Getting a 3db SNR Margin on NowTV Broadband?

So we've just moved from virgin media cable to NowTV FTTC (yeah, big downgrade, it's just as a cost cutting exercise).

We have underground fed Openreach line and router connected directly to NTE5, no extensions.

Getting a very healthy 71.8 down with 6.3dB margin and 20.0 up with 11.8dB margin.

Line is solid as a rock, it's been connected 9 days straight with no dropouts. Noise margin doesn't fluctuate throughout the night or day by even 0.1dB.

So, was wondering what can be done to get a 3dB target margin? Edge us closer to that full 80/20?

Edited by deleted (Sun 27-Feb-22 21:38:17)

Nothing. Just wait. Leave the modem/hub connected and running continually without any switching off or rebooting.

If you are connected to an ECI cabinet then you are stuck on a fixed 6dB target. It's only the Huawei cabinets that have lower SNRM targets.

If you are on a Huawei cabinet and have the right kind of Broadcom/Lantiq chipset modem then you can cap your sync rate which often nudges the DLM in to trying a lower target but without such a modem there nothing you can do but wait and hope.
Not all Huawei lines will go below 6dB either.

Interesting topic. I am on a Huawei cabinet and I am on 9.7db which is as low as it has been in 5 years. Speeds are 70 to 74 down and 16 to 17 up. Would I reach the magic 80 download if db was lower? I am with BT and yes very happy with service.

Could you post your full stats? The line should be on 6dB and should only really be higher than that if either you are synced at the product cap or the line is capped (banded) by the DLM.

80Mb is the highest sync possible but download speeds won't reach that.

If those are your download speeds rather than your line stats, you ARE synced at maximum speed.

There's no guarantees that lowering the noise margin to 3dB will achieve max sync speeds.

I have been with TalkTalk FTTC for just over 2 years now. Originally I was connecting 80/20 with a 6dB noise margin and then it dropped to 3dB after a year and a half.

In recent months I am no longer syncing at 80/20. Now my download speed has dropped but my noise margin is still the same.

Actual Rate [Kbps] 75735 19999
Maximum Rate [Kbps] 74393 19999
Noise Margin [dB] 2.80 6.30

75.7Mbps is the best I have been on for the past 5 months or so with a noise margins of under 3dB. All this is due to an effect of crosstalk. Too many customers have joined FTTC and this has dropped my connection speeds.

I always feared this was going to happen eventually. Even though I'm out of contract now, I haven't changed supplier yet because CommunityFibre FTTP were supposed to go live soon, but they haven't yet.

I'm waiting for FTTP to come to my building, which shows as "Coming Soon". As soon as this happens, I'll migrate. Maybe one day if more people get access to FTTP then that might relieve the pressure on the FTTC crosstalk impact for their cabinet. But then again by then it will be kinda futile as FTTC will become obsolete anyway.

Most FTTC lines technical maximum speed is 76Mbps/18Mbps, Fair as i know, AAISP and Vivaciti do the full 80/20 profiles.

https://www.unitconverters.net/data-transfer/kbps-to...
76Mbps, your looking at 77824kbps if you count 1Mb as 1024kbps
18Mbps, your looking at 18432kbps if you count 1Mb as 1024kbps

Edited by francisuk25 (Tue 01-Mar-22 10:35:50)

Post deleted by merrymouse

Sounds spot on for BT

The HG612 displays many incorrect stats. Some are in the wrong field, some are duplicates from other fields, other stats are just plain wrong.

The sync speed shows you at the full 80/20.

I think the SNRM/noise margin shown may also be incorrect.

You need to connect via Telnet or ssh and run some commands to get accurate stats.

Thanks for reply. You will be able to read more into these stats more than I will.
https://i.postimg.cc/qvXKwnBX/stats.jpg
https://i.postimg.cc/Dz6qvGty/speed-test.jpg

In reply to a post by francisuk25:

76Mbps, your looking at 77824kbps if you count 1Mb as 1024kbps
18Mbps, your looking at 18432kbps if you count 1Mb as 1024kbps

This is wrong. Data comms *never* use power-of-two units. This has been true from the days of ISDN voice channels (8,000 samples per second, 8 bits per sample = exactly 64,000 bits per second). Gigabit ethernet is 1,000,000,000 bits per second.

If your DSL modem reports 79,999kbps then it's 79,999,000 bits per second.

EDIT: the page you linked to gives the correct definitions of kilobits per second and megabits per second - but then a completely spurious conversion table and spurious "How to Convert" section, which ignore those definitions.

Edited by candlerb (Tue 01-Mar-22 11:02:06)

In reply to a post by francisuk25:

Most FTTC lines technical maximum speed is 76Mbps/18Mbps, Fair as i know, AAISP and Vivaciti do the full 80/20 profiles.

AAISP don't even do their own profiling. It's done by their wholesaler.

All providers sync at the full 80Mb.
AAISP use the BT Wholesale IP profile on their BT Wholesale lines and they use Talktalks profile system on their Talktalk lines. What they show in their control panel is what's passed on to them.
You don't get any more throughput with AAISP than you do with any other ISP.

It's all down to the chipset of the modem and the DLM profile in use.
Different DLM profiles come with different throughput levels.

Fastpath will give an IP Profile 96.79% of the sync speed.
Retx Low gives an IP Profile 96.69% of the sync speed.
Retx High gives an IP Profile between 91-92% of sync speed.

https://www.unitconverters.net/data-transfer/kbps-to...
76Mbps, your looking at 77824kbps if you count 1Mb as 1024kbps
18Mbps, your looking at 18432kbps if you count 1Mb as 1024kbps

That's confusing things for no reason at all.

In networking, data, throughput etc 1Mb is almost always 1000 Kb

A modem synced at 80Mbps is synced at 80000Kbps.
A speed test of 76Mbps is 76000Kbps

Edited by j0hn83 (Tue 01-Mar-22 11:09:34)