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Curious Why Plusnets Profile Has Decided To Be Different To BTs?

billnotben
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Curious Why Plusnets Profile Has Decided To Be Different To BTs?

We're only talking a tiny amount here but I'm still curious.
The profile on this connection has been 7.9 for weeks. I've had a couple of deliberate disconnections in that time but always re-connected at 7.9.
Again reconnected four days ago at 7.9 (according to BT) but I see this morning the Plusnet profile has changed to 7.8.
Like I said only a small amount but I'm still curious why the change? Do Plusnet work out their own profiles now regardless of BTs?
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spraxyt
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Re: Curious Why Plusnets Profile Has Decided To Be Different To BTs?

The BT IP Profile might actually be 7896kbps (say) which is printed as 7.90Mbps. However I think the kbps value is probably reported to Plusnet, they round down to the nearest 100kbps which gives 7.8Mbps.
David
Anotherone
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Re: Curious Why Plusnets Profile Has Decided To Be Different To BTs?

If you look at your modem/router stats for your sync speed, you'll see what the exact sync figures are and so how the rounding is working.
On 21CN BT's IP profile is 88.2% of the sync speed, rounded as explained by spraxyt.
billnotben
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Re: Curious Why Plusnets Profile Has Decided To Be Different To BTs?

Quote from: spraxyt
actually be 7896kbps (say) which is printed as 7.90Mbps

That figure is exactly what 88.2% of my current sync speed is so that goes some way to explain things.
Still there was me thinking the profile recorded on BT's test page was set in gold.
billnotben
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Re: Curious Why Plusnets Profile Has Decided To Be Different To BTs?

One more question as you both explained the other one so well.
Is there a similar relationship between "Maximum Bandwidth" and "Bandwidth"? (at the time of reconnection)
Maybe some percent figure the same as between   "Bandwidth" and "Profile" or some set amount related to the "SN Margin".
PeeGee
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Re: Curious Why Plusnets Profile Has Decided To Be Different To BTs?

On my modem/router, the "max rate" seems to change with each refresh. My guess is it the "instantaneous" rate based on the "bits per tone" currently being received or could be received at 100% loading. The "sync" rate is the best stable rate that can be maintained and has spare bits per tone to overcome interference.
Plusnet FTTC (Sep 2014), Essentials (Feb 2013); ADSL (Apr 2009); Customer since Jan 2004 (on 28kb dial-up)
Using a TP-Link Archer VR600 modem-router.
spraxyt
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Re: Curious Why Plusnets Profile Has Decided To Be Different To BTs?

Potentially on a perfect line I suspect the relationship between Maximum Bandwidth and (Actual) Bandwidth at reconnection would be 1 to 1, this implying

  • the target noise margin ratio was met exactly,

  • bits per tone followed an ideal attenuation-based trend, with

  • optimum (whatever that means) allowance for future bit swap activity to cope with "typical" noise.


In the real situation the relationship at reconnection isn't 1 to 1 as I'm sure you'll have noticed. Possibly any difference is a rough indicator of router to exchange connection quality, though I don't know how users might make use of that.
This is basically PeeGee's suggestion interpreted in a different way.
David
Anotherone
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Re: Curious Why Plusnets Profile Has Decided To Be Different To BTs?

It depends on the particular modem/router's firmware, but is generally based on the current bits/tone loading and the current noise margin at sync and is the estimated sync speed for a 6dB margin which is why if your current margin is less than 6dB at sync the "max rate" figure is actually less than the current sync rate Shocked   It's a figure that is pretty meaningless and can be ignored in those circumstances. If you have a higher noise margin than 6dB at sync then the figure gives some indication of what you might achieve if your line was less noisy and/or had less errors.
PeeGee
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Re: Curious Why Plusnets Profile Has Decided To Be Different To BTs?

Interesting - my modem/router (TP-Link TD-8816) obviously works differently as the max rate is currently 3124, sync (Data rate) 2905 and SN margin 2.3dB  Roll_eyes
I don't recall seeing the max rate as low as the sync.
jim:quote
Plusnet FTTC (Sep 2014), Essentials (Feb 2013); ADSL (Apr 2009); Customer since Jan 2004 (on 28kb dial-up)
Using a TP-Link Archer VR600 modem-router.
Anotherone
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Re: Curious Why Plusnets Profile Has Decided To Be Different To BTs?

It could be your firmware is a bit more "clever" then, though that's not much of an increase. It may have looked at bits that could be available if they weren't being swapped (or similar).
PeeGee
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Re: Curious Why Plusnets Profile Has Decided To Be Different To BTs?

Just been following the status changes and the max rate/SN margin seem to have a link, so you are probably right (the manual doesn't reference "max rate"). I have seen a max rate over 4000 with a sync around 3600 but that was before we started having intermittent bursts of noise with phone calls (I hope it's not my peculiar internal wiring!)  Sad
Plusnet FTTC (Sep 2014), Essentials (Feb 2013); ADSL (Apr 2009); Customer since Jan 2004 (on 28kb dial-up)
Using a TP-Link Archer VR600 modem-router.
Anotherone
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Re: Curious Why Plusnets Profile Has Decided To Be Different To BTs?

If it's all CW1308 standard and only terminals 2 & 5 are connected  (Blue+white trace & White+blue trace) at the NTE and all sockets there shouldn't be a problem. All your filters should look like this.
billnotben
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Re: Curious Why Plusnets Profile Has Decided To Be Different To BTs?

Interesting, so that part is quite variable depending on many factors.
On mine the bandwidth is generally 700 or so below the max on reconnection. In the evening the max usually falls 100-200 below the bandwidth figure.
PeeGee
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Re: Curious Why Plusnets Profile Has Decided To Be Different To BTs?

Quote from: Anotherone
If it's all CW1308 standard and only terminals 2 & 5 are connected  (Blue+white trace & White+blue trace) at the NTE and all sockets there shouldn't be a problem. [/url].

The peculiarity is due to the modem/router not being in "the correct place", so there is a joint (using IDC terminals and hidden) near where it should have been  Shocked However, performance is the same (within expected re-sync variations) whether in the test socket/filter or its usual position.
Plusnet FTTC (Sep 2014), Essentials (Feb 2013); ADSL (Apr 2009); Customer since Jan 2004 (on 28kb dial-up)
Using a TP-Link Archer VR600 modem-router.
Anotherone
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Re: Curious Why Plusnets Profile Has Decided To Be Different To BTs?

There is no "the correct place" if your wiring is OK  Wink