it would be random.
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