TR101?

I've been steady at a bras profile of 7150 since Sept 2011, and now in the last couple of days have changed to "TR101" when I look at my line data. Never seen this before - what does it mean?

1144 7682 8708 TR101 Auto 18-Dec-2011 07:42
1144 7682 8708 TR101 Auto 16-Dec-2011 04:18
1137 7150 8128 adsl7150 Auto 16-Sep-2011 06:55

You've been switched from 20CN IPStream to 21CN WBC.

What is your ADSL Mode (G.DMT or ADSL2+) at the router?

>>Your current line technology is WBMC

I've been on 21CN since May 2011. I've been contiuously sync'd since Sept @ 8128 with a bras profile of adsl7150; my router is operating in ADSL2+ mode and has been connected at 1144 / 8709 kbps since Sept, but for some reason two days ago the profile changed to TR101 and the line stats now read as sync'd at 8708).

It is a new way of calculating profile on 21CN lines based on your current sync speed x 88% I believe.

A line I manage (sadly not my own) has this from the last few days

1240 20292 22999 TR101 Auto 17-Dec-2011 03:22 17-Dec-2011 03:22
1240 20292 22999 TR101 Auto 15-Dec-2011 08:17 15-Dec-2011 08:17

WBMC is indistinguishable from WBC as far as user is concerned. Depends on how ISP has provisioned its pick up from BT which we can't see.

You were probably on a G.DMT profile, over WBC, from May then until now.

Edited by XRaySpeX (Sun 18-Dec-11 18:53:30)

Mine says TR101 dated from 12th.

Hi,

The TR101 is the result of a recent change to how BRAS profiles work on 21CN, which BT's data to us has now started reflecting.

If you see this in the 'BRAS profile' column then it means your BRAS profile will automatically track your sync rate - and be set at 88.2% of it. The 'Downstream' column in the Line Rate Data column is what your BRAS profile will be set to.

In your case this means you've got a slightly faster connection, as you're no longer stuck to the BRAS profile of 7150, which was the maximum for an up to 8 Mbit/s service.

ta,
Phil.

A recent systems release from BT Wholesale as made this change visible to you through the information we receive from them on your line.

Very simply it means for 21CN (WBC/WBMC) services only the BRAS is calculated instantly based on your sync rate and not based on the old profile change to match system. Read the 2nd column not the 4th

If your interested in the reason it�s called TR-101:

http://www.broadband-forum.org/technical/download/TR...

Please be aware BTW will have implemented components of this standard and not all parts and it is suggested standard not a definitive way of doing a set task.

I'm new to Zen within the last month having been with BT Intranet for many years - most of them good and stable with the occasional hair tearing incidents. I switched on Which's recommendation.

This is interesting. My BRAS was set at TR101 on 12 December but on the same day, my downstream dropped forma quoted 4000 [between 3991 & 4005] and since then has been showing at 2702. My sync rate went down to 3064 from 4540.

Is BT up to mischief and trying to restrict my speed?

Why is it fixed at 88% of sync speed? Why not 98% or 92% or whatever?

Because allowance needs to be made for Layer 2 overheads.
The line rate (sync speed) is a Layer 2 bit rate. The profile is a Layer 3 IP rate.
IP packets are encapsulated within a Layer 2 frame/cell before being sent to line, with the extra data needed being the 'overhead'.

A 12% (ish) overhead is assumed for typical traffic.

Search for 'OSI model' for more information.

Also interesting that since TR101 first appeared under "BRAS Profile" for my "Line Rate Data" in the Portal on 15 December, a new row of data has appeared in the morning of alternate days - even though the numbers themselves are the same each time. So it seems that, whereas previously there was only a new entry whenever something changed, now there's a new entry every other day.

p