Fibre sync vs. IP profile

[#1]

Having been on the 80/20 trial, I've just moved to the new Fibre Extra package to continue the faster speeds and increased usage allowance.
I've noticed something odd.  In "High Speed Broadband" in the member centre, it now lists my Line Speed as 78Mb, and says that this is based on the sync speed of the line.  However, when I run the BT Speedtester, it reports that my IP profile is 68Mb, and it's been at that value for a while.  I know that the IP profile is always a little below the sync speed, but I think a 10Mb difference is quite big.  Any ideas what could be causing this, and what I can do to fix it?  I wonder if PN could put my line back into training, now that it's stable on the 80/20 service?
Gary

[#2]

I think that the 78Mb is the default now that they have stopped using the generic 20Mb (effectively unrestricted) and it will only change once they get a new Delta Report
Note that what Plusnet refer to as Line Speed is a mirror of the IP profile

[#3]

Because the FTTC modem can resync very quickly it's possible for the BT profile to be wrong as it doesn't realise the line has even been dropped (your router may also not realise for the samne reason), if you manually disconnect and reconnect the router (NOT the modem) then the profiles should update to your current sync (if they're not already).
The sync is near enough 103% of the BT profile (when the profile is correct) so 68Mb profile would indicate a sync at 70Mb, not sure whether the Plusnet profiles are currently following the BT ones and, if so, how long it takes.

[#4]

Thanks.  I've restarted the router (leaving it off for a few minutes, then powering back up), but still got the same IP profile.  The Plusnet site still says my line speed is 78Mb.
Thing is, when my 80/20 was first activated I had 75Mb/sec, and then because of a problem on the trial, the speed dropped.  Now that the problem has gone, I wouldn't be surprised if my sync speed is 78Mb, but the IP profile is stuck too low.
Could interleaving being on cause such a drastic drop?  If so, would asking Plusnet to put my line back into training solve that (assuming it's stuck, and the current speed isn't really the maximum the line will support)?

[#5]

Quote from: garywood84

Could interleaving being on cause such a drastic drop?  If so, would asking Plusnet to put my line back into training solve that (assuming it's stuck, and the current speed isn't really the maximum the line will support)?

Yes, it can and it does - typically around 8Mbps for me when it's on (it's currently off and has been for a week - longest ever). I do not believe Plusnet has the ability to request a DLM reset.

[#6]

Thanks, Kevin.  I've had a debate about something related with Plusnet before.  My line is currently on the "Standard" DLM profile, but I'd like to be on the "Speed" profile (interleaving off) that BT offers (alongside a third option, "Stable", for which interleaving is always on).  Plusnet insists it can't change this, but BT says it's possible for ISPs to do so!  And, I noticed when I changed to the new Extra package that the internal ticket that was raised mentioned 80/20 fibre "standard stability".

[#7]

Yes, I remember that debate, which was never properly resolved.

[#8]

I've got a ticket open at the moment about the difference between my line speed and IP profile, so I'll see how that resolves, and then I might raise this question again.

[#9]

From what I've read everywhere at present it seems that there is no option for anyone to manually turn interleaving off or on with a FTTC fibre supply.
It seems the DLM/DSALM will decide this by itself as an when it likes as the line conditions vary.
This is not to say this is who it will be for ever - the option might be well be provided in the future.

[#10]

Thanks, x47c. I think you're right that there's no way to specifically turn off interleaving: DLM/DSLAM controls this automatically. However, as I understand it, there are three available DLM profiles, that can control what the DSLAM does, including "speed", which has interleaving set to fast path.