In reply to a post by wolvesmad:

I don't like how the DLM caps the sync speed, so to speak.

I totally agree, for almost all poor lines setting a target margin of 15 dB will keep it stable. Setting the target noise margin is a more elegant solution, which is why pretty much every other ISP does it that way.

For poor lines, the DLM synch caps can be vicious, caps of a few 100 kbps on lines supporting a couple of meg are not uncommon.

And just to add, even a 6 dB margin is adequate for poor lines in many cases. Take this example:

- line synchs to 6 dB target margin while the line is "quiet"
- noise causes line to drop, line resynchs at a "noisy" 6 dB margin
- line conditions improve, noise margin jumps to 15 dB with no further loss of synch

So the line sits at a noise margin of 15 dB even though the target margin is set to 6 dB, which gives plenty of spare margin to mitigate another noise event.

Setting hard synch caps completely removes the "elegance" of this behaviour.

I get around 6500 but that's with me forcing the line to ADSL2 on a 3db SNR.

If the line switches to ADSL2+ it tumbles down to around 4500 due to the night time drop outs.

The fact I can't force the modulation mode on Sky means I will probably give them a miss until the area gets fiber.