From the unlocked HG612 modem's GUI, these are my current details:-
In case anyone is still listening to the real thread, rather than arguing over the meaning of SNR, I've come across something of a hitch...
That is that the HG612
is not reporting error data consistently!
As far as I can make out, the
GUI reports CRC, FEC and HEC by taking values from the "xdslcmd info --show" command, extracting the data as follows:
- CRC comes from the "RSUnCorr" field
- FEC comes from the "OHFErr" field (I have no idea what this is. Some kind of framing error?)
- HEC comes from the "HEC" field
However, the "xdslcmd info --stats" command gives different information (but is not quite correct about some of the presentation).
The last section of the "stats" is labelled "Since Link Time" (in my case, currently 14 days), and gives FEC, CRC and ES values that I can believe. These seem to be the statistics since the last synchronisation.
The prior 4 sections of stats give the stats for smaller, more recent periods (days and 15 mins). They too look consistent.
The prior section (labelled "Total Time") also gives statistics that i believe are valid since the modem was last booted. However, it then goes on to display a time that patently *isn't* the total time the the modem has been on - but the corresponding statistics do seem to represent the full set. In my case, the full uptime is just over 16 days, the "total time" is reported as just over a day, but the numbers in the statistics are higher than the later "14 day" numbers. In fact, the numbers I see *do* reflect the burst of errors I got in the 1st 2 days, which cause DLM to resync me with interleaving... which resulted in far fewer CRC errors (and ES) and far higher FEC.
So which numbers should we believe?
Here are my numbers from the different sources:
GUI
Text |
1
23
45
67
89
1011
| DSL up time 1229823 (14 days 05:37:03)
Attainable rate (kbit/s) 59256 16780
SNR margin (dB) 10.1 11.3Line attenuation (dB) 0 0
Output power (dBmV) 12.3 6.6
Line rate (kbit/s) 39996 10000 CRC errors 11155 0
FEC errors 331 288HEC errors 2987 0 |
xdslcmd info --show
Text |
1
23
45
67
89
1011
1213
1415
1617
1819
2021
2223
2425
2627
2829
3031
3233
3435
3637
3839
4041
4243
4445
4647
4849
5051
5253
5455
5657
58 | # xdslcmd info --show
xdslcmd: ADSL driver and PHY statusStatus: Showtime
Retrain Reason: 2Max: Upstream rate = 16758 Kbps, Downstream rate = 59256 Kbps
Path: 0, Upstream rate = 10000 Kbps, Downstream rate = 39996 Kbps
Link Power State: L0Mode: VDSL2 Annex B
VDSL2 Profile: Profile 17aTPS-TC: PTM Mode
Trellis: U:ON /D:ONLine Status: No Defect
Training Status: Showtime Down Up
SNR (dB): 10.1 11.3Attn(dB): 0.0 0.0
Pwr(dBm): 12.3 6.6 VDSL2 framing
Path 0B: 57 111
M: 1 2T: 64 50
R: 16 16S: 0.0461 0.7101
L: 12835 2704D: 701 1
I: 74 120N: 74 240
Counters Path 0
OHF: 553649999 656045OHFErr: 331 288
RS: 3221633228 3957556RSCorr: 6819414 1551
RSUnCorr: 11155 0
Path 0HEC: 2987 0
OCD: 0 0LCD: 0 0
Total Cells: 140396837 0Data Cells: 453789795 0
Drop Cells: 0Bit Errors: 0 0
ES: 6235 302
SES: 8 0UAS: 35 35
AS: 1230559
Path 0INP: 3.00 0.00
PER: 2.21 8.87delay: 8.00 0.00
OR: 86.72 55.88
Bitswap: 33420 10345 |
xdslcmd info --stats
Text |
1
23
45
67
89
1011
1213
1415
1617
1819
2021
2223
2425
2627
2829
3031
3233
3435
3637
3839
4041
4243
4445
4647
4849
5051
5253
5455
5657
5859
6061
6263
6465
6667
6869
7071
7273
7475
7677
7879
8081
8283
8485
8687
8889
9091
9293
9495
9697
9899
100101
102103
104105
106107
| # xdslcmd info --stats
xdslcmd: ADSL driver and PHY statusStatus: Showtime
Retrain Reason: 2Max: Upstream rate = 16780 Kbps, Downstream rate = 59256 Kbps
Path: 0, Upstream rate = 10000 Kbps, Downstream rate = 39996 Kbps
Link Power State: L0Mode: VDSL2 Annex B
VDSL2 Profile: Profile 17aTPS-TC: PTM Mode
Trellis: U:ON /D:ONLine Status: No Defect
Training Status: Showtime Down Up
SNR (dB): 10.1 11.3Attn(dB): 0.0 0.0
Pwr(dBm): 12.3 6.6 VDSL2 framing
Path 0B: 57 111
M: 1 2T: 64 50
R: 16 16S: 0.0461 0.7101
L: 12835 2704D: 701 1
I: 74 120N: 74 240
Counters Path 0
OHF: 553684194 664617OHFErr: 331 288
RS: 3228198526 91119RSCorr: 6819524 1551
RSUnCorr: 11155 0
Path 0HEC: 2987 0
OCD: 0 0LCD: 0 0
Total Cells: 146241308 0Data Cells: 453791806 0
Drop Cells: 0Bit Errors: 0 0
ES: 6235 302
SES: 8 0UAS: 35 35
AS: 1230635
Path 0INP: 3.00 0.00
PER: 2.21 8.87delay: 8.00 0.00
OR: 86.72 55.88
Bitswap: 33420 10345
Total time = 1 days 2 hours 5 min 24 secFEC: 6819524 1703
CRC: 331 329ES: 6235 302
SES: 8 0UAS: 35 35
LOS: 5 0LOF: 5 0
Latest 15 minutes time = 5 min 24 secFEC: 435 0
CRC: 0 0ES: 0 0
SES: 0 0UAS: 0 0
LOS: 0 0LOF: 0 0
Previous 15 minutes time = 15 min 0 secFEC: 1104 1
CRC: 0 1ES: 0 1
SES: 0 0UAS: 0 0
LOS: 0 0LOF: 0 0
Latest 1 day time = 2 hours 5 min 24 secFEC: 11260 12
CRC: 0 3ES: 0 3
SES: 0 0UAS: 0 0
LOS: 0 0LOF: 0 0
Previous 1 day time = 24 hours 0 secFEC: 403855 111
CRC: 35 21ES: 11 21
SES: 0 0UAS: 0 0
LOS: 0 0LOF: 0 0
Since Link time = 14 days 5 hours 50 min 35 secFEC: 6819524 1551
CRC: 331 288ES: 114 263
SES: 0 0UAS: 0 0
LOS: 0 0LOF: 0 0 |
I always thought "FEC" statistics were the same as "RSCorr". These are the number of RS blocks that could be corrected by the FEC process, so are a count of teh number of correctable errors encountered. In ADSL, FEC is turned off when interleaving is off - so FEC would be zero. I guess FTTC/VDSL2 is the same.
I also always thought that the "RSUncorr" were the errors (uncorrectable by the FEC process) that therefore caused both CRC and HEC. However, RS blocks occur at a far greater rate than the CRC blocks, so you expect RSUnCorr to be the maximum of CRC+HEC. If RSUnCorr errors happen in bursts, then you might even expect 1 CRC (or HEC) per 16 RSUnCorr; if the RSUnCorr occur in a very spread-out fashion, then you'd get 1 CRC (or HEC) per RSUnCorr.
Looking at the overall output, I think the GUI ought to be reporting these values (or something like them):
CRC: 331
FEC: 6819524
HEC: 2987
However, I'm not fully convinced about the "CRC" figure here. I would have to monitor for longer.
I'm a little busy at the moment, so if I don't immediately answer any responses, you'll know why