Kitz Forum
Broadband Related => FTTC and FTTP Issues => Topic started by: tommy45 on May 09, 2014, 08:34:26 AM
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The connection has it's self been ok, I have never noticed any issues with the link between the FTTC cab and the modem, No evidence of disconnections (loss of sync) apart from DLM intervention, Which has become more frequent in the past few months, so far dlm has only intervened 3-4 times, The first time , the standard loss of around 4-5mbps off my 80mbps sync and the added 7-8ms of latency due to interleaving, only lasted 2 days before it was fully restored again, then a gap of around 2-3mths and a repeat, except it took 14days before dlm relented, then after only around 14days it switched back to interleave again, until today again after 14 days ,
I'm currently back to fast path and my sync will most probably be back up to around 80mbps again, although the BTW IP profile refuses to update, so is currently restricting throughput when it shouldn't be, god i hate BT , I am BTW trying to buy a HG612 3B modem so i can access the stats after unlocking it ,
The connection according to my ISP is set to the BT openreach DLM "SPEED" Policy, and from what support have said , there is a small amount of errors ,which is enough to trigger DLM (into overdrive IMO) but these errors aren't having any noticeable impact on the day to day use of the connection, Hence the swapping backwards and forwards, (which is causing instability ) Surely on connections like this, dlm could be deactivated ?
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Im with you on this, most lines will handle a fair amount of errors without the EU being aware of whats going on. The line may seem a big sluggish for a while if you hit a bad period, but on the whole occasional episodes do go totally un-noticed.
Im not sure I like the idea that the BToR DLM relies so heavily on error status because its far too easy to trigger.
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Correct, Thing is though during the past 12mths is to my knowledge has never lost sync,( and i do continually monitor latency , so i would see a disconnect due to errors of REIN ect, the only times it has re synced is when i have manually rebooted or powered off the modem, oh and the DLM interventions if they count, The only issue i have noticed occasionally is the odd failed I player or ITV player stream, or when a web page doesn't load first time, gives a error the same as when the server is down 404 is it ? but on the second attempt it loads without issue, And the Poor throughput during peak times All of which aren't a conclusive indication of a issue with the connection between modem and Dslam
And having seen the results from the GEA test and another test that comprises of a TAP1 test,There is very little or nothing wrong with the actual connection it's self I have a 80/20 sync throughput is 72.50/19.8mbps
and if the reference made to margin means the noise margins then both are reported to be at 10db indicating the line could do more, which does tally with the occasional burst in speed whilst downloading some big file, I've seen 10.5 MB/s downstream and 3MB/s upstream briefly , but i will know for sure what my stats say when i eventually get a HG612 3b off ebay for what I'm willing to pay, and unlock it , it may also improve the error rate so dlm takes a chill pill
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Well i unlocked and flashed a HG612 and i've got hg612 stats running , well sort of ,
here are my stats xdslcmd info --stats
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Last initialization procedure status: 0
Max: Upstream rate = 30427 Kbps, Downstream rate = 83376 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): 7.2 15.1
Attn(dB): 13.8 0.0
Pwr(dBm): 12.4 3.8
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: 5000396 2083567
OHFErr: 38 3
RS: 0 1571828
RSCorr: 0 1334
RSUnCorr: 0 0
Bearer 0
HEC: 245 0
OCD: 5 0
LCD: 5 0
Total Cells: 1271488956 0
Data Cells: 47361004 0
Drop Cells: 0
Bit Errors: 0 0
ES: 20 3
SES: 0 0
UAS: 23 23
AS: 8271
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: 3426/3426 20/20
Total time = 2 hours 18 min 14 sec
FEC: 0 1334
CRC: 38 3
ES: 20 3
SES: 0 0
UAS: 23 23
LOS: 0 0
LOF: 0 0
LOM: 0 0
Latest 15 minutes time = 3 min 14 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
Previous 15 minutes time = 15 min 0 sec
FEC: 0 1
CRC: 15 1
ES: 6 1
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
LOM: 0 0
Latest 1 day time = 2 hours 18 min 14 sec
FEC: 0 1334
CRC: 38 3
ES: 20 3
SES: 0 0
UAS: 23 23
LOS: 0 0
LOF: 0 0
LOM: 0 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
Since Link time = 2 hours 17 min 49 sec
FEC: 0 1334
CRC: 38 3
ES: 20 3
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
LOM: 0 0
xdslcmd info --pbParams
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Last initialization procedure status: 0
Max: Upstream rate = 30427 Kbps, Downstream rate = 83376 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: 30427 kbps 83376 kbps
Actual Aggregate Tx Power: 3.8 dBm 12.4 dBm
====================================================================================
VDSL Band Status U0 U1 U2 U3 U4 D1 D2 D3
Line Attenuation(dB): 3.2 15.5 22.6 N/A N/A 8.9 19.8 30.0
Signal Attenuation(dB): 3.2 14.6 21.8 N/A N/A 11.9 19.7 30.1
SNR Margin(dB): 15.4 15.1 15.1 N/A N/A 7.2 7.2 7.2
TX Power(dBm): -11.0 -27.2 3.6 N/A N/A 8.2 7.7 7.0
Are they any good, My cab was according to the engineer around 8mths ago iirc at least 50% full, so probably close to full by now , i hope so,
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Those stats look pretty good to me.
It's a shame you didn't grab the stats 8 months ago though as you would have been able to compare recent stats against the 8 month old stats & spot what (if any) deterioration has taken place (probably reduced SNRM & reduced Attainable rates), the likely cause being increased crosstalk as more users get connected.
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I did think about getting a HG612 back then to unlock, But due to there being no DLM intervention for some 5-6mths i didn't bother, mind you so far it has only acted 3 times, the 1st time it applied interleaving and a lower sync for 2 days, (48hrs) before restoring fast path and full sync again, the other 2 occurrences where the standard min time frame of 14 days, with a period of only 14 days on full sync and fast path in between , it's been around 3weeks maybe a bit longer since it gave fast path and sync back , hopefully that was just a blip, as the time before this DLM made changes and reverted them at a different time, of 8-9am instead of the usual 5-6am , as well as a somewhat sticky bras IP profile , very odd
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I'm posting this here because i for some reason could not make a new thread , it just won't do the final bit, it stops on a plane white page ???
I think that maybe i have a developing line fault
Tonight i for the first time noticed that whilst my phone was ringing (incoming call) that both the US attainable rate and US SNR plummeted , and just before or after the the caller hung up they both returned to the levels they where before the call
UPdate i just did a QLT nothing obvious ( audible ) But i did notice a small decrease in both DS/US Attainable rates, and the DS snr from a stable 7.2 db to 7.0 , after i replaced the handset the DS Attainable and SNR shot back to their previous values again, the US Attainable has remained a little lower
here's my full stats for the past 30mins which shows the dip
Or i will when the forum will allow me to upload the stats , which on this attempt it did, weird
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It might by due to --
- A failing centralised (low-pass) filter.
- The beginnings of a HR fault.
If after removing the SSFP and substituting it with a known working micro-filter (plugged into the test socket of the NTE5/A) the drop of the US SNRM no longer occurs when the telephone is used, then you will have identified the cause of the problem.
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Thanks, so process of elimination for this one then, Although i suspect a HR fault as the SSFP as only been used for only just over 12mths,Although i know that doesn't mean a great deal, apart from it being no longer in warranty of course , should it be the SSFP which would be nice i don't have an issue replacing like for like, or i may try a MK2 SSFP,
One thing i do know it ain't my internal wiring , as there is none only the NTE no extensions
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There may, of course, be other possible causes for the effect that you are noticing . . .
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There may, of course, be other possible causes for the effect that you are noticing . . .
Well there does seem to be some interaction going on between the PSTN & VDSL , I don't doubt that it maybe something else, but without the line being tested i have no way of knowing , what else could or would be likely to cause the interaction between the services on the line ? there's not a lot i can think of but I'm not a qualified engineer , the other possibility that i can think of is battery contact or earthing issue,
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the other possibility that i can think of is battery contact or earthing issue,
Any household earthing issue's would clearly be noticeable as your fuse box circuit breaker would be tripping to the off position quite often.
Could I ask how your SNRM performs over a 24 hour period ?
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RE: Possible earthing issue , I was referring to the BT line plant, not 240v mains to save any confusion
IMO the DS SNR seems to almost flatline, The US SNR shows a bit more fluctuation, Looking at around 21:00 31/05/14 when i noticed the drop in the attainable rate ,if you look at the attenuation there's a slight disturbance visible there also on the upstream side