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In case anyone hadn't noticed it's official tha BT are upgrading to Profile 17a - sadly I think that they are going to keep on Band Plan 997 which is a bit of a pain on mid-length lines.
Checked the modem this morning - "attainable" now up to ~49000 Kbs -1, sync at 39999 Kbs -1. It had settled to ~37000 Kbs -1 recently on 8c (apart from an odd week where it held 40M but at a 3dB margin following an overnight resync - I did wonder whether the DLM would set a 3dB margin but no dice; it reverted to 6dB at the next resync).
Here's the odd thing though - my U/S attainable has fallen from ~17Mbs -1 to 11 or so. Given that the 17a adds an upstream block first (from 7.05MHz to 12MHz) I had expected to see U/S well above 20M.
Must get some graphs and have a look what's going on but in the meantime anyone have any ideas?
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In case anyone hadn't noticed it's official tha BT are upgrading to Profile 17a - sadly I think that they are going to keep on Band Plan 997 which is a bit of a pain on mid-length lines.
They are moving to Band Plan 998
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
M H C
taurus excreta cerebrum vincit
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They are moving to Band Plan 998
OK, have telnetted in had a closer look and dug out the old stats - you are, indeed, correct. [edit] Oh, and I can see that this has already been discussed on the "Strange speed increase" thread - apologies for not keeping up 
I now get
xdslcmd info --pbParams
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Max: Upstream rate = 11817 Kbps, Downstream rate = 49388 Kbps
Path: 0, Upstream rate = 10000 Kbps, Downstream rate = 39997 Kbps
Discovery Phase (Initial) Band Plan
US: (0,95) (868,1207) (1972,2783)
DS: (32,859) (1216,1963) (2792,3939)
Medley Phase (Final) Band Plan
US: (0,95) (868,1207) (1972,2783)
DS: (32,859) (1216,1963) (2792,3939)
VDSL Port Details Upstream Downstream
Attainable Net Data Rate: 11817 kbps 49388 kbps
Actual Aggregate Tx Power: 6.5 dBm 12.6 dBm
============================================================================
VDSL Band Status U0 U1 U2 U3 D1 D2 D3
Line Attenuation(dB): 6.5 33.2 48.3 N/A 16.2 40.3 61.4
Signal Attenuation(dB): 9.5 32.3 47.2 N/A 16.2 40.3 61.4
SNR Margin(dB): 8.0 8.1 8.1 N/A 10.3 10.4 0.0
TX Power(dBm): -4.4 -11.8 6.1 N/A 10.7 7.9 -128.0
It looks to have given up on D3 altogether given the 61.4dB attenuation so basically I'm just benefiting from the fact that the D2 tones now go from 1216 to 1973 compared to 1192-1627 previously. I remain slightly surprised that U/S attainable hasn't improved given that U2 should now come into play (albeit at 48dB attenuation)
It's a good move on my line - gives me back max sync and some overhead against crosstalk. Not much point me going for 80/20* but I'm happy at 40/10 compared with 3Mbs -1 on ADSL.
*might have done if the U/S had improved even if the D/S didn't change much.
Edited by mr_bean (Thu 10-Nov-11 10:43:49)
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Just had a look at your original link - and it is conformed in there too.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
M H C
taurus excreta cerebrum vincit
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Interesting results. What distance are you from the cabinet?
My line is similar, and has gained 2-4Mbps in Downstream speed since (I think) they introduced 17a, but has retained the full uplink speed. I'm about 600-650m from the cabinet.
From your modem stats, I'd guess you have a little room to go beyond 40Mbps. It looks like it has chosen to distribute the required 40Mbps to give an SNR of 10dB. It could well be that some of D3 would get used if it needed to push the SNR down to 6dB, while both D1 and D2 seem to have 4 dB's capacity left.
I think I need to unlock my modem too, and find the detailed figures 
On the ANFP: it has a history indicating:
- Issue 5 (V5.1.0)
- September 2011
- Revised to accommodate plan VDSL2 998ADE17 and include frequencies up to 17MHz. VDSL2 profile 997-M1c-A-7 8c is deprecated.
I also remember an old BT document (2009, when they first played with VDSL2) stating that it is impossible to run both plan 997 and 998 within the same plant, because of interference problems.
Taken together, I suspect that means the entire FTTC deployment will shift to 998+17A, with nothing left on the 997 band.
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Interesting results. What distance are you from the cabinet? Approx 600-650m (it's 560m in a straight line so not less than that).
FTTC since April - original sync 39997, attainable 42M ish (from engineer's JDSU). Stayed that way for a while (initial figures from unlocking the modem very similar) but then I seemed to acquire a 3dB noise increase - oddly coincidental with the original modem dying but I still presume it must have been increased crosstalk.
From your modem stats, I'd guess you have a little room to go beyond 40Mbps. It looks like it has chosen to distribute the required 40Mbps to give an SNR of 10dB. It could well be that some of D3 would get used if it needed to push the SNR down to 6dB, while both D1 and D2 seem to have 4 dB's capacity left. Attainable 48M at the moment which from observation is at a 6dB SNRM. I wonder if there is anything extractable from D3 - my ADSL line managed 3Mbs -1 on 63dB attenuation but I'm not sure you can draw any conclusions from that.
I also remember an old BT document (...) stating that it is impossible to run both plan 997 and 998 within the same plant, because of interference problems. I'd certainly expect it to be impossible - upstream and downstream bands overlap between the two band plans. That would mean modems in one band plan transmitting on frequencies that modems on the other band plan would be trying to receive - the near end crosstalk would be huge.
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your line looks very similar too mine
# xdslcmd info --pbParams
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Max: Upstream rate = 12014 Kbps, Downstream rate = 50444 Kbps
Path: 0, Upstream rate = 10000 Kbps, Downstream rate = 39996 Kbps
Discovery Phase (Initial) Band Plan
US: (0,95) (868,1207) (1972,2783)
DS: (32,859) (1216,1963) (2792,3939)
Medley Phase (Final) Band Plan
US: (0,95) (868,1207) (1972,2783)
DS: (32,859) (1216,1963) (2792,3939)
VDSL Port Details Upstream Downstream
Attainable Net Data Rate: 12014 kbps 50444 kbps
Actual Aggregate Tx Power: 6.6 dBm 11.8 dBm
============================================================================
VDSL Band Status U0 U1 U2 U3 D1 D2 D3
Line Attenuation(dB): 5.6 31.4 45.9 N/A 15.3 38.9 59.7
Signal Attenuation(dB): 7.3 30.6 44.7 N/A 15.3 38.9 59.7
SNR Margin(dB): 7.7 7.7 7.7 N/A 7.0 7.1 7.4
TX Power(dBm): -3.9 -13.3 6.3 N/A 8.1 7.9 4.3
thing is it used to only sync at approx 30000kbps downstream and 8000kbps up
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I think I need to unlock my modem too, and find the detailed figures
Go on WWWombat, just do it. You know you want to
Paul.
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Wait for them to enable vectoring in 2012. This should boost speeds considerably and might take your upload speed back up to the 20Mb mark.
________________________
Connected with O2 Broadband Standard 8.6Mb/1.2Mb
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Go on WWWombat, just do it. You know you want to
Paul.
I do, but SWMBO would go mental if I broke it. I need enough time to unlock it *and* to put it right again if I b***er things up
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your line looks very similar too mine
# xdslcmd info --pbParams
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Max: Upstream rate = 12014 Kbps, Downstream rate = 50444 Kbps
Path: 0, Upstream rate = 10000 Kbps, Downstream rate = 39996 Kbps
Discovery Phase (Initial) Band Plan
US: (0,95) (868,1207) (1972,2783)
DS: (32,859) (1216,1963) (2792,3939)
Medley Phase (Final) Band Plan
US: (0,95) (868,1207) (1972,2783)
DS: (32,859) (1216,1963) (2792,3939)
VDSL Port Details Upstream Downstream
Attainable Net Data Rate: 12014 kbps 50444 kbps
Actual Aggregate Tx Power: 6.6 dBm 11.8 dBm
============================================================================
VDSL Band Status U0 U1 U2 U3 D1 D2 D3
Line Attenuation(dB): 5.6 31.4 45.9 N/A 15.3 38.9 59.7
Signal Attenuation(dB): 7.3 30.6 44.7 N/A 15.3 38.9 59.7
SNR Margin(dB): 7.7 7.7 7.7 N/A 7.0 7.1 7.4
TX Power(dBm): -3.9 -13.3 6.3 N/A 8.1 7.9 4.3
thing is it used to only sync at approx 30000kbps downstream and 8000kbps up
Looks like they don't apply the same band settings to all cabinets as mine looks like this:
# xdslcmd info --pbParams
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Max: Upstream rate = 19805 Kbps, Downstream rate = 67068 Kbps
Path: 0, Upstream rate = 9995 Kbps, Downstream rate = 39998 Kbps
Discovery Phase (Initial) Band Plan
US: (0,95) (880,1195) (1984,2771)
DS: (32,859) (1216,1959) (2792,4083)
Medley Phase (Final) Band Plan
US: (0,95) (880,1195) (1984,2771)
DS: (32,859) (1216,1959) (2792,4083)
VDSL Port Details Upstream Downstream
Attainable Net Data Rate: 19805 kbps 67068 kbps
Actual Aggregate Tx Power: 6.5 dBm 12.8 dBm
============================================================================
VDSL Band Status U0 U1 U2 U3 D1 D2 D3
Line Attenuation(dB): 1.0 24.0 37.0 N/A 12.7 30.3 50.0
Signal Attenuation(dB): 0.9 23.8 36.9 N/A 12.7 30.3 50.0
SNR Margin(dB): 14.3 13.3 12.9 N/A 14.6 14.8 14.6
TX Power(dBm): -4.9 -20.3 6.2 N/A 11.5 7.4 -6.3
Before the update I had a u/s attainable of 15800 and d/s 41800.
The line is approx 600m ti the cab and 6km to the exchange.
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Hi rhino7
Discovery Phase (Initial) Band Plan
US: (0,95) (880,1195) (1984,2771)
DS: (32,859) (1216,1959) (2792,4083)
Medley Phase (Final) Band Plan
US: (0,95) (880,1195) (1984,2771)
DS: (32,859) (1216,1959) (2792,4083)
VDSL Port Details Upstream Downstream
Attainable Net Data Rate: 19805 kbps 67068 kbps
Actual Aggregate Tx Power: 6.5 dBm 12.8 dBm
============================================================================
VDSL Band Status U0 U1 U2 U3 D1 D2 D3
Line Attenuation(dB): 1.0 24.0 37.0 N/A 12.7 30.3 50.0
Signal Attenuation(dB): 0.9 23.8 36.9 N/A 12.7 30.3 50.0
SNR Margin(dB): 14.3 13.3 12.9 N/A 14.6 14.8 14.6
TX Power(dBm): -4.9 -20.3 6.2 N/A 11.5 7.4 -6.3
That's the first one that has been noticed as being a different band plan.
Just to confirm, does it still show as profile 17a?
(xdslcmd info --show)
Paul.
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Those are some very different boundaries to the US and DS plans - particularly the top of the last DS band.
My line is also 600 metres from the cabinet, but our cabinet is only 1.5km from the exchange. My boundaries are the same as MrGrumpy.
There is a factor to the cabinets that is known to change, based on the distance that the cabinet is from the exchange: the transmission power maps.
The maps are meant to ensure that the cabinet's VDSL transmissions do not swamp the exchange's ADSL(2+) transmissions. This means that cabinets closer to an exchange can transmit at slightly higher levels (because the ADSL signals are still high) but must take care over a wider frequency range. The cabinets further away are restricted to lower power levels, but over a smaller range (because the ADSL signals will be lower, but some of the higher frequencies will now be unusable that far out)
I wonder if the changes to these power maps cause the differences to the US/DS boundaries? Channel 868 is around 3.7MHz, so is way above the ADSL frequencies. So maybe not...
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Hi rhino7
Discovery Phase (Initial) Band Plan
US: (0,95) (880,1195) (1984,2771)
DS: (32,859) (1216,1959) (2792,4083)
Medley Phase (Final) Band Plan
US: (0,95) (880,1195) (1984,2771)
DS: (32,859) (1216,1959) (2792,4083)
VDSL Port Details Upstream Downstream
Attainable Net Data Rate: 19805 kbps 67068 kbps
Actual Aggregate Tx Power: 6.5 dBm 12.8 dBm
============================================================================
VDSL Band Status U0 U1 U2 U3 D1 D2 D3
Line Attenuation(dB): 1.0 24.0 37.0 N/A 12.7 30.3 50.0
Signal Attenuation(dB): 0.9 23.8 36.9 N/A 12.7 30.3 50.0
SNR Margin(dB): 14.3 13.3 12.9 N/A 14.6 14.8 14.6
TX Power(dBm): -4.9 -20.3 6.2 N/A 11.5 7.4 -6.3
That's the first one that has been noticed as being a different band plan.
Just to confirm, does it still show as profile 17a?
(xdslcmd info --show)
Paul.
Hi Paul,
The modem definitely shows profile 17a. I checked that via the telnet interface when I noticed the increase in the attainable upload and download speeds in the web interface.
Dave.
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Those are some very different boundaries to the US and DS plans - particularly the top of the last DS band.
My line is also 600 metres from the cabinet, but our cabinet is only 1.5km from the exchange. My boundaries are the same as MrGrumpy.
There is a factor to the cabinets that is known to change, based on the distance that the cabinet is from the exchange: the transmission power maps.
The maps are meant to ensure that the cabinet's VDSL transmissions do not swamp the exchange's ADSL(2+) transmissions. This means that cabinets closer to an exchange can transmit at slightly higher levels (because the ADSL signals are still high) but must take care over a wider frequency range. The cabinets further away are restricted to lower power levels, but over a smaller range (because the ADSL signals will be lower, but some of the higher frequencies will now be unusable that far out)
I wonder if the changes to these power maps cause the differences to the US/DS boundaries? Channel 868 is around 3.7MHz, so is way above the ADSL frequencies. So maybe not...
What are your before and after attainable values? Mine went from 43/15 to 68/20 (or thereabouts). It would be interesting to see your values against mine as your line is a similar length from the cab. It was the fact that it "only" went up to 68 meg that made me look at the band allocation as I'd noticed that other people reported much better improvements in download speed but not always very much improvement in the upload speed (or even a reduction).
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What are your before and after attainable values? Mine went from 43/15 to 68/20 (or thereabouts). It would be interesting to see your values against mine as your line is a similar length from the cab. It was the fact that it "only" went up to 68 meg that made me look at the band allocation as I'd noticed that other people reported much better improvements in download speed but not always very much improvement in the upload speed (or even a reduction).
I don't know the 'before' attainable value, as I didn't unlock the modem until after we went to profile 17a. However, while we synced with a 38717 profile initially, DLM didn't like the error rates on the line, and wiped 4Mbps off us (profile of 34799, download speeds of 33.5Mbps, so i assume a sync of roughly 36Mbps) and turned interleaving on. Upstream was always 10Mbps, so I can't tell the max attainable there. I'll therefore guess that our downstream attainable was the same as actual - around 36 Mbps.
Today, our attainable speeds are 61/17. That is with interleaving turned on - DLM seems to have changed our settings at the weekend. Before the weekend (but still on profile 17a) our attainable speeds were 59/17.
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When I was on 8c my us attainable rate was about 14000 syncing at 10000. When it switched to 17a my us sync dropped to 5000 ds stayed at 40000. My current stats are:-
# /bin/xdslcmd info --pbParams
/bin/xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 2
Max: Upstream rate = 7164 Kbps, Downstream rate = 50208 Kbps
Path: 0, Upstream rate = 6739 Kbps, Downstream rate = 39996 Kbps
Discovery Phase (Initial) Band Plan
US: (0,95) (868,1207) (1972,2783)
DS: (32,859) (1216,1963) (2792,3939)
Medley Phase (Final) Band Plan
US: (0,95) (868,1207)
DS: (32,859) (1216,1963)
VDSL Port Details Upstream Downstream
Attainable Net Data Rate: 7164 kbps 50208 kbps
Actual Aggregate Tx Power: - 4.8 dBm 12.5 dBm
=========================================================
VDSL Band Status U0 U1 U2 U3 D1 D2 D3
Line Attenuation(dB): 6.4 39.8 54.8 N/A 17.7 49.0 69.9
Signal Attenuation(dB): 6.9 38.5 N/A N/A 17.7 49.0 N/A
SNR Margin(dB): 6.7 6.9 N/A N/A 6.9 7.4 N/A
TX Power(dBm): -15.7 -5.2 N/A N/A 10.8 7.9 N/A
My us has gone up a bit after badgering BT. Openreach are not interested. My line length is about 1300m
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Hi Hunter59,
When I was on 8c my us attainable rate was about 14000 syncing at 10000. When it switched to 17a my us sync dropped to 5000 ds stayed at 40000.
If your line length really is 1300m, you don't appear to be doing too badly (in comparison to my 800m to 1000m connection).
You are actually achieving higher speeds, with lower attenuation levels than my connection.
How accurate would you say your estimated 1300m length is?
It appears that all the 17a band plans are being detected at Discovery Phase (Initial) Band Plan for your connection, but they are not all actually being used at Medley Phase (Final) Band Plan
Discovery Phase (Initial) Band Plan
US: (0,95) (868,1207) (1972,2783)
DS: (32,859) (1216,1963) (2792,3939)
Medley Phase (Final) Band Plan
US: (0,95) (868,1207)
DS: (32,859) (1216,1963)
It would appear that your attenuation levels are simply too high to make use of the higher frequencies of the higher Band Plans
VDSL Port Details Upstream Downstream
Attainable Net Data Rate: 7164 kbps 50208 kbps
Actual Aggregate Tx Power: - 4.8 dBm 12.5 dBm
=========================================================
VDSL Band Status U0 U1 U2 U3 D1 D2 D3
Line Attenuation(dB): 6.4 39.8 54.8 N/A 17.7 49.0 69.9
Signal Attenuation(dB): 6.9 38.5 N/A N/A 17.7 49.0 N/A
SNR Margin(dB): 6.7 6.9 N/A N/A 6.9 7.4 N/A
TX Power(dBm): -15.7 -5.2 N/A N/A 10.8 7.9 N/A
These are my current stats:-
| Text | 1
23
45
67
89
1011
1213
1415
1617
1819
2021
22 | # xdslcmd info --pbParams
xdslcmd: ADSL driver and PHY statusStatus: Showtime
Retrain Reason: 1Max: Upstream rate = 6026 Kbps, Downstream rate = 30968 Kbps
Path: 0, Upstream rate = 5840 Kbps, Downstream rate = 23242 Kbps
Discovery Phase (Initial) Band PlanUS: (0,95) (868,1207) (1972,2783)
DS: (32,859) (1216,1963) (2792,3939) Medley Phase (Final) Band Plan
US: (0,95) (868,1207) DS: (32,859) (1216,1963)
VDSL Port Details Upstream DownstreamAttainable Net Data Rate: 6026 kbps 30968 kbps
Actual Aggregate Tx Power: 6.3 dBm 12.1 dBm============================================================================
VDSL Band Status U0 U1 U2 U3 D1 D2 D3 Line Attenuation(dB): 8.6 53.0 63.9 N/A 21.9 63.2 0.1
Signal Attenuation(dB): 14.1 52.0 N/A N/A 21.9 63.2 N/A SNR Margin(dB): 6.5 6.7 N/A N/A 9.4 9.3 N/A
TX Power(dBm): -4.4 5.8 N/A N/A 11.1 5.3 N/A |
My us has gone up a bit after badgering BT. Openreach are not interested. My line length is about 1300m
The slight lowering of US rates appears quite common with the switch from 8c to 17a, usually with a slight increase in DS Rates (currently capped at 40Mb).
Do you recall your DS Attainable rate for 8c, as a comparison with the current Attainable Rate for 17a?
Paul.
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Hello Paul,
The 1300m is measured using the website "where's the path" (http://wtp2.appspot.com). It is actually 1100-1300 depending on cable route.
The most significant thing I think is my US transmit power, it�s pitiful, As yet I have seen nobody else�s stats with a negative aggregate. I think that is cause of the reduced US rate.
My US rate hasn't lowered slightly, it has halved.
I think my original DS attainable rate was about 42000. It�s gone up quite a bit with 17a.
Steve
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Hi Steve,
It might be interesting to see some graphs of your current bit-loading/SNR/QLN levels etc. that may just help to identify the problem area(s).
If you are a Windows user, the tools to generate such graphs can be downloaded via the "Huawei HG612 graphing scripts" link in this TBB post:-
Profile Steps
e.g. these are my recent snapshot graphs:-
Recent snapshot graphs
If you have any previous logs (preferably generated by PuTTy), you could also graph previous stats for comparison purposes.
Getting your ISP/BT to do anything about it would be a whole different ball game though.
Did your US rate deteriorate IMMEDIATELY on being switched from 8c to 17a?
Paul.
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The most significant thing I think is my US transmit power, it�s pitiful, As yet I have seen nobody else�s stats with a negative aggregate. I think that is cause of the reduced US rate.
Did you realise that every cabinet has to employ different power masks to ensure that the VDSL2 signals generated by the cabinet don't swamp the ADSL & ADSL2+ signals generated by the exchange (for people who haven't converted yet?
Cabinets close to the exchange allow for less power-masking (ie allow higher power), but the restriction is held over the whole of the ADSL2+ frequency band.
Cabinets further from the exchange are set to reduce power further, but over smaller frequency bands (under the basis that the higher ADSL2+ frequencies are unusable a certain distance out from the exchange).
I would imagine that upstream power is hit the same way, so I'd predict that your cabinet is quite a long way from your exchange.
My US rate hasn't lowered slightly, it has halved.
I think my original DS attainable rate was about 42000. It�s gone up quite a bit with 17a.
In the old 997 band-plan, the frequencies were split (bar the low U0 part):
D1: 0-3MHz Downstream
U1: 3-5.1MHz Upstream
D2: 5.1-7.05MHz Downstream
You'll have been using virtually all of this spectrum
In the new 998 bandplan, the main change is:
3-3.75MHz is swapped from upstream U1 into downstream D1.
Then, in adding the higher frequencies, the initial change is:
D2: Extended from 7.05MHz to 8.5MHz
As I think BaldEagle pointed out, your modem is not using any frequencies in U2 or D3, so we can forget anything above the 8.5MHz region. If you get the graphs that he describes, we'd find out more accurately, but in essence, it appears that:
a) You have lost 0.75MHz out of a total of 2.1MHz for upstream, or roughly one-third of the spectrum from U1, but gained nothing from U2.
b) You have gained 0.75MHz into D1 and 1.5MHz into D2, out of a previous total of 5MHz - or roughly an extra 50% of the spectrum for downstream. The first 0.75MHz will be capable of carrying more than the second 1.5MHz because of the distance.
So you can see that the scale of the change is actually fairly similar to the kind of scale of the change you have experienced.
I'd agree that your loss of upstream is probably the highest I've seen, but we're not talking about it being a long way outside our expectations. And undoubtedly those power-masks will give everyone different results.
I also agree that you're getting pretty good downstream totals. My old line would only give a max attainable of 60Mbps, at 650 metres, and that included using the U2 and D3 frequencies.
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