Value on 21CN

[#1]

@MisterW
Which was what I expected but moving to the new card etc. in the exchange appears to have improved my line significantly and increased the default noise margin from 9dB to 12dB
@purleigh
I understand that 21CN and ADSL2 are two separate things.
21CN gives the cost saving to Plusnet but under 21CN you can have ADSL, ADSL2 and ADSL2+ and that doesn't change the costings

[#2]

Quote

BUT to have his Value account line profile limited to a maximum of 8000Kbps (as if it were still on an ADSL1 connection).

@purleigh,
Not quite correct, ADSL1 is the modulation type, normally reported as G.DMT (G.992.1 ) and allows sync speeds upto 8Mb, ADSL2 ( G.992.3 ) will allow up to 12Mb  and ADSL2+ (G.992.5) upto 24Mb. On 20CN the only mode was ADSL1, on 21CN all the modes are possible but Value acoounts are limited to ADSL1 mode. The cost saving to PlusNet still applies since the connection is now on 21CN.
Edit : looks like Jim beat me to the explanation
@OldJim, How does your connection speed compare to previously ?

[#3]

OK, I appreciate the technical differences between the modulation types, but I was looking at this from the point of view that it probably costs Plusnet the same for whichever modulation is selected as it is merely the line setting between the exchange and the home router.  BUT I would hope that it is in Plusnet's interests to get the best available performance for each customers connection, and therefore even on Oldjim's 50dB cable, a quick estimated linespeed check on Kitz shows that his IP profile is likely to improve by changing up from ADSL1.  I would expect that almost all customers would be appreciative of a step up in IP profile, assuming that stability does not suffer as a result.

[#4]

No I wouldn't.
Changing to ADSL2 means I could hit the banded profile problem - there is no way I want to risk that

[#5]

Fair enough,
it will be interesting if you get any better stability
[quote=Oldjim]... on my somewhat dodgy line

[#6]

Current stats - after one forced resync in daylight to get the speed up a bit
Now waiting to see how long before the training period does something
Edit - ignore the error secs as that doesn't reset unless I reboot the router

[#7]

Now at over 8 days and no problems and no resyncs
Note that the supposed 10 day training period appears to be doing nothing at all.
I am beginning to think it only does something if there is instability - note that the old settings (interleave and default noise margin) were carried over

[#8]

Quote

Now at over 8 days and no problems and no resyncs

That's good news Jim

[#9]

20CN had a specific 10 day training period, but this is a little more fluid on 21CN. If your line has remained stable at a good SnR margin then no modifications will be required so you will see a stable connection.

[#10]

In my case - good means far too high

[#11]

Update - 24 hours ago I forced the noise margin down to 6.9dB (the lowest it will go) and this is the result - again ignore the error seconds as they don't get reset without a router reboot

[#12]

4256kbps on a 52dB line is better than expected, but you may see some drops due to forcing the SNR margin.

[#13]

When I first went onto 21CN the reported attenuation dropped from 52dB to 50dB so I assume the current reported level of 51dB is somewhere between 50.5 and 51dB depending on how the rounding process works.
The noise margin variation overnight is very good so I would be surprised if I get serious problems although there could be a mess if the automatic systems decide to drop the default noise margin.
After a couple of days I will have another fiddle to drop the speed down to just over 4000kbps which will keep the 3,500 IP profile (it hasn't changed yet and I don't expect it will for another few days)
Note that the noise margin rose to a higher level this morning which I assume is due to the bit swapping which happened over night

[#14]

Sounds good to me, let us know how it goes

[#15]

After over 2 days with no problems I did a bit of fiddling with DMT and increased the default noise margin to about 9dB with a sync speed of 4,000kbps which will maintain an IP profile of 3500kbps.
I will now stop fiddling and wait for the automatic systems to do something.