Line stats

Hi all,

I have posted my line stats to gain some insight into whether or not my sync rate is any good compared to the snr and the line attenuation. Is an Attn of 20.3dB about right for being about 300 meters from my cabinet?


# xdslcmd info --stats
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Last initialization procedure status: 0
Max: Upstream rate = 14508 Kbps, Downstream rate = 50240 Kbps
Bearer: 0, Upstream rate = 11999 Kbps, Downstream rate = 44000 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): 8.6 7.8
Attn(dB): 20.3 0.0
Pwr(dBm): 13.8 7.5
VDSL2 framing
Bearer 0
MSGc: -6 58
B: 154 236
M: 1 1
T: 0 27
R: 10 16
S: 0.1118 0.6291
L: 11803 3230
D: 16 1
I: 165 127
N: 165 254
Q: 16 0
V: 8 0
RxQueue: 27 0
TxQueue: 9 0
G.INP Framing: 18 0
G.INP lookback: 9 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 1808040
OHFErr: 0 362
RS: 1631559904 1086004
RSCorr: 32149 1880
RSUnCorr: 0 0
Bearer 1
OHF: 10356295 0
OHFErr: 0 0
RS: 62137401 0
RSCorr: 36 0
RSUnCorr: 0 0

Retransmit Counters
rtx_tx: 76764 0
rtx_c: 1447 0
rtx_uc: 0 0

G.INP Counters
LEFTRS: 22 0
minEFTR: 44002 0
errFreeBits: 111618854 0

Bearer 0
HEC: 0 0
OCD: 0 0
LCD: 0 0
Total Cells: 1190587707 0
Data Cells: 432687885 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: 0 354
SES: 0 0
UAS: 20 20
AS: 166350

Bearer 0
INP: 46.00 0.00
INPRein: 0.00 0.00
delay: 0 0
PER: 0.00 8.52
OR: 0.01 60.05
AgR: 44178.09 12059.03

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: 100811/100811 265/265

Total time = 1 days 22 hours 12 min 50 sec
FEC: 32149 1880
CRC: 0 362
ES: 0 354
SES: 0 0
UAS: 20 20
LOS: 0 0
LOF: 0 0
LOM: 0 0
Latest 15 minutes time = 12 min 50 sec
FEC: 160 10
CRC: 0 2
ES: 0 2
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
LOM: 0 0
Previous 15 minutes time = 15 min 0 sec
FEC: 117 10
CRC: 0 0
ES: 0 0
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
LOM: 0 0
Latest 1 day time = 22 hours 12 min 50 sec
FEC: 16975 894
CRC: 0 171
ES: 0 167
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
LOM: 0 0
Previous 1 day time = 24 hours 0 sec
FEC: 15174 986
CRC: 0 191
ES: 0 187
SES: 0 0
UAS: 20 20
LOS: 0 0
LOF: 0 0
LOM: 0 0
Since Link time = 1 days 22 hours 12 min 29 sec
FEC: 32149 1880
CRC: 0 362
ES: 0 354
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
LOM: 0 0

I'm on infinity 2 which states the top down speed is 76Mb . Don't think i'm ever going to get close to this! . However since G.inp has been on the line my sync rate has gone from 39998 to 44000

Don't know about the distance but your speed seems in the right range for the attenuation.

It looks like your sync speed has been capped by DLM to raise the SNR margin above the target of 6. This often is a result of disconnections on your line.

I see your uptime is less than 2 days, which may be due to a line fault or suspect extension wiring. If you can find a way to increase your uptime, DLM should respond by uncapping your speed so the sync will rise closer to the max rate.

Attenuation is way too high for a 300m line, you should be expecting something more in the 10 to 12 dB region.

How have you measured the 300m? Straight line, estimated along the roads? Actual cable length strung pole to pole? If you know or can identify the route, it is from you to the original PCP and from there to the Fibre twin.

What does the BT Checker at http://www.dslchecker.bt.com/adsl/adslchecker.welcome suggest for you and your immediate neighbours?

I thought the attenuation was high too. Here are the figures;

Fttc range (clean)
69.8 (high)
49.9 (low)

Fttc range (impacted)
60.1 (high)
35 (low)

A neighbours have the same figures.

I measured the line using a tomtom from my house to the fibre cab. The pcb is not that far from the fibre cab.
Its a relatively new housing estate (4 years old) so you wouldn't of thought there would be any faults on the line.

You make that sound as if the PCP is further away than the FTTC. In which case it is still distance to the PCP plus the distance between them. You get to the FTTC through the PCP, not the other way round.

Those estimates might suggest a 20dB attenuation which itself points to a line of maybe 500 to 600 metres. You need an accurate measurement of where the line runs from house, to pole, to next pole ... to underground, to PCP, then back to Fibre Cab.

Confirming RobertoS's comment.

"My" FTTC (Fibre) Cabinet is physically about 10 Metres from my front door, where the phone line comes in.

Similarly, the FTTC is about 40 Metres from the PCP, which in turn is about 50 Metres from my front door.

The above are all the "obvious, simple" physical/geographical distances.

BUT

The actual copper-wire distance from my front door to the FTTC, is about 300 Metres, made up of 250 Metres, front door to PCP (1967 vintage), plus 50 Metres from the PCP to the FTTC.

An irony of it is that although the FTTC is physically about 40 Metres from the PCP, the associated links, leave the FTTC and proceed in the opposite direction away from the PCP, to reach and Under-Ground Chamber, where they do an "about-turn" going back past the FTTC on their way to the PCP!

It was a "green-field site" when built in 1967, with Phone wiring laid in underground to every house, so why the lengthy run is not clear - maybe copper was relatively cheap in those days.

As virtually all of the wiring, old and new, is underground, very little of it is directly traceable, above ground, so generally "Tom-Tom" distances etc are of little use, unless you know where the wires actually run.

=========

My Downstream Line Attenuation is presently 13.4 db, on a "clean" line, ie only a very slight hum heard on a Quiet Line Test.

I regularly get 37+ Mbps on a 40/10 contract.