Profile Steps

I had 38717 profile for months before a sudden step down to around 339xx/340xx and another down to 328xx

Tonight after 7 months I have seen a sudden recovery, although no loss of sync registered and I am back at 38716 ! Who knows why?

Are there defined major profile steps or is it really as fine as 1kbps?

I beleive it could well be as fine as 1kbps steps.

Your history sounds simular to mine. 38717 for the first 8 months, then 5 Mb drop with fluxuating profile for 5 months untill 17a kicked in and gave me back 38716.

These are all the profiles I've seen during that 5 month wobbly period. The smallest gap between consecutive profile changes was 9kbps.

33566
33730
33827
33836
33865
34532
34933
36628
37585
37616
38173
38716
38717

It's roughly 88% of sync, so even if there are steps they are very small and can be disregarded.

If you are sure there has been no re-sync I wonder if it could be that the DLM does after a long time sort out a jump needed by an long-term higher sync? I think we have evidence in earlier posts that people who have had faults fixed have needed the engineer fixing it to call for a reset on the line, otherwise speed is not regained. Maybe your sync should have been delivering higher for ages?

It has had a couple of deliberate power cycles recently and also an engineer requested line reset - which resulted in a 20k drop! So it seems to have been delivering to a limit.

Maybe there has been a soft resync ... and maybe I have gone to 17a but until I can flash te modem I will not know.

In reply to a post by MHC:

It has had a couple of deliberate power cycles recently and also an engineer requested line reset - which resulted in a 20k drop! So it seems to have been delivering to a limit.

Maybe there has been a soft resync ... and maybe I have gone to 17a but until I can flash te modem I will not know.

It appears that the FTTC connection is able to resync "on the fly". i.e. dynamically allocated IP addresses are maintained, your ISP doesn't see the event in their log file, but a substantial change in sync speed & thus profile can be observed by the end user.

In reply to a post by Bald_Eagle1:

It appears that the FTTC connection is able to resync "on the fly". i.e. dynamically allocated IP addresses are maintained

That happened to me recently. There is a technical term but I can't remember it atm.

You referring to Seamless rate adaption?

Yes that's the one.

Hmm

VDSL2 adopts a number of improvements to better tackle the various bandwidth needs of different operators.

For example, VDSL2 supports improved impulse noise protection (INP), impulse noise monitoring (INM), SRA, U0 PSD (power spectral density) shaping, and new service and initialization policies for enhanced triple play stability. Other advanced technologies such as emergency rate reduction (SOS), dynamic rate repartitioning (DRR), and crosstalk channel estimation and mitigation techniques are also being proposed in the standard.

But Openreach is the operator, so the question is what have they implemented.

Don't forget SRA is supported on ADSL2+.