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deleted
(deleted) Fri 30-Nov-18 20:36:07

SNR Per Tone Graph

[link to this post]

Hi everyone!

I've compared my line's SNR Per Tone graph between when it experiences occasional DS SNRM drops and doesn't. I've noticed that most DS tones above 332 (1431 kHz) are impacted when this occurs. Does anyone know what could be causing this?

Thanks!

Will

During drop: https://prnt.sc/lp4w9q

Normal: https://prnt.sc/lp4xko

Edited by deleted (Fri 30-Nov-18 21:29:07)

RobertoS
(elder) Sat 01-Dec-18 00:57:51

Re: SNR Per Tone Graph

[re: deleted] [link to this post]

The SNRM drops because the graphed data is lower wink

. Not the other way round as your post implies.

The graphed data is lower because the noise is greater.

This effect has been known since ADSL was invented smile

. It�s why we monitor SNRM, as that�s what it tells us just by looking at the stats in the modern.

The purpose of the graphs you posted is to show up unusual patterns compared to the particular line�s usual one, or compared to other �normal� lines. Your two patterns are basically identical, suggesting there is nothing odd going on. There are known causes of many short stretches of such graphs having consistent unusual or sudden short gaps or very low values, so helping problem diagnosis.

The standard SNRM graph is more useful day to day, enabling you to spot time-patterns for significant drops other than the expected night-time ones. Then you might find the SNR per tone ones for the precise times affected useful.

My broadband basic info/help site - www.robertos.me.uk. Domains, site and mail hosting - Tsohost.
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deleted
(deleted) Sat 01-Dec-18 10:26:46

Re: SNR Per Tone Graph

[re: RobertoS] [link to this post]

Thanks, Bob. If you look closely though, they are far from identical. Here's the SNRM plot for the last 24 hours, as you can see it's a mess. I have posted my line stats, too. Each time there is a DS SNRM "spike" the tone graph is virtually the same.

http://prntscr.com/lpaw6l

Text

adsl info --stats
adsl: ADSL driver and PHY statusStatus: Showtime
Last Retrain Reason:    0Last initialization procedure status:   0
Max:    Upstream rate = 8558 Kbps, Downstream rate = 53014 KbpsBearer: 0, Upstream rate = 8589 Kbps, Downstream rate = 52438 Kbps
Bearer: 1, Upstream rate = 0 Kbps, Downstream rate = 0 KbpsLink Power State:       L0
Mode:                   VDSL2 Annex BVDSL2 Profile:          Profile 17a
TPS-TC:                 PTM Mode(0x0)Trellis:                U:ON /D:ON
Line Status:            No DefectTraining Status:        Showtime
                Down            UpSNR (dB):        3.8             5.0
Attn(dB):        26.2            0.0Pwr(dBm):        12.0            5.4
                         VDSL2 framing
                        Bearer 0MSGc:           -6              -6
B:              227             227M:              1               1
T:              0               0R:              10              10
S:              0.1383          0.8443L:              13768           2255
D:              4               4I:              238             238
N:              238             238Q:              4               4
V:              0               0RxQueue:                125             15
TxQueue:                25              5G.INP Framing:          18              18
G.INP lookback:         25              5RRC bits:               24              24
                        Bearer 1MSGc:           122             58
B:              0               0M:              2               2
T:              2               2R:              16              16
S:              8.0000          16.0000L:              32              16
D:              1               1I:              32              32
N:              32              32Q:              0               0
V:              0               0RxQueue:                0               0
TxQueue:                0               0G.INP Framing:          0               0
G.INP lookback:         0               0RRC bits:               0               0
                         Counters
                        Bearer 0OHF:            0               0
OHFErr:         567             0RS:             3995588552              2069552738
RSCorr:         152799634               8789RSUnCorr:       0               0
                        Bearer 1OHF:            27194957                27305688
OHFErr:         0               3RS:             217559159               109222753
RSCorr:         118522          133RSUnCorr:       0               0
                         Retransmit Counters
rtx_tx:         1311299         10574rtx_c:          1176138         722
rtx_uc:         1722            0 
                        G.INP CountersLEFTRS:         209             54
minEFTR:        52404           8582errFreeBits:    349131341               57102151
                         Bearer 0
HEC:            0               0OCD:            0               0
LCD:            0               0Total Cells:    1081369746              0
Data Cells:     525612005               0Drop Cells:     0
Bit Errors:     0               0 
                        Bearer 1HEC:            0               0
OCD:            0               0LCD:            0               0
Total Cells:    0               0Data Cells:     0               0
Drop Cells:     0Bit Errors:     0               0
 ES:             45              0
SES:            20              0UAS:            124             124
AS:             436891 
                        Bearer 0INP:            54.00           47.00
INPRein:        1.00            0.00delay:          0               0
PER:            0.00            0.00OR:             0.01            0.01
AgR:            52552.76        8607.38 
                        Bearer 1INP:            2.00            4.00
INPRein:        2.00            4.00delay:          0               0
PER:            16.06           16.06OR:             63.75           31.87
AgR:            63.75   31.87 
Bitswap:        220863/239847           1733/1757 
Total time = 5 days 1 hours 23 min 35 secFEC:            152799634               8789
CRC:            567             0ES:             45              0
SES:            20              0UAS:            124             124
LOS:            0               0LOF:            0               0
LOM:            0               0Retr:           0
FailedRetr:     0FailedFastRetr: 0
Latest 15 minutes time = 8 min 35 secFEC:            41806           0
CRC:            17              0ES:             1               0
SES:            0               0UAS:            0               0
LOS:            0               0LOF:            0               0
LOM:            0               0Retr:           0
FailedRetr:     0FailedFastRetr: 0
Previous 15 minutes time = 15 min 0 secFEC:            26565           6
CRC:            0               0ES:             0               0
SES:            0               0UAS:            0               0
LOS:            0               0LOF:            0               0
LOM:            0               0Retr:           N/A
FailedRetr:     N/AFailedFastRetr: N/A
Latest 1 day time = 1 hours 23 min 35 secFEC:            641163          28
CRC:            17              0ES:             1               0
SES:            0               0UAS:            0               0
LOS:            0               0LOF:            0               0
LOM:            0               0Retr:           0
FailedRetr:     0FailedFastRetr: 0
Previous 1 day time = 24 hours 0 secFEC:            26624694                1414
CRC:            411             0ES:             17              0
SES:            12              0UAS:            0               0
LOS:            0               0LOF:            0               0
LOM:            0               0Retr:           0
FailedRetr:     0FailedFastRetr: 0
Since Link time = 5 days 1 hours 21 min 31 secFEC:            152799634               8789
CRC:            567             0ES:             45              0
SES:            20              0UAS:            0               0
LOS:            0               0LOF:            0               0
LOM:            0               0Retr:           0
FailedRetr:     0FailedFastRetr: 0
NTR: mipsCntAtNtr=0 ncoCntAtNtr=0 >

Edited by deleted (Sat 01-Dec-18 10:28:45)

RobertoS
(elder) Sat 01-Dec-18 10:42:49

Re: SNR Per Tone Graph

[re: deleted] [link to this post]

Yes, I was tired re the shapes being virtually identical. They seemed at the time to move up and down together but now I see parts don�t.

What you also need to look at is

adsl info �pBparams

when normal and when low.

deleted
(deleted) Sat 01-Dec-18 10:47:05

Re: SNR Per Tone Graph

[re: RobertoS] [link to this post]

Thanks, Bob. Would you say if parts don't, then it's interference from an electrical item?

Have looked at the pbParams, and the only values that change are the SNRM per band values, which are graphed here: http://prntscr.com/lpb3uc

Edited by deleted (Sat 01-Dec-18 10:53:53)

RobertoS
(elder) Sat 01-Dec-18 11:14:10