It's not jittery crapsack as you say. That's fine. Also no packet loss. With that pingtest you'll have absolutely no problems with anything.

The 71db line may be better on the pingtest but a few ms jitter will make barely any difference. The terrible speed they have will make things much worse.
The ms pings is down to interleaving. Having a high ping isn't great for gaming but it means lower error build up and less chance of the line dropping out.
Gaming profiles often result in a worse connection due to error build up and plenty of lines will disconnect on a gaming profile, whereas on standard interleaving they would be perfectly stable.

So really ignore that pingtest it's all fine.

Edited by ukhardy07 (Sat 18-Aug-12 23:46:49)

You should be getting the full 20 Mbps without any tweaking. You have an issue if you're having to tweak it down further. How's the setup?

I have seen plenty of Sky lines with a 19, 20 and 21db attenuation achieving the full 20Mbps speed using skys equipment. The issues not across the board that's for sure.
Anything less than 18db should be getting the full speed ideally.

Edited by ukhardy07 (Sat 18-Aug-12 23:54:56)

I'm aware of interleaving etc, I've worked on broadband access networks a fair bit, it's more concerning that on a serialised link like DSL I'm seeing that level of jitter, it should be pretty much zero.

So, yes, 8ms of jitter isn't great given the access technology and the distance between me and the test server, I'd find it more understandable on cable.

In reply to a post by BatBoy:

The line sucks and you're probably on full interleave. The best you can do is ask for a Gaming profile.

I'm not on full interleave, the line may suck but it doesn't suck as badly as those stats suggest as it was happily functioning on a set 18Mb profile with a 7dB SNR margin, suggesting it's Sky's SVBN DLM controlling the output power.

That was exactly what I was looking for confirmation of when I mentioned the SVBN effect, it's Sky's DLM being too clever it would seem.

As I mentioned below when put onto a fixed 18Mb profile briefly I was achieving that with a 7dB SNR margin, which was likely the target margin so it was reducing output power accordingly.

I'll poke Sky on this, selling 'up to' 20Mb and artificially throttling through design or incompetence extracts the urine.

It will be interesting to see if they blame "errors on the line". I had success with them by requesting Gaming mode via their web form even though they responded with the stock excuse. I noticed a much higher upload sync speed over 1Mb when moved to MER rather than always 700k on VC-MUX.

In reply to a post by BatBoy:

It will be interesting to see if they blame "errors on the line". I had success with them by requesting Gaming mode via their web form even though they responded with the stock excuse. I noticed a much higher upload sync speed over 1Mb when moved to MER rather than always 700k on VC-MUX.

Won't wash, managing 18Mb with 7dB margin before their DLM got its mitts on the line then dropping to 16Mb with 6dB doesn't suggest anything other than their dodgy management being to blame.

Seems Sky now set up to 22 Mb via DLM
Here's my previous stats:

ADSL Link Downstream Upstream
Connection Speed 19506 kbps 997 kbps
Line Attenuation 21.0 db 9.5 db
Noise Margin 7.2 db 8.0 db

Then noticed a speed increase looked on Sky and

Testing on your broadband connection began on 26/07/2012 and will be completed within 10 days

ADSL Link Downstream Upstream
Connection Speed 21194 kbps 992 kbps
Line Attenuation 20 db 9 db
Noise Margin 3 db 8 db

Line connection testing completed on 02/08/2012, resulting in the following settings:

Download speed setting
Your connection has been set to a download speed of up to 22.0Mbps .

Upload speed setting
Your connection has been set to an upload speed of up to 1.3Mbps .

In reply to a post by Ignitionnet:

I'll poke Sky on this, selling 'up to' 20Mb and artificially throttling through design or incompetence extracts the urine.

It's not 'artificial.' DLM has capped your line specifically for one reason or another. Most people are not affected much.
DLM has an objective. This objective is NOT to get the best speed. DLM aims to give you a broadband service that will not drop out. This is why lines that have gone via sky DLM will often not have a broadband drop out for months and months on end.

Most lines are fine anyway. Most lines have little error build up and will sync at near enough full speed anyway with DLM. Others get throttled severely like yourself.

It also means that people using an extension socket and a cheap £2 30m white, flat DIY telephone extension also get a broadband service that' totally reliable. Sadly because so many people have incorrect setups DLM has taken this route.

When Sky used to just give whatever speed a 7db noise margin gave, so many people had constant drop outs due to incorrect internal setups. It lost them customers. So here's the solution.
Sadly the more advanced users are a minority. Most people are clueless and when their connection drops out in their extension socket they blame sky & not their setup.

Edited by ukhardy07 (Sun 19-Aug-12 23:38:08)

Just wondering... Do you sync with a 3db SNR or has that just dropped through the day. I've heard that DLM is potentially setting 3db SNR targets now.

It seems that DLM is less strict that what it once was. Although there are still some extreme cases (like this thread).