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BT 'banded profile' - crude form of capping

« on 23/06/2009, 10:15 »
I mentioned this in a recent reply to another question, but it probably deserves its own topic as it's of more general interest.

If you're having problems with your line (line dropping, high error rates, etc.) you might be put on a 'banded profile' - i.e. have your downstream sync speed capped - by BT. I'm currently banded, with my sync speed being capped at 3069. I've just recently learned from a PN faults team member that the banding is a very crude instrument. The bands run in 3mb/s increments: 0-3mb/s, 3-6, 6-9, etc.

I've seen a couple of other people wondering why they were always syncing at a low figure of 3067-3070 for long periods, and I suspect they may be in the same position (especially if their SNR is high - mine is currently around 15). You'll probably need to raise a ticket if you want confirmation that you've been 'banded'. I'm not sure if banding is removed automatically if your line has been stable for a long time - mine was removed a couple of times after PN intervention, but was automatically reinstated a few days later. If you're syncing at around 3070, your 'current line speed' as reported on PN's 'high-speed broadband' page will be 2500.

That's the general point. Experts - please say if I've got anything wrong. I'm not sure what the exact sync speeds of the higher bands are. Feel free to stop reading here, because the rest of this post is just about my own situation.

This crude banding is disappointing for me, because I reckon my line would currently support a sync speed of around 4500 and remain stable, whereas if it syncs at its unbanded maximum (around 5200) the line becomes unstable at night. So I asked if I could have a 4500 cap, but I was told that's not how it works.

In the course of working all this out (I had an open ticket for over a month) I learned several things:

- Often, and understandably, communication between the different areas of PlusNet isn't optimal - I had to keep explaining the same things to different people, even though what I was explaining was all there in the ticket history. The general support team and the faults team don't always communicate. This is not a big criticism - PN staff all have a lot to do in a short space of time, and they're way better than support elsewhere. Just be patient and keep explaining.

- Also, I learned that it's pretty much impossible to get PN to test a line at night. My line was tested several times, but always during office hours, when there was no problem with decreasing SNR and instability. Again, I can understand why this is, but it was disappointing.

- Finally I learned that my line could become unusable (SNR =  -2, WAN IP address reported as, PPPoA state being 'LCP Up' instead of 'Up', router reporting that the ADSL line was being restarted every 60 seconds) without anything being visible at the PN/BT end. I don't know if that's an issue relating to PN's monitoring system or just the way ADSL works.

I've come to the conclusion that my speed is being limited by two separate factors. The wiring in my house means that I can't get more than about 5200 downstream sync (with an attenuation rate of 39db I should be getting 6000+), and in addition something external to my house (street lighting is my best guess) means that my fastest rate is not stable after sunset.

I've decided to live with it, at least until fibre-to-the-cabinet is offered in my area, at which point I'll have my house rewired. My downstream speed with ADSL2+ is now about the same as it was before, and my upstream speed has almost doubled, so I haven't lost anything and, unlike some, I do have a working connection. Thanks to everyone at PN who helped to process my ticket.

Link to Plusnet profile (aka "Current Line Speed" - no longer visible from 'Connection Settings'):
« Reply #1 on 23/06/2009, 10:59 »
intersting cheers for that post graham
ive had stuck 3070
 an allso 4544 which is the top end of my snyc rate so dont know what was going on with fixing my sync so high as that was causing more errors on my fastpath line that i liked
each time my sync has unstuck its self after say a week dont know if PN had any thing to do with that as posted about it but didnt ticket about it. since these 2 fixed syncs ive not had them again which is couple of months by now

« Last Edit: 23/06/2009, 11:04 by ASBO DOG »

« Reply #2 on 23/06/2009, 11:12 »
yeah very interesting, the 3-6-9 capped mb/s rules does need to be changed, my sync has been 3070 for a couple months and on adsl i had syncs of around 5mbs......
« Reply #3 on 23/06/2009, 18:08 »
Interesting information there.

I had/have the same problem too - had banding removed and now it looks like it is back.  My sync is 3750 @ 15db.  Been like this for over a week.

I'm off on holiday is a weeks time for a week - on my return if things have not improved - will on 21CN for 4 months then.  Time to migrate.  I've completed my moves of my main domain names/email to a external company.

Will be a shame - been with PN from the dialup days - the days when PN was only a small company.  Cry

« Reply #4 on 24/06/2009, 17:02 »
Hi Phil,

If you're seeing worse speeds on ADSL2+ than you were previously, I'd quite like to try you on the ADSL1 variant of WBMC.

It should give what you were experiencing previously.
« Reply #5 on 24/06/2009, 18:10 »
Thats not what he is saying, hes notifiying people like me to an issuse that BT are using a rubbish form of line managment - you should be providing the 100% proff about the practice and not asking if he would like a degraded product.

[Moderator's note by Adie (dvorak):  Full quote of preceding post removed, as per Forum Rule]

« Last Edit: 24/06/2009, 19:52 by adiewoo »

« Reply #6 on 24/06/2009, 20:26 »
Hi James

I've been offered this already so far not take PN up on the offer - as the will mean a max of 448kbps upstream - I like the faster up speed too.

  • dave
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« Reply #7 on 25/06/2009, 18:22 »
We have the choice of the following

ADSL2+ with 448 up
ADSL with 448 up
ADSL2+ with uncapped up
ADSL with uncapped up

So we can switch to ADSL with uncapped upstream although I don't know if the maximum upstream on ADSL is lower than the maximum on ADSL2+, if you get over 900kbps now it may go down to 832kbps.

It's 1 working day to change and 1 working day to change back if needs be.
Dave Tomlinson
PlusNet Network Services
« Reply #8 on 25/06/2009, 18:29 »
Hi Dave

Thanks for the information.   Like the sound of "ADSL with uncapped up"  - also my current up speed is 856kbps.  so the max of 832kbps is not a big lose.

« Reply #9 on 28/06/2009, 08:50 »

  Deleted in favour of own topic ADSL2 to ADSL

« Last Edit: 28/06/2009, 09:16 by mjtuohy »

« Reply #10 on 13/07/2009, 13:53 »
haha been stuck at 3072 at 15db noise for 2 weeks due to thunder storms awhile ago, any one want to guess what DLM thought would be the best thing to try next?

 Grin 4554 at 9db and thats fixed a sync.  is the DLM of its head why not try 12db on a varibale sync rate before pushing the line to the max of its limits
« Reply #11 on 13/07/2009, 15:37 »
Last week mine went from 15db with an interleave depth of 16 to 6db with an interleave depth of 120. After a few hours my IP profile went up to an all time high of 4000kbps. Unfortunately it did not stay that why for long and after a few resyncs at different values I'm currently at 12db with an interleaved depth of 16 and a 2000kbps IP profile.
« Reply #12 on 14/07/2009, 16:40 »
hi i think i have a problem with my sync rate to. It has been stuck on 6655kps for nearly 4 weeks now and it does not change regardless of change to my snr. i was on 12 now 9db and the sync is exactly 6655kps. So does this mean i have a banned profile?
« Reply #13 on 15/07/2009, 16:39 »
I'm not sure. From the information given to me when I was in contact with the PN faults team I reckon your sync speed looks a bit high to be banded - I would have thought somewhere around 6140 would be the next band up from mine. However, I don't really know what the precise banding speeds are, apart from the one I'm in, which is 3070 give or take a couple of kb.

Could anyone, either working for PN or not, have a go at explaining exactly how the banding works and what the bands are?

Link to Plusnet profile (aka "Current Line Speed" - no longer visible from 'Connection Settings'):
« Reply #14 on 17/07/2009, 12:40 »
Could anyone, either working for PN or not, have a go at explaining exactly how the banding works and what the bands are?

yeah i would like an offical detailed explantion of how branding works please.

ive gone from fixed 3072 on 15db to 4554 on 9db and now back after a few days to 3072 on 18db. why does the system not try 12db on a varable sync before going mad and going from a low extreme to high extreme. esp as i am running fastpath you would think they would of programed the DLM  to be very careful what it does on fastpath lines
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