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Standard User johnhodg
(newbie) Mon 26-May-14 16:14:19
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Could someone take a look at my line stats


[link to this post]
 
Hi could someone please take a look at my line stats from a HG612 I have had connected for 3 days, I have very limited knowledge of BT FTTC VDSL2 I am on infinity 2 option and live about 250 Mts from the cabinet. BT line checker says I should get (80 to 66.8 Down) (20 Ė 19.9 Up) Clean line and (79.5 Ė 52.1 Down) (20 - 17.7 Up) Impacted line. As I am at the bottom of the impacted line and only approx. 250 mts from cabinet could this low download speed be due to a Line fault, the SNR does not fluctuate very much. Or possibly poor quality cables from cabinet. Any suggestions welcome.

PS, I have previously been connected for over 3 weeks without disconnections

Thanks John

xdslcmd info --pbParams
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Max: Upstream rate = 24100 Kbps, Downstream rate = 53832 Kbps
Path: 0, Upstream rate = 20000 Kbps, Downstream rate = 54291 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: 24100 kbps 53832 kbps
Actual Aggregate Tx Power: 4.4 dBm 13.7 dBm
============================================================================
VDSL Band Status U0 U1 U2 U3 D1 D2 D3
Line Attenuation(dB): 0.1 16.2 24.0 N/A 9.3 21.1 33.7
Signal Attenuation(dB): 0.1 16.0 24.0 N/A 9.3 21.1 33.7
SNR Margin(dB): 7.3 7.5 7.0 N/A 5.7 5.9 5.9
TX Power(dBm): -5.2 -128.0 3.8 N/A 10.8 7.4 7.3
#
============================================================================

xdslcmd info --stats
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Max: Upstream rate = 24297 Kbps, Downstream rate = 53376 Kbps
Path: 0, Upstream rate = 20000 Kbps, Downstream rate = 54291 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): 5.8 7.3
Attn(dB): 0.0 0.0
Pwr(dBm): 13.4 4.4
VDSL2 framing
Path 0
B: 239 236
M: 1 1
T: 64 5
R: 0 16
S: 0.1407 0.3771
L: 13648 5410
D: 1 1
I: 240 255
N: 240 255
Counters
Path 0
OHF: 112890732 561771
OHFErr: 1086 119
RS: 0 6651
RSCorr: 0 1121
RSUnCorr: 0 0

Path 0
HEC: 1108 0
OCD: 0 0
LCD: 0 0
Total Cells: 809971435 0
Data Cells: 320195496 0
Drop Cells: 0
Bit Errors: 0 0

ES: 576 111
SES: 0 0
UAS: 79 79
AS: 255100

Path 0
INP: 0.00 0.00
PER: 2.25 6.12
delay: 0.00 0.00
OR: 88.85 203.67

Bitswap: 41066 395

Total time = 1 days 23 hours 43 min 54 sec
FEC: 0 0
CRC: 1091 0
ES: 576 111
SES: 0 0
UAS: 79 79
LOS: 0 0
LOF: 0 0
Latest 15 minutes time = 13 min 54 sec
FEC: 0 0
CRC: 40 0
ES: 7 0
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
Previous 15 minutes time = 15 min 0 sec
FEC: 0 0
CRC: 2 0
ES: 2 0
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
Latest 1 day time = 23 hours 43 min 54 sec
FEC: 0 0
CRC: 273 0
ES: 180 27
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
Previous 1 day time = 24 hours 0 sec
FEC: 0 0
CRC: 245 0
ES: 169 51
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
Since Link time = 2 days 22 hours 51 min 39 sec
FEC: 0 1121
CRC: 1086 119
ES: 572 110
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
Standard User Seansmit17
(eat-sleep-adslguide) Mon 26-May-14 17:39:13
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Re: Could someone take a look at my line stats


[re: johnhodg] [link to this post]
 
I could be wrong and im sure someone will correct me if I am,

But your attenuation and SNR dont seem to match up. Your SNR looks rather low and thus causing the low download sync speed.

How is your modem connected in the house? Is it on an extension or connected to the master socket? How is the condition of the wiring? Is there any noise on the phone line?

TalkTalk 80Mb
Current Line Status (Est)

Connection Speed 79999 Kbps 19999 Kbps
Standard User johnhodg
(newbie) Mon 26-May-14 18:06:48
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Re: Could someone take a look at my line stats


[re: Seansmit17] [link to this post]
 
Thanks for the fast reply, I have wall mounted the modem next to the master socket with approx 12" Inches of cable Cat5 with rj11 on both ends the modem is connected to the R7000 router with 10 mts Cat 6 sheilded cable, I have done all this to avoid/reduce EMI.
Infinity was installed in April this year constant disconnections with HH5, Bt repaired line faults fitted new line from pole to house and filter on master socket but did not reset DLM. phone line has no noise every time I've checked.


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Standard User jchamier
(eat-sleep-adslguide) Mon 26-May-14 18:36:23
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Re: Could someone take a look at my line stats


[re: johnhodg] [link to this post]
 
In reply to a post by johnhodg:
Any suggestions welcome
Try using one of the tools (DSLstats or HG612 modem stats) to get some graphs and track changes over time.

HG612 modem stats:
http://forum.kitz.co.uk/index.php/topic,12284.0.html
http://www.freewarefiles.com/HG612-Modem-Stats_progr...

DSLstats
http://www.s446074245.websitehome.co.uk/

James BT Infinity 2 19/09/2012 - Sold 42/6, Now 52/9, Sync @ 55 / 9.5 Mbps @ 470m approx
19/5/2014 - just ordered PlusNet Unlimited Fibre - awaiting activation date
15 years broadband (1999 ntl:cablemodem trialist) - Router: Asus RT-AC68U (merlin) - Modem: HG612 unlocked Typical BT speedtest
Standard User johnhodg
(newbie) Mon 26-May-14 19:33:35
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Re: Could someone take a look at my line stats


[re: jchamier] [link to this post]
 
I have been using DSLstats but I donít really understand I have tried to put some on Photo bucket donít know if they show any problems.

http://s55.photobucket.com/user/johnhodg/slideshow/
Standard User Chrysalis
(legend) Mon 26-May-14 20:08:57
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Re: Could someone take a look at my line stats


[re: johnhodg] [link to this post]
 
that looks quite bad. The stand out sign is you achieving 20000 but downstream is nowhere near 80000 (similiar issue I been having).

Its much more common for people e.g. to have mid to high 60s sync and not manage 20000, so it shows how underperforming your downstream is. Also your upstream is lower than what it should be based on your attenuation.

Either you have very bad crosstalk, or is a fault.

My advice be useless tho, as my experience is openreach engineers tend to brush off BTw estimates and just say line is within spec.

After quick glance at your graphs, also like me your lower DS tones cannot even max out the bitloading. Which is bizzarre, I have same issue in that regard.

Even on a 4km adsl line my lower tones could max out bitloading, so this seen on much shorter vdsl lines is odd.

Edited by Chrysalis (Mon 26-May-14 20:17:22)

Standard User WWWombat
(fountain of knowledge) Wed 28-May-14 18:01:09
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Re: Could someone take a look at my line stats


[re: johnhodg] [link to this post]
 
Summary:
Downstream, your SNR values look depressed across almost the full frequency range, leading to low bit-loading values. However, attenuation looks fine for the 250m distance, and you are suffering from little interference or errors. DLM has not intervened.

Something seems to be wrong with the line, but others with more experience of copper fault-finding will have to suggest an actual cause.

Extra graphs from the other stats software might help.

Details:
Looking at the text stats, I can see the following:

- Your line attenuation looks right for your distance. Your 3 values (9.3dB, 21dB and 33dB) are about 20-25% less than mine (11.6, 28 and 43dB) for a distance of approx 350 metres.

- Your upstream speed matches mine, in both actual and attainable. With the distance, you'd perhaps expect your attainable speed to be slightly higher than that. However, you appear to be transmitting at a lower power than mine; I suspect your modem has gone through an "upstream power backoff" process to ensure that your line is not causing too much interference to other lines. This process is deliberate, to stop close lines from swamping distant lines.

Your power values are -5.2, -128, 3.8dBm for an aggregate of 4.4dBm, while mine has values of -1.7, -20.8 and 6.5dBm for an aggregate of 7.7dBm.

The net result is that your line is left with an upstream SNRM of 7dB, while mine has an SNRM of 15dB. However, I don't think this indicates a fault.

- Upstream, DLM has not ordered either FEC or interleaving. There is spare capacity in this direction, so the modems have chosen to use FEC without interleaving. This offers a little protection from errors, without any particular downsides.

- Downstream, things are the opposite way around. The speed is markedly low for the distance (and for the attenuation), but is not explained by the bandwidth being stolen for FEC/interleaving: DLM has not intervened, and your error rate is fairly low.

The modems on your line seem to spot this deficiency, and have negotiated a higher power to attempt to compensate. Your power values are 10.8, 7.4 and 7.3dBm for an aggregate of 13.7dBm. My equivalent figures are 9.7, 7.9 and 6.9dBm for an aggregate of 13.1dBm.

- Again, DLM has not intervened in the downstream direction; you have no FEC or interleaving on the line.

You are running an error rate of around 250 CRC's per day, resulting in around 170 ES's per day. This latter figure is probably low enough that DLM would reduce intervention if any were in place; for comparison, I get around 5,000 CRC's per day resulting in 500 ES's per day, and don't get DLM intervention.

- The text stats tell us little else about what might be going on.

Of the graphs, there are a couple of useful ones:
- Graph 11 shows us that the downstream SNRM stays pretty constant over time. This backs up the error figures - you aren't getting periods of noise coming along and interfering.

- Graph 5 shows the SNR per tone (frequency) for both upstream and downstream, and the consequent bit loading value.

For upstream, this shows that you get very good performance in the U2 band (better than mine), and not such good performance in the U1 band.

For downstream, the picture is much worse, across all the frequency bands:
- D3's SNR values seem to start out 10dB depressed compared to mine; though yours flatlines where mine drops with distance (as you'd expect), so the difference gradually reduces. The net result, in bitloading, is that you seem to be losing around 2 bits from every tone.
- D2's SNR value is around 12dB lower than mine, and stays that way throughout. You are losing about 3 bits from every tone here.
- D1 is more complicated.

The shape of D1 gets a little confused by a technique that the FTTC cab uses to prevent interference with local ADSL lines. This "power mask" technique reduces power where it expects ADSL signals to exist, and the amount of power reduction depends on how strong those ADSL signals are expected to be. This means the size & shape of the power-reduction depends on the distance between exchange and cabinet.

The shape of D1 for you, with a small dip at tone 450 or so, suggests your cabinet is pretty close to the exchange - probably below 1km. My line has a much more pronounced dip at tone 300, as the cabinet is a middling distance from the exchange.

Having said that, your SNR shape in the tones up to 450 isn't too bad (I think); your SNR values drop from 48dB to 33dB over that frequency range, where mine drops from 48dB to 20dB over my masked range. I reckon you will have lost a few dB over that portion, but nowhere near as bad as the drop in D2 or D3.

However, the portion of D1 from tone 450 upwards doesn't look good. The SNR increases again, but only up to 36dB, and it only increases gradually - whereas my line increases dramatically from 20dB back up to 52dB before beginning a gradual decline.

You look to have lost at least 12dB in the higher portion of D1, amounting to 4 bits per tone.

Overall, it looks like you've lost a lot of downstream capability over the frequency range from tone 450 upwards. But I couldn't say why - perhaps there is a faulty; perhaps there is a large amount of noise and/or crosstalk in your line.

Some more clues might be gained by looking at two additional graphs, which come from the other sets of stats software: the HLog graph (which gives an idea of the basic capability of the copper line) and the QLN graph (quiet line noise, which gives you an idea of how much noise is present in your environment just before your modem synchronises). These graphs might help others determine whether something is wrong with your copper line.

I'll post my stats and graphs for you to compare...
Standard User WWWombat
(fountain of knowledge) Wed 28-May-14 18:03:57
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Re: Could someone take a look at my line stats


[re: johnhodg] [link to this post]
 
My stats:

xdslcmd info --stats
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason:	0
Last initialization procedure status:	0
Max:	Upstream rate = 23944 Kbps, Downstream rate = 81772 Kbps
Bearer:	0, Upstream rate = 19999 Kbps, Downstream rate = 79987 Kbps

Link Power State:	L0
Mode:			VDSL2 Annex B
VDSL2 Profile:		Profile 17a
TPS-TC:			PTM Mode(0x0)
Trellis:		U:ON /D:ON
Line Status:		No Defect
Training Status:	Showtime
		Down		Up
SNR (dB):	 6.7		 15.2
Attn(dB):	 16.7		 0.0
Pwr(dBm):	 13.1		 7.1
			VDSL2 framing
			Bearer 0
MSGc:		18		26
B:		239		237
M:		1		1
T:		23		42
R:		0		16
S:		0.0955		0.3781
L:		20104		5374
D:		1		1
I:		240		127
N:		240		254
			Counters
			Bearer 0
OHF:		326706117		872881
OHFErr:		67341		926
RS:		0		3358818
RSCorr:		0		9306
RSUnCorr:	0		0

			Bearer 0
HEC:		29346		0
OCD:		784		0
LCD:		784		0
Total Cells:	1472136768		0
Data Cells:	749724345		0
Drop Cells:	0
Bit Errors:	0		0

ES:		4655		555
SES:		90		0
UAS:		35		35
AS:		540337

			Bearer 0
INP:		0.00		0.00
INPRein:	0.00		0.00
delay:		0		0
PER:		1.65		3.98
OR:		116.09		64.22
AgR:		80103.09	20063.54

Bitswap:	378547/378547		7500/7523

Total time = 1 days 6 hours 6 min 12 sec
FEC:		0		9306
CRC:		67341		926
ES:		4655		555
SES:		90		0
UAS:		35		35
LOS:		0		0
LOF:		0		0
LOM:		0		0
Latest 15 minutes time = 6 min 12 sec
FEC:		0		4
CRC:		1		1
ES:		1		1
SES:		0		0
UAS:		0		0
LOS:		0		0
LOF:		0		0
LOM:		0		0
Previous 15 minutes time = 15 min 0 sec
FEC:		0		14
CRC:		8		2
ES:		5		2
SES:		0		0
UAS:		0		0
LOS:		0		0
LOF:		0		0
LOM:		0		0
Latest 1 day time = 6 hours 6 min 12 sec
FEC:		0		89
CRC:		168		21
ES:		91		20
SES:		0		0
UAS:		0		0
LOS:		0		0
LOF:		0		0
LOM:		0		0
Previous 1 day time = 24 hours 0 sec
FEC:		0		1224
CRC:		2546		133
ES:		538		85
SES:		0		0
UAS:		0		0
LOS:		0		0
LOF:		0		0
LOM:		0		0
Since Link time = 6 days 6 hours 5 min 35 sec
FEC:		0		9306
CRC:		67341		926
ES:		4655		555
SES:		90		0
UAS:		0		0
LOS:		0		0
LOF:		0		0
LOM:		0		0


and
xdslcmd info --pbParams
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason:	0
Last initialization procedure status:	0
Max:	Upstream rate = 23944 Kbps, Downstream rate = 81772 Kbps
Bearer:	0, Upstream rate = 19999 Kbps, Downstream rate = 79987 Kbps

Discovery Phase (Initial) Band Plan
US: (7,32) (871,1205) (1972,2782) 
DS: (33,859) (1216,1961) (2793,3970) 
Medley Phase (Final) Band Plan
US: (7,32) (871,1205) (1972,2782) 
DS: (33,859) (1216,1961) (2793,3970) 
	  VDSL Port Details		  Upstream		  Downstream
Attainable Net Data Rate:	    23944 kbps		    81772 kbps
Actual Aggregate Tx Power:	       7.1 dBm		     13.1 dBm
====================================================================================
  VDSL Band Status	 U0	 U1	 U2	 U3	 U4	 D1	 D2	 D3
  Line Attenuation(dB):	 4.4	 22.3	 33.7	  N/A	  N/A	 11.6	 28.2	 43.0	
Signal Attenuation(dB):	 4.4	 21.1	 32.7	  N/A	  N/A	 16.3	 27.9	 43.0	
	SNR Margin(dB):	 16.9	 15.1	 15.2	  N/A	  N/A	 6.7	 6.7	 6.7	
	 TX Power(dBm):	-1.7	-20.8	 6.5	  N/A	  N/A	 9.7	 7.9	 6.9
Standard User WWWombat
(fountain of knowledge) Wed 28-May-14 18:09:38
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Re: Could someone take a look at my line stats


[re: johnhodg] [link to this post]
 
For comparison, a few of my graphs...

The SNR graph:
http://postimg.org/image/eepate4wt/

The bit-loading graph:
http://postimg.org/image/qevl2uln3/

The Hlog graph:
http://postimg.org/image/43c0xzuqx/

The QLN graph:
http://postimg.org/image/larwvgswt/
Standard User johnhodg
(newbie) Wed 28-May-14 21:13:08
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Re: Could someone take a look at my line stats


[re: WWWombat] [link to this post]
 
Wow thanks for that, going into the the data in such detail I have read it a number of times and slowly beginning to understand your findings, not being very technically minded and in my late 60's I'm always willing to learn, also having your data to compare helps me. I will start to monitor what you suggested, at the end of the day if it is a line or cabinet problem how do I get Open reach to repair when all BT India say the Line is OK and your within profile even though it's the lower end of there impacted line estimate. Thanks again
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