Kitz ADSL Broadband Information
adsl spacer  
Support this site
Home Broadband ISPs Tech Routers Wiki Forum
 
     
   Compare ISP   Rate your ISP
   Glossary   Glossary
 
Please login or register.

Login with username, password and session length
Advanced search  

News:

Pages: [1] 2 3

Author Topic: High Target SNR.  (Read 1301 times)

xreyuk

  • Reg Member
  • ***
  • Posts: 124
High Target SNR.
« on: December 14, 2018, 11:04:50 AM »

Hi All,

For around the past year or so, my FTTC connection has been running at an SNR on the downstream of 21.9dBm, with speeds of 41Mbps. I ended up having to reboot the modem the other night (I still use a HG612) and to my surprise resynced at 51Mbps and an SNR of 6dBm.

My connection stayed stable for 24 hours, no problems, minimal errors (although some) and I was enjoying the speed increase. Last night the line decided to resync itself (I assume to DLM) at resynced around 41Mbps, with an SNR of 21.9dBM again, so I would suggest for some reason this is what my target is set at.

I am with Plusnet, is there anything they, or I can do regarding this?

As a side note, I'm thinking about getting a new updated modem (or router for bridge mode), can anyone advise if it's worth it, and I'm likely to see any gain from it?
Logged

jelv

  • Helpful
  • Kitizen
  • *
  • Posts: 1234
Re: High Target SNR.
« Reply #1 on: December 14, 2018, 11:07:50 AM »

Have you been monitoring the errors?
Logged
Line rental: Pulse8, Broadband: AAISP Home::1 FTTC 80/20, Mobile: id Mobile

xreyuk

  • Reg Member
  • ***
  • Posts: 124
Re: High Target SNR.
« Reply #2 on: December 14, 2018, 12:24:40 PM »

Have you been monitoring the errors?

Yes, there were some errors on the downstream, but nothing ridiculous. Even with the 22 SNR, I have a few errors, but there's hardly anything between the 6dBm SNR and 22dBm SNR.

The upstream errors like crazy, because for some reason the SNR is 0.
Logged

jelv

  • Helpful
  • Kitizen
  • *
  • Posts: 1234
Re: High Target SNR.
« Reply #3 on: December 14, 2018, 01:14:58 PM »

Have you checked the phone line using the quiet line test?
Logged
Line rental: Pulse8, Broadband: AAISP Home::1 FTTC 80/20, Mobile: id Mobile

ejs

  • Kitizen
  • ****
  • Posts: 1837
Re: High Target SNR.
« Reply #4 on: December 14, 2018, 04:09:35 PM »

The only target SNRM values on FTTC are 6, 5, 4 and 3 dB. The DLM can also apply rate caps to make your line connect at a lower speed and with higher SNRM than those target SNRM values. If the DLM is not capping the rate, then there must be some cause other than the DLM.
Logged

j0hn

  • Kitizen
  • ****
  • Posts: 2165
Re: High Target SNR.
« Reply #5 on: December 14, 2018, 05:15:37 PM »

It's hard to tell without detailed stats, and the Plusnet Hub is very limited with its stats.

Can you post all the stats that it does give, exactly as it gives them.

It could be that the line was banded (capped), this was removed, then reapplied, but I find that extremely unlikely.

Can you follow this guide here
FTTC cab - How to lookup location & type of DSLAM
and check what type of DSLAM you are connected to, ECI or Huawei.

Alternatively tell us the cabinet and exchange and we can look it up for you.
Logged
Plusnet FTTC 80/20 -  ECI now Huawei cab
retx low @ 3dB target SNRM
Zyxel VMG1312-B10A bridged with 1508 MTU + Asus RT-AC68U running Asuswrt-Merlin

xreyuk

  • Reg Member
  • ***
  • Posts: 124
Re: High Target SNR.
« Reply #6 on: December 16, 2018, 10:52:30 PM »

Hi all,

Thanks for the replies.

I hadn't done the quiet line test, so did one today and it reveals faint buzzing and popping noises.

What other causes than the DLM could be causing the 22dBm SNR?

I am not using the plusnet hub, I am still connected using an unlocked Huawei HG612. Here are the current line stats. As for cabinet, I am connected to a Huawei cab. Plusnet have said that I am not banded.

Code: [Select]
# xdslcmd info --show

xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 1
Last initialization procedure status: 0
Max: Upstream rate = 10800 Kbps, Downstream rate = 51480 Kbps
Bearer: 0, Upstream rate = 10800 Kbps, Downstream rate = 41031 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): 8.0 6.5
Attn(dB): 21.9 0.0
Pwr(dBm): 12.0 6.6
VDSL2 framing
Bearer 0
MSGc: -6 26
B: 227 237
M: 1 1
T: 0 48
R: 10 16
S: 0.1767 0.7004
L: 10773 2901
D: 4 1
I: 238 127
N: 238 254
Q: 4 0
V: 0 0
RxQueue: 100 0
TxQueue: 20 0
G.INP Framing: 18 0
G.INP lookback: 20 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 212441
OHFErr: 677 18
RS: 1931391808 3850590
RSCorr: 252967 184
RSUnCorr: 0 0
Bearer 1
OHF: 5333665 0
OHFErr: 0 0
RS: 32001619 0
RSCorr: 4 0
RSUnCorr: 0 0

Retransmit Counters
rtx_tx: 216107069 0
rtx_c: 4061965 0
rtx_uc: 370050 0

G.INP Counters
LEFTRS: 967 0
minEFTR: 41027 0
errFreeBits: 701718282 0

Bearer 0
HEC: 0 0
OCD: 0 0
LCD: 0 0
Total Cells: 2463921243 0
Data Cells: 43592669 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: 150 53
SES: 62 0
UAS: 128 77
AS: 85673

Bearer 0
INP: 55.00 0.00
INPRein: 1.00 0.00
delay: 0 0
PER: 0.00 8.43
OR: 0.01 30.33
AgR: 41120.78 10830.73

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: 58220/58220 1383/1383

*edit*

Looking at these stats it appears I'm connected with an SNR margin of 8 (which is still high) however, it appears the numbers may have been showing in the incorrect places on the GUI. So don't I feel like a tool.

However, the main issue is that I've been having problems with gaming and some streaming, and by the looks of it I'm running errors on my line. Couple that with the noisy quiet line test, could there be a fault on my line?
« Last Edit: December 16, 2018, 10:59:04 PM by xreyuk »
Logged

xreyuk

  • Reg Member
  • ***
  • Posts: 124
Re: High Target SNR.
« Reply #7 on: December 16, 2018, 11:15:24 PM »

These are the stats after doing a reboot this evening, I can update these after around 24 hours to see how things are going if that's a good idea? As you can see, sync speed jumped massively.

Code: [Select]
# xdslcmd info --show

xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Last initialization procedure status: 0
Max: Upstream rate = 10819 Kbps, Downstream rate = 55168 Kbps
Bearer: 0, Upstream rate = 10819 Kbps, Downstream rate = 55378 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): 3.3 6.5
Attn(dB): 21.9 0.0
Pwr(dBm): 12.8 6.7
VDSL2 framing
Bearer 0
MSGc: -6 26
B: 227 237
M: 1 1
T: 0 48
R: 10 16
S: 0.1309 0.6992
L: 14540 2906
D: 4 1
I: 238 127
N: 238 254
Q: 4 0
V: 0 0
RxQueue: 135 0
TxQueue: 27 0
G.INP Framing: 18 0
G.INP lookback: 27 0
RRC bits: 0 24
Bearer 1
MSGc: 122 -6
B: 0 0
M: 2 0
T: 2 0
R: 16 0
S: 8.0000 0.0000
L: 32 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 19671
OHFErr: 0 0
RS: 4990084 944114
RSCorr: 37862 0
RSUnCorr: 0 0
Bearer 1
OHF: 10272 0
OHFErr: 0 0
RS: 81680 0
RSCorr: 0 0
RSUnCorr: 0 0

Retransmit Counters
rtx_tx: 216107941 0
rtx_c: 745 0
rtx_uc: 136 0

G.INP Counters
LEFTRS: 0 0
minEFTR: 55353 0
errFreeBits: 139236 0

Bearer 0
HEC: 0 0
OCD: 0 0
LCD: 0 0
Total Cells: 17531469 0
Data Cells: 26503 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 0
SES: 0 0
UAS: 26 26
AS: 165

Bearer 0
INP: 56.00 0.00
INPRein: 1.00 0.00
delay: 0 0
PER: 0.00 8.42
OR: 0.01 30.39
AgR: 55499.50 10849.39

Bearer 1
INP: 2.00 0.00
INPRein: 2.00 0.00
delay: 0 0
PER: 16.06 0.01
OR: 63.75 0.01
AgR: 63.75 0.01

Bitswap: 120/120 6/6

#
Logged

kitz

  • Administrator
  • Senior Kitizen
  • *
  • Posts: 31799
  • Trinity: Most guys do.
    • http://www.kitz.co.uk
Re: High Target SNR.
« Reply #8 on: December 16, 2018, 11:30:55 PM »

Quote
at an SNR on the downstream of 21.9dBm, with speeds of 41Mbps.

21.9dBm is the attenuation. 

I note one of your recent sync's shows SNR (dB):   3.3   which indicates that DLM could have moved you to Target SNRM of 3dB.  This would account for the jump to 55Mbps.

The alternative is you are still on a Target 6dB but one of your crosstalkers could have been offline when you did a resync.  If all lines on the DSLAM are forced to resync it's not uncommon if your modem comes up before theirs to get a speed boost, but the SNRM will shoot back down when they come online.
If I sync before my neighbour then I get a speed boost of circa 12Mbps, but as soon as their modem syncs then my SNRM drops to 3.2dB.
Logged
Please do not PM me with queries for broadband help as I may not be able to respond.
-----
How to get your router line stats :: ADSL Exchange Checker

burakkucat

  • Global Moderator
  • Senior Kitizen
  • *
  • Posts: 25019
  • Over the Rainbow Bridge
    • The ELRepo Project
Re: High Target SNR.
« Reply #9 on: December 16, 2018, 11:52:50 PM »

21.9dBm is the attenuation.

Huh?  ???  Something expressed as decibels relative to one milliwatt is the power. I suspect that there was "eye-on-line slippage" when initially reading the values.

            Down      Up
SNR (dB):    3.3      6.5
Attn(dB):   21.9      0.0
Pwr(dBm):   12.8      6.7

Considering those three lines it looks, to me, as if the value on the second line was taken as the value of the first line with the units of the third line!
Logged
:cat:  100% Linux and, previously, Unix. Co-founder of the ELRepo Project.

Please consider making a donation to support the running of this site.

xreyuk

  • Reg Member
  • ***
  • Posts: 124
Re: High Target SNR.
« Reply #10 on: December 17, 2018, 01:53:54 AM »

21.9dBm is the attenuation. 

I note one of your recent sync's shows SNR (dB):   3.3   which indicates that DLM could have moved you to Target SNRM of 3dB.  This would account for the jump to 55Mbps.

The alternative is you are still on a Target 6dB but one of your crosstalkers could have been offline when you did a resync.  If all lines on the DSLAM are forced to resync it's not uncommon if your modem comes up before theirs to get a speed boost, but the SNRM will shoot back down when they come online.
If I sync before my neighbour then I get a speed boost of circa 12Mbps, but as soon as their modem syncs then my SNRM drops to 3.2dB.

Yeah for some reason the GUI reports the attenuation value as the SNR value (I was checking the GUI first, this is the first time Iíve actually used the telnet stats in a while!).

Thanks for the info about crosstalk. This reboot this evening was caused by me (power at home) so all of the others would have been synced (unless I got really lucky). However what I tend to find is the line will hold sync perfectly fine at those stats (with errors) then DLM will cause a resync after 24 hours when it hits midnight (so I resync at 9PM manually then DLM does it 27 hours later). I can pretty much guarantee this is what will happen in this case.

I wouldnít mind the speed drop from 52Mbps to 41Mbps if I actually gained any stability out of it but I donít. Iím suffering frequent disconnections whilst gaming, and struggle with live IPTV services.

My thinking is, if Iím going to have the problems regardless what speed Iím at, Iíd rather be at the faster speed.

Iíve tried raising a fault with plusnet before about the problems with service, but they just quote that Iím still running at the expected numbers (between 36-54Mbps) and seem to ignore the stability issues.

Iíve ruled out all local equipment because these issues have been going on so long, all my equipment has changed (apart from the modem).
Logged

Chrysalis

  • Content Team
  • Addicted Kitizen
  • *
  • Posts: 5546
Re: High Target SNR.
« Reply #11 on: December 17, 2018, 08:58:01 AM »

that is an error prone line.

It isnt fast path yet has accumulated dozens of SES.  Hard for me to comment much further then that tho.  As very limited info.

You can see from stats in my sig I am on fast path and have 0 SES.  So those are possibly related to your resyncs, you may be getting bursts of instability which causes the modem to drop out.

When you contact plusnet, dont go on about your speed, concentrate on the disconnections.  The former is a complaint they probably hear every day from many people and are trained to absorb it, the latter is a real problem that needs dealing with.  Exaggerate if you have to, tell them it drops out when watching netflix etc.
« Last Edit: December 17, 2018, 09:01:40 AM by Chrysalis »
Logged
Sky Fiber Pro - Billion 8800NL bridge & PFSense BOX running PFSense 2.4 - ECI Cab - LINE STATISTICS CLICK HERE

jelv

  • Helpful
  • Kitizen
  • *
  • Posts: 1234
Re: High Target SNR.
« Reply #12 on: December 17, 2018, 10:04:53 AM »

Yeah for some reason the GUI reports the attenuation value as the SNR value (I was checking the GUI first, this is the first time Iíve actually used the telnet stats in a while!).

If you are still using the HG612, the GUI looks perfectly OK to me.
Logged
Line rental: Pulse8, Broadband: AAISP Home::1 FTTC 80/20, Mobile: id Mobile

jelv

  • Helpful
  • Kitizen
  • *
  • Posts: 1234
Re: High Target SNR.
« Reply #13 on: December 17, 2018, 10:13:03 AM »

I hadn't done the quiet line test, so did one today and it reveals faint buzzing and popping noises.

You need to repeat the quiet line test using a corded phone plugged in to the test socket (without a filter and modem). If there is an issue that needs reporting as a voice line fault. If it is clear you need to gradually put things back together checking the line at each stage to identify what causes the popping.

If there are audible issues with the line it's pointless worrying about sync speed, target noise margin, error rates, resyncs etc - they are just the symptoms.
Logged
Line rental: Pulse8, Broadband: AAISP Home::1 FTTC 80/20, Mobile: id Mobile

xreyuk

  • Reg Member
  • ***
  • Posts: 124
Re: High Target SNR.
« Reply #14 on: December 17, 2018, 11:55:56 AM »

Attached is what I see when using the GUI, as you can see the values are in the wrong place. Software version is: V100R001C01B030SP08, and firmware version is A2pv6C038m.d24j. From what I understand this is the latest firmware?

Thanks, I'll repeat the quiet line test, as I did use a normal handheld phone, but didn't unplug the filter.

With regards to limited information, is there anything I can do to get better information for you guys? I did use to run DSLStats but stopped.
Logged
Pages: [1] 2 3