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Standard User rd350ypvs
(regular) Sat 26-Apr-14 10:15:06
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Why are my stats this bad


[link to this post]
 
Hi, had fiber large installed on the 15th April and have just got hold of an unlocked HG612. My original modem is the ECI rev B. Should I be set on interleaved at this depth?

xdslcmd info --pbParams
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Max: Upstream rate = 28094 Kbps, Downstream rate = 96416 Kbps
Path: 0, Upstream rate = 20000 Kbps, Downstream rate = 80000 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: 28094 kbps 96416 kbps
Actual Aggregate Tx Power: 4.5 dBm 13.2 dBm
============================================================================
VDSL Band Status U0 U1 U2 U3 D1 D2 D3
Line Attenuation(dB): 1.2 22.9 34.1 N/A 12.1 28.8 44.9
Signal Attenuation(dB): 1.2 22.8 34.0 N/A 12.1 28.8 44.9
SNR Margin(dB): 10.5 10.0 9.7 N/A 6.6 6.5 6.6
TX Power(dBm): -5.1 -21.3 4.0 N/A 9.6 7.4 7.5
#

Current stats are

xdslcmd info --stats
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Max: Upstream rate = 28091 Kbps, Downstream rate = 96632 Kbps
Path: 0, Upstream rate = 20000 Kbps, Downstream rate = 80000 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): 6.6 9.8
Attn(dB): 0.0 0.0
Pwr(dBm): 13.2 4.5
VDSL2 framing
Path 0
B: 54 236
M: 1 1
T: 64 5
R: 14 16
S: 0.0219 0.3771
L: 25239 5410
D: 1435 1
I: 69 255
N: 69 255
Counters
Path 0
OHF: 129019251 286885
OHFErr: 602 2
RS: 3296679127 3471720
RSCorr: 37382999 43
RSUnCorr: 61068 0

Path 0
HEC: 18404 0
OCD: 236 0
LCD: 236 0
Total Cells: 3738623538 0
Data Cells: 417717097 0
Drop Cells: 0
Bit Errors: 0 0

ES: 122 6
SES: 1 0
UAS: 37 37
AS: 135975

Path 0
INP: 3.00 0.00
PER: 1.04 6.12
delay: 8.00 0.00
OR: 160.02 203.67

Bitswap: 37053 72

Total time = 1 days 12 hours 48 min 58 sec
FEC: 58759766 72
CRC: 753 6
ES: 122 6
SES: 1 0
UAS: 37 37
LOS: 0 0
LOF: 0 0
Latest 15 minutes time = 3 min 58 sec
FEC: 29483 0
CRC: 0 0
ES: 0 0
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
Previous 15 minutes time = 15 min 0 sec
FEC: 106277 0
CRC: 2 0
ES: 1 0
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
Latest 1 day time = 12 hours 48 min 58 sec
FEC: 3141665 11
CRC: 72 0
ES: 13 0
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
Previous 1 day time = 24 hours 0 sec
FEC: 33294561 25
CRC: 523 2
ES: 59 2
SES: 1 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
Since Link time = 1 days 13 hours 46 min 14 sec
FEC: 37382999 43
CRC: 602 2
ES: 73 2
SES: 1 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
#

Stats recorded 26 Apr 2014 10:12:46

DSLAM/MSAN type: IFTN:0xb203 / v0xb203
Modem/router firmware: AnnexA version - A2pv6C035m.d22g
DSL mode: VDSL2
Status: Showtime
Uptime: 1 day 13 hours 46 min 14 sec

Downstream Upstream
Attenuation (dB):
Connection speed (kbps): 80000 20000
SNR margin (dB): 6.6 9.8
Power (dBm): 13.2 4.5
Interleave depth: 1435 1
INP: 3.00 0

RSCorr/RS (%):
RSUnCorr/RS (%): 0.0019 0.0000
ES/hour: 1.14

cheers


Andy
Standard User iand
(fountain of knowledge) Sat 26-Apr-14 15:36:05
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Re: Why are my stats this bad


[re: rd350ypvs] [link to this post]
 
just out of curiosity, why the statement of "why are my line stats this bad"

Your line looks to handle 96M down 28M up
Your link looks to be set to 80M down, 20M up, which I assume is what you are paying for.

What is "bad"?

IanD
Standard User R0NSKI
(fountain of knowledge) Sat 26-Apr-14 16:49:57
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Re: Why are my stats this bad


[re: iand] [link to this post]
 
Because of his interleaving depth, which is:

D: 1435 1

Which is quite a high level, so something must be causing errors on the line or the modems been switched off a few too many times in quick succession.

I'd recommend leaving it alone for a few weeks and see if the DLM relents. It would also be worth harvesting stats to see if any one can spot whats going on.

Use either DLStats or HG612 Modems Stats to collect stats and graph them.


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Standard User rd350ypvs
(regular) Sat 26-Apr-14 17:24:06
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Re: Why are my stats this bad


[re: R0NSKI] [link to this post]
 
Cheers, yes its because of the errors, currently using dslstats and hg612 router stats programs. will post current images here soon



cheers
Standard User jchamier
(eat-sleep-adslguide) Sat 26-Apr-14 18:44:50
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Re: Why are my stats this bad


[re: R0NSKI] [link to this post]
 
In reply to a post by R0NSKI:
Which is quite a high level, so something must be causing errors on the line or the modems been switched off a few too many times in quick succession.

My line is always depth of 1089 and has been like that for the 19 months its been installed. Strangely last week I had 2 days with no interleaving, but it came back. smile

James BT Infinity 2 19/09/2012 - Sold 42/6, Now 52/9, Sync @ 55 / 9.5 Mbps @ 470m approx
15 years broadband (1999 ntl: cablemodem, BT FTTC) - Router: Asus RT-AC68U (merlin) - Modem: HG612 unlocked Typical speedtest
Standard User WWWombat
(fountain of knowledge) Tue 29-Apr-14 12:37:33
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Re: Why are my stats this bad


[re: R0NSKI] [link to this post]
 
In reply to a post by R0NSKI:
Because of his interleaving depth, which is:

D: 1435 1

Which is quite a high level, so something must be causing errors on the line or the modems been switched off a few too many times in quick succession.

Knowing the depth of interleaving alone is insufficient; the interleaving works using a two-dimension array, and the depth only shows one dimension of the array - you need the other dimension to determine the "amount" of interleaving.

In this case it is the value
I 69 255


So interleaving uses an array 1435 x 69.

However, I find that even knowing this isn't particularly useful. By far the best measure of interleaving is to look at the parameters set by DLM directly, and particularly the "delay" parameter:
INP:	 3.00	 0.00
delay:	 8.00	 0.00


OP:

An INP of 3 symbols and a "delay" of 8ms is the standard "first attempt" setting for DLM to choose. That implies that the error stats are bad enough to warrant intervention (or were, at the time DLM intervened), but not so bad that DLM has had to perform any additional intervention.

I do find it useful to look at the parameters for FEC, as these vary quite considerably. In this case, the values are:
R:	 14	 16
N:	 69	 255

This means that the modem is using 14 bytes for FEC protection in every block of 69 bytes downstream; this amounts to 20% overhead. That figure is in line with "standard" overhead for intervention: I've seen values range from 15% to 30%.

Note that the modems have negotiated some upstream FEC overhead (16/255 = 6%), even though DLM has not required it (upstream INP was 0), but interleaving is turned off upstream. This seems to be a regular choice by the modems when there is plenty of spare capacity available upstream.

Back to downstream; when looking at the overall line stats, we see:
Max:	Upstream rate = 28094 Kbps, Downstream rate = 96416 Kbps
Path:	0, Upstream rate = 20000 Kbps, Downstream rate = 80000 Kbps
...
SNR Margin(dB):	10.5	10.0	9.7	N/A	6.6	6.5	6.6

The SNR values (just above 6dB) suggest your modem can only just manage to achieve the 80Mbps sync speed alongside the 20% of overhead for FEC; that would match the 96Mbps of the attainable.

Note: In the past, we have found that the Max attainable speed seen when FEC/interleaving is turned on is too high. If DLM removes intervention, it is likely that the attainable speed will reduce to around 88Mbps.

What distance are you from the cabinet (line distance, rather than as-the-crow-flies distance)?

So, what caused the DLM intervention?

On FTTC, DLM is not very prone to intervening because of modem disconnections; I've seen a figure of 10 disconnections in a day. VDSL2 has a mechanism for the modem to report a loss of power to the DSLAM, so it is always better to power-cycle the modem before disconnecting it from the phone line.

The usual DLM intervention comes from monitoring the error rate - in particular we believe it monitors the value that ES changes over a 24 hour period before intervening, or increasing intervention. It may then monitor the FEC counters to aid its decision on de-intervening; this aspect is less clear.

Right now, your stats show:
OHF:	 129019251	 286885
OHFErr:	 602	 2
RS:	 3296679127	 3471720
RSCorr:	 37382999	 43
RSUnCorr:	61068	 0

and

AS:	 135975

That shows that the FEC process has corrected 37,382,999 errors in 135,975 seconds of uptime. That's 275 errors per second, or 1 million per hour over a 37 hour period.

That sounds like a lot - it means that around 1 in 88 blocks of data needs correcting, so it is no wonder that DLM has intervened - and I think it is likely that the intervention will stay.

However, it also looks to be a successful intervention: The FEC process has only failed to correct 61,068 blocks in that time, which has led to only 602 CRC errors; even better, those errors have occurred over only 122 seconds (the ES value): so less than 100 ES's per day. It is unlikely that DLM will need to add more intervention.

For comparison, my line (with almost identical attenuation) has no DLM intervention. It runs at around 5,000 CRC's per day and 500 ES's per day.
Standard User rd350ypvs
(regular) Tue 29-Apr-14 15:19:07
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Re: Why are my stats this bad


[re: WWWombat] [link to this post]
 
cheers for that wombat, alot of good info for me to digest. Was hoping that the interleaving may be switched off after say leaving the modem on for a bout 2 weeks but if this is going to be permanent then I better get used to it.

The problem I see with FTTC is this

If my original estimate by talktalk was 59mb down 18up then we have 20% loss of throughput in the case of interleaving THEN crosstalk possible problems either now or in the future meaning even less speed, so it then starts to look expensive.

I know that originally my attentuation was 21db line for a 18mb sync before moving to fiber

I am 0.5 miles from the cabinet which is No.6 for LCWAL exchange

On the btspeedtest i NEVER get over 47mb so dont know whats happening there.

anyway, thank you very much all of you for such an informative post.

So it wouldn't really change anything if i powered down the modem and router for at least 30mins every week say???

for simple terms for me to understand lol why is the sync 80/20, my estimate only 59/18 yet throughput is only 47mb when max attainable (think i understand on this) is 96/28 ???

WIsh it would just be like adsl2+ wheres you sync 80/20, you get like 77/18 end of lol

cheers



Andy
Standard User RobertoS
(sensei) Tue 29-Apr-14 15:33:49
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Re: Why are my stats this bad


[re: rd350ypvs] [link to this post]
 
What do you get on the thinkbroadband speed test? Please post the link it provides for the full graphical result.

My broadband basic info/help site - www.robertos.me.uk | Domains,site and mail hosting - Tsohost.
Connection - Plusnet UnLim Fibre (FTTC). Sync ~ 58.7/14.6Mbps @ 600m. - BQM

"Where talent is a dwarf, self-esteem is a giant." - Jean-Antoine Petit-Senn.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Allergy information: This post was manufactured in an environment where nuts are present. It may include traces of understatement, litotes and humour.
Standard User R0NSKI
(fountain of knowledge) Tue 29-Apr-14 15:42:28
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Re: Why are my stats this bad


[re: rd350ypvs] [link to this post]
 
You should be getting speed test results in the seventies. Are you connecting wired or by wireless?

At around 800 meters I'm surprised you getting what you are, I'm 450 meters and get about 45. Perhaps you are closer than you think.

Standard User rd350ypvs
(regular) Tue 29-Apr-14 15:50:03
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Re: Why are my stats this bad


[re: RobertoS] [link to this post]
 
will post the results when home from work.

Yeah I think it is more like 400m from the cabinet,

Connected via 500mbs homeplugs, router is in back bedroom, I am under the stairs in my little hidy hole lol

How do I post hgstats graphs on here? Is it possible, easier to show pictures I guess



Andy

Edited by rd350ypvs (Tue 29-Apr-14 15:51:40)

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