Kitz Forum
Broadband Related => FTTC and FTTP Issues => Topic started by: bobmoss on August 20, 2018, 10:56:23 AM
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Hi, I've just had FTTC installed last week and today have installed DSLStats to look at my stats.
Looking at the SNR Margin graph, my Upstream is a steady flat line at 6.1db, however the downstream is all over the place. It has highs of 8.5 and lows of 4.8, it seems to be varying minute by minute.
I've attached a screenshot to show what I mean.
Is this normal? or does it indicate an issue?
I've got no phone extensions and if I unplug the phone it makes no difference at all. I've got a Mk4 VDSL faceplate installed.
Thanks.
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Is there background noise on the phone line when you use the quiet line test (dial 17070 option 2).
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Thanks for the reply. I've just plugged in a corded phone and tried that, no noise, clicks are anything.
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Can you post your Hlog and QLN from DslStats.
The varying SNRM certainly isn't the norm but I've seen it on a number of lines.
It could be something simple like a neighbouring line with a faulty modem reconnecting to some other intermittent noise coming from who knows where what.
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Attached are my QLog and Hlog graphs. Thanks.
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I've had a look at the overnight graphs and the SNR margin goes all over the place overnight too, doesn't seem to be any difference depending on the time of day.
Thanks.
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The swing is more than 3dB so not normal. :(
Upstream is rock steady. If there was an impending fault such as a high open or bad wiring at the socket, then I'd expect to see something on the upstream too.
QLN shows some 'nice' regular bumps at 3150+ which usually indicates crosstalk, but I also note each curve starts with a spike.
Cant particularly spot anything obvious in hlog... its an even curve drop. Bit of spikyness at tail end, but thats not unusual at the higher frequencies.
From the provided graphs I'm not sure what it could be other than some sort of REIN type noise.
I'm presuming from the lack of comments from the other guys that they can't spot anything telling either :/
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I'm presuming from the lack of comments from the other guys that they can't spot anything telling either :/
I confess to scratching my head . . . and not coming up with any sensible conclusion. :(
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Hi
It’s just a thought, sorry if I am wrong but does the line bypass any tress or overhanging branches
If it does, it could be rubbing
Many thanks
John
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Hmm . . . Then we would need to have a category of frequency division duplex (FDD) tree branches which only affect the DS and not the US. :-\
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Good thought, but it is a bit odd that upstream is so steady.
You could perhaps look at the bitload graphs to see if any tones may be struggling. Also bitswaps per tone to see if there is a lot of bit swap at a particular frequency (both of these are under the 'Bits' tab). Having looked at the QLN though unless it is intermittent noise bursts I suspect that may not tell us a lot either.
Its perhaps also worth looking at the SNRM per Band for the downstream to see if there is any of the subtone bands more affected than the others.
Without any further clues to go on, I would suspect that its most likely noise being injected into the line, but it is extremely difficult to say based on what graphs Ive seen so far.
Could I suppose be a line card flapping, but Openreach tend to pick these types of faults up themselves these days, as it will usually affect a batch of users on the same DSLAM.
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Hi
Many thanks and sorry, I did say I could be wrong sorry
A couple of thoughts, which maybe dismissed as I’m sure they will be
Does the line run parallel to any mains cable
Is it possible to double filter the connection and then see the result
Many thanks
John
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Thanks evereyone for helping me out with this - it's much appreciated!
To answer a few questions and give a bit of an overview, I live in a small township on the Isle Of Skye and Fibre has only been available here for about a month. There are about 30 houses here and I am roughly 400 - 500m from the cabinet (my guess of line length). My phone cable runs underground all the way to the cabinet but some other properties have overhead cables.
When I first had Fibre installed last week I was using a Draytek 130 modem and didn't notice the SNR going up and down (does it report actual SNR?) but wasn't really looking for it. I installed a Zyxel VMG1312-B10D so that I could run DSLStats as my speed is around 40Mbs and the (low) estimate from my ISP was 60Mbs. Could it be a faulty modem?
I my house, the cable doesn't run parallel to any mains cables, but it could elsewhere.
I've included a few more graphs as requested from DSLStats.
Thanks.
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Draytek 130 modem and didn't notice the SNR going up and down
Without logging facilities it would be hard to spot.
my speed is around 40Mbs and the (low) estimate from my ISP was 60Mbs
So the line is actually syncing lower than the estimates? It's possible that DLM has spotted the SNRM spiking which may have been causing errors... and thus taken action which would lower your sync speed.
If you can provide full stats, then we should be able to see if DLM has taken any action on your line.
This info can be obtained via the telnet command: adsl info --stats or alternatively C&P everything under the 'Connection Stats' tab in DSL stats - Telnet Data.
If your actual sync speed is much lower than estimates then you should be able to get your ISP involved to ask for an engineers visit. I notice that you are with one of the 'better' ISPs when it comes to fault reporting.
What does BTw estimate your line capable of? https://www.dslchecker.bt.com/
I live in a small township on the Isle Of Skye
One of our other regs lives on Skye, but not fortunate enough to have access to FTTC yet.
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I had some basic logging on the Draytek but it was only once every 10 minutes.
Attached is my dslchecker stats - To be honest I'm not sure they are correct, they are higher than I thought possible with my distance from the cab.
I think my next step will be to get Zen involved, but I wanted to rule out as many possibilities here as possible before contacting them.
One of our other regs lives on Skye, but not fortunate enough to have access to FTTC yet.
It's a bit of a lottery on Skye at the moment as to who gets it. We are lucky here as they laid fibre to a big mast to get highspeed internet to one of the islands and so put in a cabinet for us as part of that. People in the next township can't get it but they are pencilled in for FTTP!
Here are my C&P'd full stats:
xdslctl info --stats
xdslctl: ADSL driver and PHY status
Status: Showtime
Last Retrain Reason: 1
Last initialization procedure status: 0
Max: Upstream rate = 9708 Kbps, Downstream rate = 47684 Kbps
Bearer: 0, Upstream rate = 9682 Kbps, Downstream rate = 45932 Kbps
Bearer: 1, Upstream rate = 0 Kbps, Downstream rate = 0 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): 4.6 6.5
Attn(dB): 22.3 0.0
Pwr(dBm): 13.0 5.2
VDSL2 framing
Bearer 0
MSGc: -6 26
B: 227 237
M: 1 1
T: 0 46
R: 10 16
S: 0.1579 0.7812
L: 12060 2601
D: 4 1
I: 238 127
N: 238 254
Q: 4 0
V: 0 0
RxQueue: 112 0
TxQueue: 28 0
G.INP Framing: 18 0
G.INP lookback: 28 0
RRC bits: 0 24
Bearer 1
MSGc: 90 -6
B: 0 0
M: 2 0
T: 2 0
R: 16 0
S: 10.6667 0.0000
L: 24 0
D: 1 0
I: 32 0
N: 32 0
Q: 0 0
V: 0 0
RxQueue: 0 0
TxQueue: 0 0
G.INP Framing: 0 0
G.INP lookback: 0 0
RRC bits: 0 0
Counters
Bearer 0
OHF: 0 471579
OHFErr: 44444 1
RS: 106855784 21683215
RSCorr: 3103460 4
RSUnCorr: 0 0
Bearer 1
OHF: 263657 0
OHFErr: 1234 0
RS: 1581572 0
RSCorr: 263634 0
RSUnCorr: 1216 0
Retransmit Counters
rtx_tx: 4694416 0
rtx_c: 1945820 0
rtx_uc: 3218062 0
G.INP Counters
LEFTRS: 4228 0
minEFTR: 43189 0
errFreeBits: 23348514 0
Bearer 0
HEC: 0 0
OCD: 0 0
LCD: 0 0
Total Cells: 274815489 0
Data Cells: 3540979 0
Drop Cells: 0
Bit Errors: 0 0
Bearer 1
HEC: 0 0
OCD: 0 0
LCD: 0 0
Total Cells: 0 0
Data Cells: 0 0
Drop Cells: 0
Bit Errors: 0 0
ES: 23034 3
SES: 8962 0
UAS: 100 89
AS: 4236
Bearer 0
INP: 52.00 0.00
INPRein: 1.00 0.00
delay: 0 0
PER: 0.00 9.01
OR: 0.01 28.38
AgR: 46033.29 9710.69
Bearer 1
INP: 2.50 0.00
INPRein: 2.50 0.00
delay: 0 0
PER: 16.06 0.01
OR: 47.81 0.01
AgR: 47.81 0.01
Bitswap: 3000/3025 13/13
Total time = 12 hours 57 sec
FEC: 79253419 11
CRC: 398463 3
ES: 23034 3
SES: 8962 0
UAS: 100 89
LOS: 1 0
LOF: 6 0
LOM: 580 0
Retr: 1
HostInitRetr: 0
FailedRetr: 0
Latest 15 minutes time = 57 sec
FEC: 35007 0
CRC: 506 0
ES: 28 0
SES: 11 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
LOM: 3 0
Retr: 0
HostInitRetr: 0
FailedRetr: 0
Previous 15 minutes time = 15 min 0 sec
FEC: 605760 3
CRC: 9408 0
ES: 484 0
SES: 183 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
LOM: 77 0
Retr: N/A
HostInitRetr: N/A
FailedRetr: N/A
Latest 1 day time = 12 hours 57 sec
FEC: 79253419 11
CRC: 398463 3
ES: 23034 3
SES: 8962 0
UAS: 100 89
LOS: 1 0
LOF: 6 0
LOM: 580 0
Retr: 1
HostInitRetr: 0
FailedRetr: 0
Previous 1 day time = 0 sec
FEC: 0 0
CRC: 0 0
ES: 0 0
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
LOM: 0 0
Retr: 0
HostInitRetr: 0
FailedRetr: 0
Since Link time = 1 hours 10 min 35 sec
FEC: 3103460 4
CRC: 44444 1
ES: 2493 1
SES: 952 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
LOM: 304 0
Retr: 0
HostInitRetr: 0
FailedRetr: 0
NTR: mipsCntAtNtr=0 ncoCntAtNtr=0
$
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I am roughly 400 - 500m from the cabinet
You may be correct that it is ambitious... but if that is a brand new cab and not many on it yet, then at a stretch its possible until crosstalk gets a hold. To give an indication when I first went live my max attain was ~40 Mbps more than it is now.
Previous 15 minutes time = 15 min 0 sec
FEC: 605760 3
CRC: 9408 0
ES: 484 0
SES: 183 0
Latest 1 day time = 12 hours 57 sec
FEC: 79253419 11
CRC: 398463 3
ES: 23034 3
SES: 8962 0
I'm afraid that is not good at all :'(
You are getting a heck of a lot of Errored Seconds (ES). DLM allows ~2880 per day before it will take action.
Combination of the SNRM oscillations and the amount of error suggests that there is some sort of noise ingress on that line. I'm afraid I can't identify anything else from the graphs though.
I think you should get your ISP involved. Send them a copy of your SNRM graph, Zen are astute enough to know that is not a normal graph and also how many Errors you are getting. I'd also send a copy of the results from the BR checker as it strengthens your case.
Good luck and please do let us know how you get on.
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OK, I think I may have a faulty modem??
After I posted my last stats I noticed that when running a ping to bbc.co.uk I was getting packet drops every 5 or 6 pings (which I guess would be consistent with all the errors).
So I decided to swap the modem out with my original Vigor 130. It's only been an hour but I've not had any packet drops and my speed test speeds have gone up.
I've been checking every few minutes and the modem is constantly reporting a SNR of 4. It's not moved at all. My only concern is that it always a whole number so is it rounding? And is it reporting the actual SNR or the desired/target SNR?
Anyway, I've posted my stats below. To my eye they look so much better with not a lot of errors?
> vdsl status
---------------------- ATU-R Info (hw: annex A, f/w: annex A/B/C) -----------
Running Mode : 17A State : SHOWTIME
DS Actual Rate : 50855000 bps US Actual Rate : 10866000 bps
DS Attainable Rate : 51535532 bps US Attainable Rate : 10848000 bps
DS Path Mode : Fast US Path Mode : Fast
DS Interleave Depth : 1 US Interleave Depth : 1
NE Current Attenuation : 22 dB Cur SNR Margin : 4 dB
DS actual PSD : 6. 6 dB US actual PSD : 13. 0 dB
NE CRC Count : 0 FE CRC Count : 116
NE ES Count : 0 FE ES Count : 107
Xdsl Reset Times : 0 Xdsl Link Times : 1
ITU Version[0] : b5004946 ITU Version[1] : 544e0000
VDSL Firmware Version : 05-07-06-0D-01-07 [with Vectoring support]
Power Management Mode : DSL_G997_PMS_L0
Test Mode : DISABLE
-------------------------------- ATU-C Info ---------------------------------
Far Current Attenuation : 34 dB Far SNR Margin : 5 dB
CO ITU Version[0] : b5004244 CO ITU Version[1] : 434da48c
DSLAM CHIPSET VENDOR : < BDCM >
> vdsl status more
---------------------- ATU-R Info (hw: annex A, f/w: annex A/B/C) -----------
Near End Far End Note
Trellis : 1 1
Bitswap : 1 1
ReTxEnable : 0 1
VirtualNoise : 0 0
20BitSupport : 0 0
LatencyPath : 0 0
LOS : 0 0
LOF : 0 0
LPR : 0 0
LOM : 0 0
SosSuccess : 0 0
NCD : 0 0
LCD : 0 0
FECS : 0 174 (seconds)
ES : 0 107 (seconds)
SES : 0 0 (seconds)
LOSS : 0 0 (seconds)
UAS : 28 1598 (seconds)
HECError : 0 0
CRC : 0 116
RsCorrection : 0 0
INP : 0 215 (symbols)
InterleaveDelay : 0 14 (1/100 ms)
NFEC : 254 32
RFEC : 16 16
LSYMB : 2918 16
INTLVBLOCK : 127 32
AELEM : 0 ----
>
> vdsl status counts
[ Counters: Showtime ]
Near End Far End Note
ElapsedTime : 5544 5544 (seconds)
CRC : 0 116
FEC : 0 174
HEC : 0 0
CRC_P : 0 0
CRCP_P : 0 0
CVP_P : 0 0
NCD : 0 0
LCD : 0 0
ES : 0 107
SES : 0 0
LOSS : 0 0
UAS : 0 0
LOFS : 0 0
[ Counters: 15Min ]
Near End Far End Note
ElapsedTime : 146 146 (seconds)
CRC : 0 0
FEC : 0 0
HEC : 0 0
CRC_P : 0 0
CRCP_P : 0 0
CVP_P : 0 0
NCD : 0 0
LCD : 0 0
ES : 0 0
SES : 0 0
LOSS : 0 0
UAS : 0 0
LOFS : 0 0
[ Counters: 1DAY ]
Near End Far End Note
ElapsedTime : 6446 6446 (seconds)
CRC : 0 116
FEC : 0 174
HEC : 0 0
CRC_P : 0 0
CRCP_P : 0 0
CVP_P : 0 0
NCD : 0 0
LCD : 0 0
ES : 0 107
SES : 0 0
LOSS : 0 0
UAS : 0 0
LOFS : 0 0
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That sync is also much better 50.8Mb compared to 46Mbps.
I note that you have 107 ES since up time of 6446 (1hr 47:25), yet none in the past 15min bin... so without doubt it has stopped.
I think I may have a faulty modem??
It's looking possible. However I have just had another thought. You havent had any power surges or power cuts have you?
I'm actually kicking myself now that I didn't suggest earlier to power down the modem and let it rest a while.
We have seen many modems which will flap after a power surge and start racking up lots of errors. It doesnt clear until you completely power down the modem.
If it was a power surge, then that would also explain why we couldn't see anything in QLN and hlog as those are taken during initialisation.
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It's looking possible. However I have just had another thought. You havent had any power surges or power cuts have you?
Now, funny you should mention that, we had a power cut last night at about 10.30pm. So that could account for all the errors this morning. But it wouldn't account for the SNR going up and down like crazy the two days before.
I've just ordered a 2nd hand HG612, so as soon as that arrives I'll plug that it and get it logging again and we can see if we get similar SNR issues.
I've just found the "Average error rates per day" text file that DSL stats produces. Here it is:
22 Aug 2018
CRC errors per hour: 32785 Down, 0.20 Up
FEC errors per hour: 7095723 Down, 0.71 Up
HEC errors per hour: 0 Down, 0 Up
ES per hour: 1913 Down, 0.20 Up
SES per hour: 746 Down, 0 Up
Total ES in the day: 18732 Down, 2 Up
21 Aug 2018
CRC errors per hour: 1511 Down, 0.72 Up
FEC errors per hour: 403075 Down, 1.22 Up
HEC errors per hour: 0 Down, 0 Up
ES per hour: 82.2 Down, 0.63 Up
SES per hour: 32.4 Down, 0 Up
Total ES in the day: 1949 Down, 16 Up
20 Aug 2018
CRC errors per hour: 0 Down, 1.05 Up
FEC errors per hour: 130038 Down, 2.59 Up
HEC errors per hour: 0 Down, 0 Up
ES per hour: 0 Down, 0.91 Up
SES per hour: 0 Down, 0 Up
Total ES in the day: 0 Down, 15 Up
[Moderator edited to fix a typo. (s/HG621/HG612)]
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we had a power cut last night at about 10.30pm. So that could account for all the errors this morning.
From the previous stats, it does look like it.
But it wouldn't account for the SNR going up and down like crazy the two days before.
It's possible if you had a surge a few days previously, yes it can cause the SNRM to flap which doesn't clear until the modem has had a full power down.
There's several times where we have seen it (even on my own line) which is why I'm kicking myself that I didn't recall earlier.
B*cat will back me up that it does occasionally occur and recommended action is to give the port time to rest.
Its perhaps also worth looking at the SNRM per Band for the downstream to see if there is any of the subtone bands more affected than the others.
I may have suggested a fresh reboot if I'd seen it was evenly spread across all 3 bands, but that's easy for me to say now with the benefit of hindsight.
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At some point in the future it may be worth just giving the Zyxel another test run before permanently ditching it in the bin, just to make sure it wasn't a power issue.
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B*cat will back me up that it does occasionally occur and recommended action is to give the port time to rest.
Yes, I agree . . . whilst also pondering why I did not think of it. :paperbag:
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And a rather belated fàilte oirbh bhuamsa since I am also in Skye, in Heasta. Welcome to the forum. ;D
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And a rather belated fàilte oirbh bhuamsa since I am also in Skye, in Heasta. Welcome to the forum. ;D
Thank you! We only moved up here in March and are loving it! And also finding that everyone is so friendly and welcoming.
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So an update on this issue as it may be useful for other people.
I put the Vigor modem back in and my connection has been rock solid. The SNR slowly went down from 6 to 3 over a few days and my connection speed has slowly gone up to 51917000bps. So I assume this is the DSLAM putting me on a 3dB profile.
Today I received my HG612, so after installing the unlocked firmware, configuring (in PPPOE bridge mode) and installing it I can now run DSL stats again. Looking at my graphs below, the SNR is now holding at 3.4dB, the QLN looks much better than before (less spikes) and even the Bitloading looks better (using a few extra tones at the end).
So either my other modem was faulty or the power outage caused an issue - either way the HG612 is giving me slightly better stats so I think I'll be sticking with it for the moment. I'll keep an eye on the errors level but at the moment it all looks OK.
One interesting thing, as I thought, the Draytek only reports whole numbers for SNR, so I still don't know if that's actual SNR or a target SNR.
Thanks for your help everyone!.
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It would be worth trying the Zyxel again at some point.
If you see the same again then the modem is duff.
As Kitz mentioned it could have been that the DSLAM port just needed a time out.
I've seen similar on Kitz line but the oscillating SNRM seemed much more uniform on her line. I believe the consensus at the time was it was an ECI DSLAM thing and I didn't spot the relevance.
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It would be worth trying the Zyxel again at some point.
If you see the same again then the modem is duff.
As Kitz mentioned it could have been that the DSLAM port just needed a time out.
Agreed. I wouldn't write it off just yet.
I've seen similar on Kitz line but the oscillating SNRM seemed much more uniform on her line. I believe the consensus at the time was it was an ECI DSLAM thing and I didn't spot the relevance.
I don't think its specific to ECI's. I've been seeing these sort of issues after power outages since the days of Maxdsl and when I was using a BTVoyager 2100 something. I'm pretty certain if you search back far enough I reported it occurring when I was having work done on the house and the electrician just switched off power at the mains rather than me doing a power down first. After coming back up it would have a hissy with SNRM jumping all over the place and a lower than normal sync. Back then it was harder to spot as there wasn't any such thing as DSLstats, but I was one of the few who recorded using custom scripts and MRTG which was a PITA to set up. :/