Broadband Related > FTTC and FTTP Issues
Line Stats
JamesK:
--- Quote from: j0hn on September 19, 2018, 03:23:17 PM ---I would set
xdslcmd configure --maxDataRate 40000 10000 100000
As your line is already at 3dB it is ok to add the cap now or anytime you like.
Seems like most lines need the cap to get to ReTx Low and so far nobody has posted back to say it has gone back to Retx High again.
--- End quote ---
Thanks j0hn. I'll probably leave it for a few days until the line settles down. This afternoon and tonight the line experienced a 3/4 minute dip in SNRM down to 1dB. The modem didn't lose sync, and it wasn't until DLM forced a resync that noticed there was a problem. I then get bumped back up to 6dB. See attachment for this evenings resync.
I'm surprised that DLM is forcing a resync, approximately 70ish minutes after the drop in SNRM, especially considering the modem isn't losing sync when this happens.
Anyone got any thoughts on this?
j0hn:
I'm going to throw a wild 1 out here...
I'm not 100% that it did set you back to a 6dB target the last time, or this time.
I've only ever seen DLM move the target SNRM in 1dB increments, up and down.
The last time your SNRM jumped back up it went up by 3dB, from the target 4dB to 7dB.
Then the next change it went down to 3dB.
If you look when it was at 6.8dB...
--- Code: ---Max: Upstream rate = 11472 Kbps, Downstream rate = 47596 Kbps
Bearer: 0, Upstream rate = 9999 Kbps, Downstream rate = 42733 Kbps
--- End code ---
That attainable suggests a 4dB target SNRM
When your target SNRM goes back to 6dB, and you sync at 6dB, the sync is just below the attainable, they match.
You haven't posted your current stats, but if I'm right then you will be synced around 44Mb, but your attainable is still around 51Mb.
A manual resync should see you return to 3dB and a sync nearer the attainable.
If I'm right about this I'm going to feel really smug lol because this is a wild shot in the dark.
Do you notice the brief 3dB drop just before the resync and 3dB increase? I believe that to be an external noise source of some kind, possibly a crosstalker?
Please post the results on info --stats if you can :)
JamesK:
--- Quote from: j0hn on September 20, 2018, 01:28:35 AM ---
If I'm right about this I'm going to feel really smug lol because this is a wild shot in the dark.
--- End quote ---
You've every right to feel smug... full stats are at the end of the post. :-)
--- Code: ---Status: Showtime
Last Retrain Reason: 1
Last initialization procedure status: 0
Max: Upstream rate = 9993 Kbps, Downstream rate = 51175 Kbps
Bearer: 0, Upstream rate = 9997 Kbps, Downstream rate = 44367 Kbps
Bearer: 1, Upstream rate = 0 Kbps, Downstream rate = 0 Kbps
--- End code ---
--- Quote ---Do you notice the brief 3dB drop just before the resync and 3dB increase? I believe that to be an external noise source of some kind, possibly a crosstalker?
--- End quote ---
I actually had a VNC desktop running to my Raspberry Pi while I was working yesterday afternoon. In all cases so far the drop has lasted for a few minutes. During that time the connection didn't drop, and I continued to be connected to the work VPN. It's then approximately 70/75 minutes later that a modem resync is forced with retrain reason 1. It's happened 3 times so far, and the resync delay is now predictable.
I agree with you that if I forced a manual resync, it would resync at 3dB.
So, if I'm still officially running with a 3dB profile, why is DLM or the modem resyncing to 6? If this carries on will DLM get to the point that it aborts 3dB completely on this line?
--- Code: (stats) ---adsl info --stats
adsl: ADSL driver and PHY status
Status: Showtime
Last Retrain Reason: 1
Last initialization procedure status: 0
Max: Upstream rate = 9993 Kbps, Downstream rate = 51122 Kbps
Bearer: 0, Upstream rate = 9997 Kbps, Downstream rate = 44367 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): 6.1 6.2
Attn(dB): 24.4 0.0
Pwr(dBm): 11.5 6.4
VDSL2 framing
Bearer 0
MSGc: -6 26
B: 227 237
M: 1 1
T: 0 43
R: 10 16
S: 0.0000 0.7565
L: 11649 2686
D: 4 1
I: 238 127
N: 238 254
Q: 4 0
V: 0 0
RxQueue: 108 0
TxQueue: 27 0
G.INP Framing: 18 0
G.INP lookback: 27 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 549718
OHFErr: 387 12
RS: 926758072 3459332
RSCorr: 436368 22
RSUnCorr: 0 0
Bearer 1
OHF: 2366879 0
OHFErr: 0 0
RS: 14200903 0
RSCorr: 427 0
RSUnCorr: 0 0
Retransmit Counters
rtx_tx: 2934723 0
rtx_c: 553681 0
rtx_uc: 83231 0
G.INP Counters
LEFTRS: 466 0
minEFTR: 44368 0
errFreeBits: 44510919 0
Bearer 0
HEC: 0 0
OCD: 0 0
LCD: 0 0
Total Cells: 3242015487 0
Data Cells: 21934048 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: 100 13
SES: 71 0
UAS: 345 56
AS: 38024
Bearer 0
INP: 52.00 0.00
INPRein: 1.00 0.00
delay: 0 0
PER: 0.00 8.16
OR: 0.01 31.35
AgR: 44464.49 10028.04
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: 11312/11312 233/233
Total time = 14 hours 2 min 12 sec
FEC: 2395135 24
CRC: 2878 13
ES: 100 13
SES: 71 0
UAS: 345 56
LOS: 1 0
LOF: 7 0
LOM: 0 0
Latest 15 minutes time = 2 min 12 sec
FEC: 11 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: 120 1
CRC: 0 1
ES: 0 1
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
LOM: 0 0
Latest 1 day time = 14 hours 2 min 12 sec
FEC: 2395135 24
CRC: 2878 13
ES: 100 13
SES: 71 0
UAS: 345 56
LOS: 1 0
LOF: 7 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 = 10 hours 33 min 43 sec
FEC: 436368 22
CRC: 387 12
ES: 19 12
SES: 14 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
LOM: 0 0
NTR: mipsCntAtNtr=0 ncoCntAtNtr=0
--- End code ---
j0hn:
--- Quote from: JamesK ---You've every right to feel smug... full stats are at the end of the post. :-)
--- End quote ---
j0hn sets mode to +smug :dance:
So you have a noise source that comes on briefly, and knocks the actual SNRM down by 3dB.
In the 2 examples you posted it lasted about 1 min and about 5 minutes in the 2nd example.
Then about 70-75 mins later it triggers a resync, and the 3dB noise is present during the resync/training causing you to sync 3dB lower than the target SNRM.
The strange thing is it looks like this noise source is gone by the time DslStats does the first sample after sync is achieved. The actual SNRM immediately has 3dB "spare".
Very very strange indeed.
Are you still on the HG612? I wonder if it could be a problem with the modem. Might be a good time to try that Zyxel modem!
What you could do is set a email alert in DslStats to email you if the downstream SNRM drops below x.
As you're at 6dB I would set it to about 4dB.
It will email you 70-75 minutes before the resync will come when the SNRM drops for the brief period.
--- Quote from: James ---If this carries on will DLM get to the point that it aborts 3dB completely on this line?
--- End quote ---
Do you get a burst of ES or LEFTERS during the brief SNRM crash?
DLM is unlikely to take action on the line for a single resync every few days.
You could either take the line down for 10 minutes at around 70 minutes after DslStats emails you, though not ideal.
It should also be safe to resync the line after it comes back up at 6dB. DLM won't take action on that if it's the only resync that day. Again that's not ideal.
Does anyone else have any opinions on what could cause SNRM to drop by 3dB for 1-5 mins, then 70-75 minutes later it causes the line to resync, coming back up 3dB higher than the target SNRM?
JamesK:
--- Quote from: j0hn on September 20, 2018, 01:16:24 PM ---Are you still on the HG612? I wonder if it could be a problem with the modem. Might be a good time to try that Zyxel modem!
--- End quote ---
After the resync yesterday afternoon, I needed to go out. So I took the opportunity to power off the HG612. When I got back an hour later, I installed the preconfigured Zyxel. As expected on resync it went to 3dB. There were two drops early evening. One was at around 17:40, and the other at 18:50. I was was watching for a resync at around 18:55/19:00 based on the 1st drop, but it didn't happen. However, just after 20:00 it did resync, which was approx 70mins after the 18:50 drop.
--- Quote ---What you could do is set a email alert in DslStats to email you if the downstream SNRM drops below x.
As you're at 6dB I would set it to about 4dB.
--- End quote ---
Good idea. I'll set DSLstats to do that, although at the moment it doesn't like the SMTP login for either my btinternet or google accounts.
--- Quote ---Do you get a burst of ES or LEFTERS during the brief SNRM crash?
--- End quote ---
I've not looked at that... What's the best way of determining that from DSLstats?
Since the resync last night, DLM hasn't forced another resync to bring it back to the 3dB profile. This is what happened previously at around 4am the next day.
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