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[staveley]

Hi Folks,
I'd really appreciate any advice/comments/pointers re my semi-rural FTTC line which is suffering from random disconnects, causing reduced download speeds.
Connection is Zen ISP>Huawei Cab>Zyxel VMG3925-B10B(Bridge)>Netgear R7800(OpenWRT)
Timeline is:
Oct'19 - Stable line with download speeds of 45-50Mbps & SNRM c.6-8dB.
Nov'19 - No service fault on voice line. Master socket replaced & some old extension wiring disconnected as OR engineer diagnosed short circuit
Dec'19-Apr'20 - Multiple line drops causing SNRM increase to 18dB, speed down to 30-35Mbps
Apr'20 - Battery contact fault detected, repaired by moving to new pair. OR engineer commented that external routing of line was "challenging"
May'20 - Multiple linedrops still occurring, SNRM 20-22dB, speed 30Mbps
Today (20/05/20) - 3 linedrops overnight with SNRM dropping to zero. This morning SNRM has stabilized at 3dB, speed 36Mbps

I'm hoping the DLM has finally kicked in but I'm concerned there's now no overhead for any further noise problems.
Current stats are:
Stats recorded 20 May 2020 11:55:57

DSLAM type / SW version:   BDCM:0xc01c (192.28) / v0xc01c
Modem/router firmware:     AnnexA version - A2pv6F039x6.d26u
DSL mode:                  VDSL2 Profile 17a
Status:                    Showtime
Uptime:                     7 hours 50 min 40 sec
Resyncs:                   6 (since 13 May 2020 17:31:54)
         
            Downstream   Upstream
Line attenuation (dB):     26.0      0.0
Signal attenuation (dB):   Not monitored      
Connection speed (kbps):   35912      7714
SNR margin (dB):           3.1      4.9
Power (dBm):               12.8      0.2
Interleave depth:          4      1
INP:                       54.00      0
G.INP:                     Enabled      Not enabled
Vectoring status:          1 (VECT_FULL)      

RSCorr/RS (%):             3.1864      0.0000
RSUnCorr/RS (%):           0.0000      0.0000
ES/hour:                   253      11.3


I've tried the following 'fixes':
- all network equipment fed from filtered UPS supply
- tried 3 different modems (Zyxel 1312/8925/3925)
- power recycled all equipment
- WAN connection hardwired directly to 5C master socket using CAT5e
- checked bellwire is not connected
- quiet line test run, some low-level crackling noise audible
- REIN checked at 612MHz, nothing found

Is there anything else in the DSLstats that would give a clue as to what is happening?

[mofa2020]

Welcome to Kitz forum

so, you are on Huawei cabinet and the download side is somehow messed up although Interleaving, G.INP and Vectoring all are enabled which should get more juice of the line and keep service more reliable and faster.

I believe the fault is not on your side cause on Nov'19 I think the issue is fixed once and for all unless you did change something inside house which may cause a fault again.

Did the line work normally from Nov'19-Dec'18?

As of Dec'19-Apr'20 did any try to fix the line happen? do you think a storm or bad weather triggered the service problem? also do you know ~ how far the cabinet is? on Apr'20 for the new pair and the challenging routing do you have phone line poles in the area or manholes from cabinet cause I believe that the old problem happened again on May'20 and a little bit worse..

20/5/2020 DLM finally found the line condition is suitable for a 3dB SNRM which is great but what on earth is going on 

Also please stop changing the modems, they are all Zyxel, awesome in performance and if one of them shows instability or drop in SNRM/speed probably it is not the modem and the same thing would happen with the other ones but DLM would probably be peed off more than it is already do.

Any update from 3dB sync.

[staveley]

@mofa2020
Thanks for your input. To answer your questions:

I believe the fault is not on your side cause on Nov'19 I think the issue is fixed once and for all unless you did change something inside house which may cause a fault again.

No changes internally

Did the line work normally from Nov'19-Dec'18?

As I recall, problem started after the Nov'19 repair. Certainly had issues from December onwards.

As of Dec'19-Apr'20 did any try to fix the line happen? do you think a storm or bad weather triggered the service problem? also do you know ~ how far the cabinet is? on Apr'20 for the new pair and the challenging routing do you have phone line poles in the area or manholes from cabinet cause I believe that the old problem happened again on May'20 and a little bit worse..

No fixes between Dec-Apr. No storms. Cabinet is approx 1.5km away. Supply is via poles.

Any update from 3dB sync.

There was a further linedrop overnight 20th-21st. SNRM started at 3dB then jumped to 7. This morning (Thursday) it jumped from 7 to 14 to 19.5 within one hour. Now (1930 BST) it has started to reduce, from 19.5 to 18.

[mofa2020]

I would suggest posting SNRM, SNRM per Band, and Bits from DSLstats, may show more useful
record of information.

[staveley]

Sorry for delay in responding, been running some more tests .......

No linedrops overnight Fri/Sat with SNRM stabilized at 18-20 & speed c.30Mb/s.


I raised the issue with ISP who wanted all the usual actions, e.g. reboot, check cables, etc, etc.
Before passing to Openreach, they asked me to try using the NTE5C test socket.
I replaced the existing Cat5e hardwired connection with an old RJ11 shielded modem cable and, wow, SNRM 6dB, speed 56Mb/s.


Connection has been rock solid over last 24 hrs.
So now I will investigate whether it's the Cat5e connection or something on the internal phone line that's the culprit.

Thanks for your assistance.

[mofa2020]

Sorry for delay in responding, been running some more tests .......

No linedrops overnight Fri/Sat with SNRM stabilized at 18-20 & speed c.30Mb/s.


I raised the issue with ISP who wanted all the usual actions, e.g. reboot, check cables, etc, etc.
Before passing to Openreach, they asked me to try using the NTE5C test socket.
I replaced the existing Cat5e hardwired connection with an old RJ11 shielded modem cable and, wow, SNRM 6dB, speed 56Mb/s.


Connection has been rock solid over last 24 hrs.
So now I will investigate whether it's the Cat5e connection or something on the internal phone line that's the culprit.

Thanks for your assistance.

You are welcome and this is great to hear  yes I tried a Cat5 but as happened to you service was not stable at all, I guess it is a matter of time before the DLM kick in and lower SNRM to 3dB which would give you more sync. speed..

My advice is to delay any tests on the line you intend to try, keeping things stable and untouched is actually a test for everything active on the phone line (either voice or internet).