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[dazzlew]

Hi FTTC gurus - can you help me understand what might be the problem here, thanks.

Code: [Select]

xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Max: Upstream rate = 27170 Kbps, Downstream rate = 63772 Kbps
Path: 0, Upstream rate = 20000 Kbps, Downstream rate = 63073 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:      27170 kbps         63772 kbps
Actual Aggregate Tx Power:        5.0 dBm          12.6 dBm
============================================================================
  VDSL Band Status        U0      U1      U2      U3      D1      D2      D3
  Line Attenuation(dB): 1.1 23.4 35.5   N/A 12.6 29.8 47.1
Signal Attenuation(dB): 1.1 23.2 35.3   N/A 12.6 29.8 47.1
        SNR Margin(dB): 9.7 9.8 9.5   N/A 6.1 6.1 6.1
         TX Power(dBm): -5.0 -20.1 4.5   N/A 8.6 7.4 7.3
#

Welcome Visiting Huawei  Home Gateway
Copyright by Huawei Technologies Co., Ltd.
Login:admin
Password:
ATP>sh


BusyBox v1.9.1 (2010-10-15 17:59:06 CST) built-in shell (ash)
Enter 'help' for a list of built-in commands.

# sdslcmd info --pbParams
/bin/sh: sdslcmd: not found
# xdslcmd ifo--pbParams
xdslcmd: invalid command
# xdslcmd info --show
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Max: Upstream rate = 27209 Kbps, Downstream rate = 63772 Kbps
Path: 0, Upstream rate = 20000 Kbps, Downstream rate = 63073 Kbps

Link Power State: L0
Mode: VDSL2 Annex B
VDSL2 Profile: Profile 17a
TPS-TC: PTM Mode
Trellis: U:ON /D:ON
Line Status: No Defect
Training Status: Showtime
Down Up
SNR (dB): 6.1 9.6
Attn(dB): 0.0 0.0
Pwr(dBm): 12.6 5.0
VDSL2 framing
Path 0
B: 239 236
M: 1 1
T: 21 5
R: 0 16
S: 0.1211 0.3771
L: 15855 5410
D: 1 1
I: 240 255
N: 240 255
Counters
Path 0
OHF: 108630 34200
OHFErr: 1 0
RS: 0 2221901
RSCorr: 0 3
RSUnCorr: 0 0

Path 0
HEC: 0 0
OCD: 0 0
LCD: 0 0
Total Cells: 25216502 0
Data Cells: 24386 0
Drop Cells: 0
Bit Errors: 0 0

ES: 1 0
SES: 0 0
UAS: 85 85
AS: 210

Path 0
INP: 0.00 0.00
PER: 1.90 6.12
delay: 0.00 0.00
OR: 100.66 203.67

Bitswap: 39 0

#
ATP>


[waltergmw]

Hi DW & welcome,

You haven't given us too much background to go on.
It might seem you have some line noise which has reduced the Max value but otherwise many would be drooling over those figures !!!

What line estimate does the BT Wholesale checker provide ?

Has your installation been done properly with a new integral filter faceplate and was a JDSU / EXFO Pair Quality Test done ?

Kind regards,
Walter

[dazzlew]

Hello and thanks for the welcome.

I had my Infinity Installed the 8th of Feb - engineer reported full sync 80/20 and Quality Tests done/Faceplated Fitted.
Speedtests backed this up. I was pulling 74 down off Speedtest. Then on the 13th I came home to find my speed had dropped to 64. Coming from a BE broadband background I figured I needed to reboot the modem to sort out a poor sync issue. Now, I'm under the impression that BT's DLM might have kicked in and has dropped my profile.
I've since gone and purchased the HG612 off Ebay to see my sync speeds and I'm concerned that I'm nowhere near the 80 on Day 1. My SNR seems very low - I'm around 400mts from the Cab - newish copper as house is 10 years old and underground.
Checker says upto 53 down and upto 15.

Is the HG612 only pulling the information from the IP Profile? It is currently 61.05 Mbps?

Thanks in advance..

Oh and by the way, is there anyway to run the stats/graphs on a Mac?

[asbokid]

maybe run the command xdslcmd info --pbParams for more detailed stats.  Like these stats below 

Code: [Select]

# xdslcmd info --pbParams
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 2
Max: Upstream rate = 61033 Kbps, Downstream rate = 149908 Kbps
Bearer: 0, Upstream rate = 60015 Kbps, Downstream rate = 100014 Kbps

Discovery Phase (Initial) Band Plan
US: (868,1207) (1972,2783)
DS: (64,859) (1216,1963) (2792,3959)
Medley Phase (Final) Band Plan
US: (868,1207) (1972,2783)
DS: (64,859) (1216,1963) (2792,3959)
       VDSL Port Details       Upstream        Downstream
Attainable Net Data Rate:      61033 kbps        149908 kbps
Actual Aggregate Tx Power:    -   4.2 dBm          14.4 dBm
============================================================================
  VDSL Band Status        U0      U1      U2      U3      D1      D2      D3
  Line Attenuation(dB):   N/A 0.0 0.0   N/A 0.0 0.0 0.0
Signal Attenuation(dB):   N/A 0.0 0.0   N/A 0.0 0.0 0.0
        SNR Margin(dB):   N/A 7.8 8.0   N/A 16.6 19.8 19.4
         TX Power(dBm):   N/A -12.8 -4.9   N/A 12.1 7.9 7.1
#

It may be that the take-up of FTTC from your cabinet is picking up as more punters become aware of FTTC availability.  And what you're witnessing is the effect of crosstalk from all the lines of those new subscribers.

Alternatively, the DSLAM may be imposing an aggressive power cut back on your line to maintain a quality of service for other subscribers, including those who are still receiving broadband via an ADSL DSLAM all the way back in the exchange.

The more detailed the stats you can obtain, e.g. like those plotted by Bald_Eagle's scripts, the more accurate the diagnosis for the sudden reduction in throughput.

As for the Apple Mac,  since it's a flavour of Unix, Burakkucat's scripts should work okay on it.

cheers,  a

[dazzlew]

Hi asbokid.

Food for thought - I was the first FTTC customer and our estate had two options. Slow BB as 2k to the exchange or congested Virgin so it could be down to a rush of new orders.. I'll look into the scripts suggested.

Code: [Select]

Telnet update..
# xdslcmd info --pbParams
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Max: Upstream rate = 27230 Kbps, Downstream rate = 64000 Kbps
Path: 0, Upstream rate = 20000 Kbps, Downstream rate = 63073 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:      27230 kbps         64000 kbps
Actual Aggregate Tx Power:        5.0 dBm          12.6 dBm
============================================================================
  VDSL Band Status        U0      U1      U2      U3      D1      D2      D3
  Line Attenuation(dB): 1.1 23.4 35.5   N/A 12.6 29.8 47.1
Signal Attenuation(dB): 1.1 23.2 35.3   N/A 12.6 29.8 47.1
        SNR Margin(dB): 9.6 9.8 9.6   N/A 6.2 6.2 6.3
         TX Power(dBm): -5.0 -20.1 4.5   N/A 8.6 7.4 7.3
#


[asbokid]

Bald_Eagle is the man for diagnostics, although he will probably want to see the output of his scripts for that 

As for the question of IP profile.. the following line from your xdslcmd output shows us that you're on an 80/20 IP profile.  Your actual upstream capacity is capped at 20Mbps, whereas your attainable downstream rate doesn't achieve 80Mbps, so it doesn't need capping any way.

Code: [Select]

Path:   0, Upstream rate = 20000 Kbps, Downstream rate = 63073 Kbps

Your downstream SNRM of 6dB is very normal.

cheers, a

P.S. The tabulated output from xdslcmd and other tools is a lot easier to read if it is wrapped in [ code ] tags, using the button.

[Bald_Eagle1]

We can see form your Discovery Phase (Initial) Band Plan that you are connected to an ECI DSLAM:-

Discovery Phase (Initial) Band Plan
US: (0,95) (880,1195) (1984,2771)
DS: (32,859) (1216,1959) (2792,4083)

There is a school of thought that the ECI modem syncs at higher speeds than the HG612 when connected to an ECI DSLAM, but logging its stats aren't so easy (or reliable) yet.


Your SNRM looks spot on (the target is 6dB):-
SNR Margin(dB):    9.7    9.8    9.5     N/A    6.1    6.1    6.1   


But DS TX Power does look low(ish) from pbParams data:-
TX Power(dBm):   -5.0   -20.1    4.5     N/A    8.6    7.4    7.3   

It does look O.K. though from --show data:-
Pwr(dBm):   12.6      5.0


As mentioned by asbokid, maybe the DSLAM has cut back the power to avoid swamping nearby ADSL signals that are already quite weak due to having travelled a long way from the exchange.

How far are you from the exchange itself?

There could also be interference 'noise' issues, or even a fault that is affecting the connection at certain frequencies (bridged tap, corroded joint etc.)

However, I have seen lower DS sync speeds than yours on a 400m line, but not with the high US speeds.

If you could capture the output from these commands into a single file, compress it to below 200K & post it as an attachment, I could graph it & post it back here for you:-

xdslcmd info --pbParams
xdslcmd info --Bits
xdslcmd info --linediag
xdslcmd info --show
xdslcmd info --stats       

Separate files could be merged into a single file if necessary.

[dazzlew]

Many thanks for the posts.

I'm happy with the speed, I'm just v curious how come my speed has dropped so much down yet it's still great up.

Yes I'm 2k from the exchange I used to get 13 dwn in BE.
Connection has been very solid at all times before and after Infinity was installed.
I get good pings 12ms to bbc.co.uk.

Bald Eagle I have those stats ill add them tomorrow !

[asbokid]

Here's a ditty little diagram from Huawei.  It shows DPBO - downstream power back-off - and an explanation for why it is needed.



It's taken from this document:  http://pdfcast.org/pdf/vdsl2-parameter-descriptions

cheers, a

[dazzlew]

Thanks AsboKid.
Ill need to kick off a campaign to fill up the cab so everyone moves off Adsl..

[Bald_Eagle1]

I'm just v curious how come my speed has dropped so much down yet it's still great up.

Me too.

Yes I'm 2k from the exchange I used to get 13 dwn in BE.
Connection has been very solid at all times before and after Infinity was installed.
I get good pings 12ms to bbc.co.uk.

Possibly NOT DPBO then.
I'm around 5.3km from my exchange & used to only achieve 1Mbps on my ADSL connection.

Being around 1000m from the cabinet, I don't get great speeds due to high attenuation, but DS TX Power doesn't seem to be backed off too much in the D1 band (which includes the same frequencies as ADSL connections):-

Code: [Select]

xdslcmd info --pbParams
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 2
Max: Upstream rate = 5646 Kbps, Downstream rate = 30148 Kbps
Path: 0, Upstream rate = 5734 Kbps, Downstream rate = 25495 Kbps

Discovery Phase (Initial) Band Plan
US: (0,95) (868,1207) (1972,2783)
DS: (32,859) (1216,1963) (2792,3959)
Medley Phase (Final) Band Plan
US: (0,95) (868,1207)
DS: (32,859) (1216,1963)
       VDSL Port Details       Upstream        Downstream
Attainable Net Data Rate:       5646 kbps         30148 kbps
Actual Aggregate Tx Power:        6.3 dBm          12.6 dBm
============================================================================
  VDSL Band Status        U0      U1      U2      U3      D1      D2      D3
  Line Attenuation(dB): 8.2 52.4   N/A   N/A 21.5 62.6 0.1
Signal Attenuation(dB): 8.2 51.7   N/A   N/A 21.5 62.6   N/A
        SNR Margin(dB): 6.0 5.9   N/A   N/A 6.3 6.4   N/A
         TX Power(dBm): -4.1 5.8   N/A   N/A 11.4 6.2   N/A




Bald Eagle I have those stats ill add them tomorrow !

Good. They MAY just tell us something.

It's a shame you don't have any stats right from installation though that could be used for comparison.

[Finguz]

There is a school of thought that the ECI modem syncs at higher speeds than the HG612 when connected to an ECI DSLAM..

Is there any evidence of this yet?

[Bald_Eagle1]

Some users have claimed that is the case. However, we don't yet have like for like stats from the different modems for comparison purposes.

[dazzlew]

Stats today - Sync is > Attainable..

[Bald_Eagle1]

Stats today - Sync is > Attainable..

The graphs montage from your log is attached.

It does look like you have a rather 'noisy' connection.

This is seen in the SNR graph & the QLN graph.
The thicknes of the red lines is actually fluctuation between tones.

Ideally, a thin & smooth red line, as close to horizontal as possible is what would constitute a quiet connection.

Looking at the sync speed being higher than attainable rate, it would appear that the connection must have synced at a quieter time than when you grabbed these stats.

As Retrain Reason is 0, that usually signifies either a user initiated resync or a problem.
Did you initiate the latest resync yourself?


QLN isn't fantatsic either.
Ideally values would be around -140dB across the tones, which is quieter than the -120dB or so shown for the D2 band.

Unless the connection has recently been affected by increased crosstalk, I really have no suggestion as to why you initially achieved higher sync speeds.
Interleaving is still OFF & Impulse Noise protection (INP - not shown in the graphs, but recorded in the log) are both zero, so DLM hasn't taken agressive action yet.

Apart from quite a high number of errored seconds, everything else looks reasonable, so I suspect that DLM may well have settled down the connection at a lower sync speed to maintain stability, without the need to apply interleaving & so on (yet).

Total time = 1 days 1 hours 47 min 3 sec
FEC:      0      0
CRC:      8675      0
ES:      1174      3
SES:      10      0
UAS:      22      22
LOS:      0      0
LOF:      0      0