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Author Topic: Meritez GEA FTTC DLM Profile summarised since 2016  (Read 1475 times)

meritez

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Meritez GEA FTTC DLM Profile summarised since 2016
« on: June 20, 2019, 08:27:24 PM »

If anyone has any questions please let me know

My FTTC was installed on Go Live Date - 22/04/2016

My GEA Test at install showed:

Code: [Select]
Sync Status In Sync
Downstream Speed (MBPS) 80.0
Upstream Speed (MBPS) 20.0

Pretty much a perfect line, fast forward to December 2016, and I had dropped to a 40/10 connection as I did not need the speed:

Code: [Select]
Sync Status In Sync
Downstream Speed (MBPS) 40.0
Upstream Speed (MBPS) 10.0

Profile name Profile change time stamp
0.128M-40M Downstream, Retransmission Low - 0.128M-10M Upstream, Error Protection Off 2016-12-01T11:45:00

April 2017, I'm back on 80/20

Code: [Select]
Sync Status In Sync
Downstream Speed (MBPS) 79.9
Upstream Speed (MBPS) 20.0

Profile name Profile change time stamp
0.128M-80M Downstream, Retransmission Low - 0.128M-20M Upstream, Error Protection Off 2017-03-22T14:45:00

November 2017, I ditch my TP-Link W8970 flashed to W9980 running 150507 Firmware because I start testing out Broadcom chipsets, Billion 8800nl R2 and Zyxel VMG1312-B10A, HG612 etc:

Code: [Select]
Sync Status In Sync
Downstream Speed (MBPS) 40.0
Upstream Speed (MBPS) 10.0

Profile name Profile change time stamp
0.128M-74M Downstream, Retransmission High - 0.128M-20M Upstream, Error Protection Off 2017-10-25T09:30:00
0.128M-74M Downstream, Retransmission Low - 0.128M-20M Upstream, Error Protection Off 2017-11-01T06:30:00
0.128M-40M Downstream, Error Protection Off - 0.128M-10M Upstream, Error Protection Off 2017-11-07T01:30:00

Forward a year, as I have been busy, and I now have free time to check the line:

Code: [Select]
Sync Status In Sync
Downstream Speed (MBPS) 65.7
Upstream Speed (MBPS) 20.0

Profile name Profile change time stamp
0.128M-80M Downstream, Interleaving Low - 0.128M-20M Upstream, Error Protection Off 2018-10-19T13:15:00

Something is off, as surely I should be on 80/20 sync or near abouts:

Log a fault with the carrier, they advise there is a fault with the line, fix the fault but sync is still at the low end of my expected throughput.

5th June 2019, I replace the Zyxel VMG1312-B10A with a Netgear DM200, GEA Test from the 6th June shows:

Code: [Select]
Sync Status In Sync
Downstream Speed (MBPS) 62.1
Upstream Speed (MBPS) 20.0

It has been over 6 months, so I give up on my line ever improving, but on the 18th June at 01:45 in the morning I notice my line re-authenticates.

Requesting a GEA Test shows:

Code: [Select]
Profile name Profile change time stamp
0.128M-80M Downstream, Interleaving Low - 0.128M-20M Upstream, Error Protection Off 2019-06-06T10:00:00
0.128M-80M Downstream 5dB, Retransmission High - 0.128M-20M Upstream, Error Protection Off 2019-06-18T00:45:00

So where do I start:

My line has been on Retransmission Low for most of the 3 years, my original W8970 router from TP-Link was running a dsl driver that would never be updated or keep in line with Openreach's software updates.

https://xdarklight.github.io/lantiq-xdsl-firmware-info/ 5.7.4.3.0.6-5.7.1.8.0.1 if anyone is curious, which never got vectoring support, or other bug fixes.

swapping to Broadcom chipset based routers masked the issue for me, even though I'm on a Huawei Cabinet, DLM always deemed the line was working within specifications.

My Netgear DM200 is running 5.7.B.5.0.7-5.7.5.4.0.1 running on a custom compiled Openwrt 18.06.2 release https://github.com/a1comms/openwrt-netgear-dm200-bridge which silently bridges the dsl connection to another router.

I have no reason to change it at present, just thought people might like to see what DLM does trying to improve a line.
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kitz

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Re: Meritez GEA FTTC DLM Profile summarised since 2016
« Reply #1 on: June 21, 2019, 09:57:33 PM »

Like you 2 years ago I was easily syncing at the full 80Mbps (and had been since 2013).  Over time crosstalk has gradually eroded my sync speed. Crosstalk bit really bad when my immediate neighbour got FTTC for the first time last year.   I now usually sync at around 64Mbps. 

Code: [Select]
Sync Status In Sync
Downstream Speed (MBPS) 62.1

That is probably due to a DLM reset after the 'fixed fault'.  Interleaving is usually applied by default.

You are lucky that you are on a Huawei cab, as the DLM has realised your line is now stable.  The resync this morning has applied g.inp and reduced your target SNRM to 5dB, which should give you a wee bit more speed back.   Those of us stuck on ECI cabs don't even have that luxury :(
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flilot

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Re: Meritez GEA FTTC DLM Profile summarised since 2016
« Reply #2 on: June 21, 2019, 10:26:21 PM »

Those of us stuck on ECI cabs don't even have that luxury :(

Does DLM not reduce SNR after a while on very stable lines on ECI cabs then? I know G.INP doesn't get used on ECI but still assumed DLM would still reduce SNR to try and maximise throughput.
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burakkucat

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Re: Meritez GEA FTTC DLM Profile summarised since 2016
« Reply #3 on: June 21, 2019, 11:19:41 PM »

Does DLM not reduce SNR after a while on very stable lines on ECI cabs then?

No, it does not try.  :no:  :(
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j0hn

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Re: Meritez GEA FTTC DLM Profile summarised since 2016
« Reply #4 on: June 21, 2019, 11:45:37 PM »

So where do I start:

My line has been on Retransmission Low for most of the 3 years, my original W8970 router from TP-Link was running a dsl driver that would never be updated or keep in line with Openreach's software updates.

Too many gaps to say what was going on.

Quote
0.128M-74M Downstream, Retransmission High - 0.128M-20M Upstream, Error Protection Off   2017-10-25T09:30:00
0.128M-74M Downstream, Retransmission Low - 0.128M-20M Upstream, Error Protection Off   2017-11-01T06:30:00
0.128M-40M Downstream, Error Protection Off - 0.128M-10M Upstream, Error Protection Off   2017-11-07T01:30:00


What happened between 2017-11-01 and 2017-11-07?
I assume you downgraded to 40/10?
Or DLM totally whacked your line...

Then...

Quote
0.128M-80M Downstream, Interleaving Low - 0.128M-20M Upstream, Error Protection Off   2018-10-19T13:15:00

Did you upgrade to 80/20 again?

back to...

Quote
My line has been on Retransmission Low for most of the 3 years

on the 18th June at 01:45 in the morning I notice my line re-authenticates.

That was  DLM lowering the target SNRM margin from 6dB to 5dB.
It favours Retransmittion High on lower SNRM targets.

Capping your sync for up to a week usually makes DLM change to Retransmittion Low.
It might even drop the target SNRM to 4dB giving you another few Mb on the downstream.

If you wish to try this it's explained in this post.
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meritez

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Re: Meritez GEA FTTC DLM Profile summarised since 2016
« Reply #5 on: June 25, 2019, 01:32:12 PM »

Posting from mobile, got moved to a 4db profile on the 21st :)
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meritez

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Re: Meritez GEA FTTC DLM Profile summarised since 2016
« Reply #6 on: June 30, 2019, 07:37:09 PM »


Capping your sync for up to a week usually makes DLM change to Retransmittion Low.
It might even drop the target SNRM to 4dB giving you another few Mb on the downstream.

If you wish to try this it's explained in this post.

can I do that on a Lantiq VRX220 chipset?
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j0hn

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Re: Meritez GEA FTTC DLM Profile summarised since 2016
« Reply #7 on: June 30, 2019, 07:51:20 PM »

You can't cap the sync but you can increase the target SNRM which would have the same effect.
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