Interesting. I didn't realise you'd been testing quite that much.

Some questions...
- Did they fix your problem in the end? Was it physical?
- Did you do these tests after the fault was fixed, or as part of the investigation?
- Do you have graphs to show the different bit-loading patterns?

It certainly suggests that there is a case for allowing people to self-cap the upstream, in order to improve the downstream.

In reply to a post by BatBoy:

But 40/10 to 80/20 had no effect?

That's right.

My connection is unable to use any of the higher frequencies needed for up to 80/20, so it was already using everything it could on 40/10.
Therefore no difference was seen by attempting 80/20.

In reply to a post by WWWombat:

Interesting. I didn't realise you'd been testing quite that much.

Some questions...
- Did they fix your problem in the end? Was it physical?

Yes. Fluctuating SNRM & disconnections from using the phone turned out to be a defective faceplate filter & all the other random disconnections (especially during warm & dry weather) turned out to be a poor underground cable to pole top DP joint.
The DP joint actually fell apart as soon as the engineer touched it

- Did you do these tests after the fault was fixed, or as part of the investigation?

SOME testing was done during the investigation (mainly as Plusnet's experimental attempt to induce a DLM reset without engineer intervention - it didn't reset DLM).

The same pattern was seen, but as my connection was so unstable at that time, I discount the data as unreliable.

- Do you have graphs to show the different bit-loading patterns?

I have so many graphs, without literally spending hours on it, it would be difficult to pick out the most relevant.
Here are a couple though:-

2Mb Capped US

Up to 10Mb US

The differences are slight, but visible.

Not really relevant to this topic, but the change from 8c to 17a also had some effect on lower speed connections.

Mine, for example, could use all the 8a DS frequencies (up to tone 1627).
However, it cannot use all the 17a DS frequencies due to attenuation over distance from the cab.
The highest tone it can use is approx 1750 (approx 7.5MHz).

Some connections that could use slightly higher frequencies up to say tone 1963 benefited more from the switch than others.
Mine only benefited slightly from the increase from DS tone 687 to 859 & lost a little as the next tone band now also starts at a slightly higher frequency.

8c DS tones - (32,687) (1192,1627)
17a DS tones - (32-859) (1216-1963) (2792-3959)

THose are from a Huawei DSLAM. ECI DSLAMS are slightly different on 17a & I have no idea what they were on 8c.

It certainly suggests that there is a case for allowing people to self-cap the upstream, in order to improve the downstream.

The difference isn't great, but a slightly higher US speed does more than offset the lowered DS speed for my own useage - working from home quite a lot & needing to upload data to the office servers.


EDIT:
Hmmm. I wonder what effects would be seen for someone who can't max out 80/20 experimenting with 80/10 and/or 80/2.

Any takers?

Edited by deleted (Sun 30-Sep-12 09:08:53)