Ask the poster, not me.

broadband66

See my post above

In reply to a post by broadband66:

"Nobody is currently selling this."

Are we saying that all this is just speculation then? Best guess?

No. We know the details on how VOIP will be delivered.
The low bandwidth broadband tier (0.5/0.5Mb/s) from Openreach already exists and we know the pricing.
The telephone USO hasn't changed and AFAIK isn't changing in the immediate future.

It's just pointless calling a provider asking for details as they aren't selling the product yet.
Margaret from BT customer services isn't going to have done the reading up on the subject that many members of this forum have.

Even when a provider is selling it I doubt they would know any of the detail being asked.
I would be utterly gobsmscked if any of the BT sales staff knew the inner workings of the SOGEA product they already sell other than you plug the phone in to the router.

In reply to a post by kitcat:

OR offer a 128Kb service which is what BT will use to provide BTVoice. There will be no ability to use it as a BB connection.

In reply to a post by j0hn83:

No. We know the details on how VOIP will be delivered.
The low bandwidth broadband tier (0.5/0.5Mb/s) from Openreach already exists and we know the pricing.

So which is it likely to be for SOTAP then chaps?

Openreach are delayed on getting the spec. finalised for SOTAP. Any inkling of the holdup? Seems pretty straightforward by all accounts 😀

[128Kbps is plenty for a single voice channel using a half decent codec…]

Even using G.711 you are only looking at 80kbps including the IP overheads.

I don't recall ADSL supporting limits in the same way as FTTC does, and historically the rate adaptive service performed better than the fixed rate (512k/288k, 1M/288k or 2M/288k) offerings on very long lines. The delay in releasing the SOTAP product may in some part be working out how to limit the rate adaptive service for a voice-over-IP only offering.

In reply to a post by tdw42:

I don't recall ADSL supporting limits in the same way as FTTC does

The ADSL spec doesn't need to support it.

The 0.5Mb/s service on FTTC uses the same profile 17a as all the other FTTC tiers. The way product limits are done on FTTC (40/55/80Mb) is just the DLM setting an upper limit.

IMO they will likely do the same on the ADSL version (SOTAP).
The modem would be free to choose the tones it wants like the rate adaptive ADSL we currently have but with an upper limit/cap on sync speed.

I think it's very unlikely they will do SOTAP with 20CN style fixed rate profiles.
The lowest fixed rate was 0.5Mb. If a line couldn't manage that it either wouldn't sync or would drop packets when SNRM dipped.
If they use rate adaptive ADSL with a very low sync speed it should be stable on those longer lines. There's no reason an ADSL DLM couldn't be made to do that.
I think the ADSL DLM can do/does banding/capping to some extent already.

SOTAP is very much up in the air though and it's anyone's guess how they will end up implementing it.

In reply to a post by j0hn83:

The ADSL spec doesn't need to support it.

I was imprecise. I wasn't thinking of the G.992.x specifications, more the Openreach and/or BT Wholesale line management implementation.

There's no reason an ADSL DLM couldn't be made to do that.
I think the ADSL DLM can do/does banding/capping to some extent already.

Indeed, it depends on what functionality exists. AFAIK ADSL and FTTC have banding to cope with bad lines, and whilst FTTC has a number of open profiles (0.128-80M/0.128-20M for the 80/20 product, 0.128-40M/0.128-10M for the 40/10 product, etc.) I am not aware of ADSL having anything similar where the CP can request an open profile with the maximum not being sync rate (minus protocol overheads, obviously).

Will Openreach actually provide any more than the copper loop for SOTAP?

This intro / briefing note implies they won’t necessarily…talks about “LLU exchange infrastructure”

Will the necessary DSLAM and CPE specification and provision for SOTAP actually be in the hands of BTW (and perhaps some CPs that will provide their own SOTAP based voice provision)?

Are BT Wholesale, rather than Openreach, then effectively driving the SOTAP bus (ADSL based in specification)? I know this may be semantics to some as it’s seen as “all BT anyway”.