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mr_bean
(member) Mon 05-Sep-11 18:35:44

More FTTC line stats

[link to this post]

It seems that asbokid has quietly been beavering away unlocking the Openreach modem firmware enabling the web interface (links on right hand side of page).

Just tried it - flashed my spare modem with no problems and now can see my actual sync speed!

Sorry no cut 'n' paste available but I have:

Sync D/S: 39999 (Kbps)
Sync U/S: 9999 (Kbps)
SNRM D/S: 6.5dB
SNRM U/S: 16.7dB
Attainable D/S: 40800
Attainable U/S 17667
Atten D/S: 0dB <cough>
Atten U/S: 0dB <cough, cough>
D/S transmit power: +10dB

Oh well - not perfect as the attenuation isn't reported - it was 19dB according to the OR engineer at install in April. Interestingly the max attainable hasn't shifted much as it was 41000Kbps then.

Sync/attainable consistent with the line length of approx 650m and graphs published in various places. Not a lot of wriggle room for full downstream sync on the 40/10 product although upstream looks good. It'll be interesting to see what I get if 17a ever comes along. I doubt 'll get 80/20 but I'm sort of hoping for 60/20.

Edited by mr_bean (Mon 05-Sep-11 20:46:12)

MHC
(legend) Mon 05-Sep-11 18:48:34

Re: More FTTC line stats

[re: mr_bean] [link to this post]

In reply to a post by mr_bean:
It seems that asbokid has quietly been beavering away unlocking the Openreach modem firmware enabling the web interface (links on right hand side of page).

Just tried it - flashed my spare modem with no problems and now can see my actual sync speed!

Sorry no cut 'n' paste available but I have:

Sync D/S: 39999 (Kbps)
Sync U/S: 9999 (Kbps)
SNRM D/S: 6.5dB
SNRM D/S: 16.7dB
Attainable D/S: 40800
Attainable U/S 17667
Atten D/S: 0dB <cough>
Atten U/S: 0dB <cough, cough>
D/S transmit power: +10dB

Oh well - not perfect as the attenuation isn't reported - it was 19dB according to the OR engineer at install in April. Interestingly the max attainable hasn't shifted much as it was 41000Kbps then.

Sync/attainable consistent with the line length of approx 650m and graphs published in various places. Not a lot of wriggle room for full downstream sync on the 40/10 product although upstream looks good. It'll be interesting to see what I get if 17a ever comes along. I doubt 'll get 80/20 but I'm sort of hoping for 60/20.

Two minor errors:

2 D/S SNRMs

Transmit power: +10dB is that dBu? dBM?

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

M H C

taurus excreta cerebrum vincit

adebov
(eat-sleep-adslguide) Mon 05-Sep-11 18:55:47

Re: More FTTC line stats

[re: mr_bean] [link to this post]

Hmm.....how long before this particular avenue is closed off wink

Ade

ADSL2+ with BE
DL Sync around 4.8Mbps
UL Sync 1088kbps
DG834GT with DGTeam firmware

deleted
(deleted) Mon 05-Sep-11 20:03:52

Re: More FTTC line stats

[re: MHC] [link to this post]

Hi,

Those zero attenuation figures are obviously wrong.. But it's a firmware bug that's found in other, maybe all Broadcom 63xx VDSL2 modems, and not just the Huawei.

Here at [1] ,for example, are VDSL2 stats from a Pirelli PRGAV4202N modem-router. The Pirelli is connected via a Profile 17a (yum yum!) VDSL2 connection in Germany. It too shows a zero figure in the attenuation columns.

It's a rudimentary firmware error that could easily be corrected. It seems that Broadcom hasn't updated the web interface to show attenuation stats for VDSL2 connections. The device does report credible atten. figures on ADSL2+.

As for the SNR figures, the Openreach/Huawei is correct in reporting two figures.

So far as I know, VDSL2 Annex B Profile 8c as chosen by British Telecom has a frequency band profile that uses two separate downstream frequency bands. [2]

The two separate SNR figures are for those two bands (D1 and D2).

If you get a shell on the HG612 by logging in from LAN-side via telnet or ssh, and issue the command:

# /bin/xdslcmd info --pbParams

You can see more detailed line stats.. The device should report something like this. Hopefully with more impressive figures.. These stats are from a problematic VDSL2 connection...

Text

# /bin/xdslcmd info --pbParams
xdslcmd: ADSL driver and PHY statusStatus: Showtime
Retrain Reason: 0Max:    Upstream rate = 6147 Kbps, Downstream rate = 23312 Kbps
Path:   0, Upstream rate = 1997 Kbps, Downstream rate = 23055 Kbps 
Discovery Phase (Initial) Band PlanUS: (0,95) (696,1183)
DS: (32,687) (1192,1627)Medley Phase (Final) Band Plan
US: (0,95) (696,1183)DS: (32,687) (1192,1627)
       VDSL Port Details       Upstream        DownstreamAttainable Net Data Rate:       6147 kbps         23312 kbps
Actual Aggregate Tx Power:        1.3 dBm           9.5 dBm==============================================================================
  VDSL Band Status        U0      U1      U2      U3      D1      D2      D3  Line Attenuation(dB):  8.5     52.6     N/A     N/A    21.5    65.5     N/A
Signal Attenuation(dB):  9.3     51.2     N/A     N/A    21.5    65.5     N/A        SNR Margin(dB):  14.3    14.1     N/A     N/A    6.2     6.4      N/A
         TX Power(dBm): -9.1     0.8      N/A     N/A    9.2    -1.7      N/A

cheers,
asbokid

[1] http://xdsl.at/viewtopic.php?f=20&t=52581
[2] http://www.itu.int/rec/T-REC-G.993.2-200602-I/en

mr_bean
(member) Mon 05-Sep-11 20:40:02

Re: More FTTC line stats

[re: adebov] [link to this post]

Hmm.....how long before this particular avenue is closed off

Dunno - I'm guessing but I think all asbokid has done for this firmware is tweak the default firewall rules which block HTTP, Telnet and SSH on the LAN interface so that you can get at them. It looks as though over-the-wire firmware updates are possible so the unit might automagically revert to the BT firewall.

mr_bean
(member) Mon 05-Sep-11 20:45:59

Re: More FTTC line stats

[re: MHC] [link to this post]

Two minor errors:

2 D/S SNRMs

Ah, I did say that it wasn't a cut&paste job. 6.5dB downstream, 16.7dB upstream. Have edited the original post.

Transmit power: +10dB is that dBu? dBM?

Says dBmV on the web interface - I guess they mean dBm

MHC
(legend) Mon 05-Sep-11 20:52:36

Re: More FTTC line stats

[re: mr_bean] [link to this post]

dBmV - deciBels relative to 1 millivolt

dBm - deciBels relative to 1 milliwatt

They are not equivalent - you can convert between them but not a straight forward calc.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

M H C

taurus excreta cerebrum vincit

MHC
(legend) Mon 05-Sep-11 21:21:45

Re: More FTTC line stats

[re: deleted] [link to this post]

In reply to a post by asbokid:

Text

# /bin/xdslcmd info --pbParams
xdslcmd: ADSL driver and PHY statusStatus: Showtime
Retrain Reason: 0Max:    Upstream rate = 6147 Kbps, Downstream rate = 23312 Kbps
Path:   0, Upstream rate = 1997 Kbps, Downstream rate = 23055 Kbps 
Discovery Phase (Initial) Band PlanUS: (0,95) (696,1183)
DS: (32,687) (1192,1627)Medley Phase (Final) Band Plan
US: (0,95) (696,1183)DS: (32,687) (1192,1627)
       VDSL Port Details       Upstream        DownstreamAttainable Net Data Rate:       6147 kbps         23312 kbps
Actual Aggregate Tx Power:        1.3 dBm           9.5 dBm==============================================================================
  VDSL Band Status        U0      U1      U2      U3      D1      D2      D3  Line Attenuation(dB):  8.5     52.6     N/A     N/A    21.5    65.5     N/A
Signal Attenuation(dB):  9.3     51.2     N/A     N/A    21.5    65.5     N/A        SNR Margin(dB):  14.3    14.1     N/A     N/A    6.2     6.4      N/A
         TX Power(dBm): -9.1     0.8      N/A     N/A    9.2    -1.7      N/A

There are two UPstream and two DNstream and with an additional two UPstream. and one DNstream which the modem can cope with. Not sure exactly which ones 8C uses but is at least 2 & 2 This is shown in the last 5 lines of your quoted code.

The actual figures:

Text
1 2	US: (0,95) (696,1183) DS: (32,687) (1192,1627)

Show the attenuation figures in both bands - if the router only reports one they I would guess it is only using one band.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

M H C

taurus excreta cerebrum vincit

mr_bean
(member) Mon 05-Sep-11 21:24:10

Re: More FTTC line stats

[re: MHC] [link to this post]

dBmV - deciBels relative to 1 millivolt

dBm - deciBels relative to 1 milliwatt

They are not equivalent - you can convert between them but not a straight forward calc.

I realise that but I thought that xDSL output levels were normally dBm(W), it says dBmV on the web interface but that doesn't really seem appropriate. Oh and +10dBm is a reasonable value for xDSL power output whereas +10dBmV (about -47dBmW*) seems a bit on the low side.

* Based on 600 Ohm**; impedance

** How do I get the symbol in here?

Edited by mr_bean (Mon 05-Sep-11 21:24:39)

MHC
(legend) Mon 05-Sep-11 21:31:17

Re: More FTTC line stats

[re: mr_bean] [link to this post]

I know it must, to some, seem petty but you seem to understand why getting the units exactly correct is important - dBM or dBm or DBm; kb or kB; Mb or MB or mb or mB; dB or dBm; and so on.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

M H C

taurus excreta cerebrum vincit

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