How much will DLM likely change my connection?

I'm very late to the DSL party having always had Virgin Media cable in places where I've lived so never really got hands on anything DSL until recently. Now though I have a VDSL backup line through Vodafone. I'm currently within the 10 day period, so DLM will be monitoring and adjusting my line characteristics.

I'm using a DrayTek Vigor 130 as my modem which has been powered on since the line went active, other than a couple of reboots to get it setup and passing the VDSL signal to my router at the beginning, it's been constantly on.

My sync speeds started at:

Down Stream : 55000Kbps / Up Stream : 20000Kbps

After a couple of days I'm now syncing at:

Down Stream : 64156Kbps / Up Stream : 20000Kbps

Which has stayed like this for a few days. The SNR on both downstream and upstream has hovered between 5db and 6db (currently this).

Is the downwtream likely to increase anymore? Theoretically the max is 80 Mbps in my area according to BT wholesale checker, although Vodafone quote on average 63 Mbps, which I'm now above, although given I'm on day 4/5 of DLM, I'm aware the line characteristics could still be being modified.

The DS Attainable Rate seems to be not much more than what I'm syncing at, I believe it has been pretty much this from the start, can this change at all or is it generally fixed?

This is the DSL stats output from the DrayTek.

> vdsl status

---------------------- ATU-R Info (hw: annex A, f/w: annex A/B/C) -----------
Running Mode : 17A State : SHOWTIME
DS Actual Rate : 64156000 bps US Actual Rate : 20000000 bps
DS Attainable Rate : 65151016 bps US Attainable Rate : 23977772 bps
DS Path Mode : Fast US Path Mode : Fast
DS Interleave Depth : 1 US Interleave Depth : 1
NE Current Attenuation : 13 dB Cur SNR Margin : 6 dB
DS actual PSD : 1. 5 dB US actual PSD : 1. 7 dB
NE CRC Count : 151 FE CRC Count : 109
NE ES Count : 129 FE ES Count : 65
Xdsl Reset Times : 0 Xdsl Link Times : 2
ITU Version[0] : fe004452 ITU Version[1] : 41590000
VDSL Firmware Version : 05-07-06-0D-01-07 [with Vectoring support]
Power Management Mode : DSL_G997_PMS_L0
Test Mode : DISABLE
-------------------------------- ATU-C Info ---------------------------------
Far Current Attenuation : 11 dB Far SNR Margin : 8 dB
CO ITU Version[0] : b5004946 CO ITU Version[1] : 544eb206
DSLAM CHIPSET VENDOR : < IFTN >

Actually there is no 10 day training period, DLM is acting continuously and usually the sync speed adjusts to the best possible levels after a couple of days which means you are probably not going to get any further increase in download speed. Speeds can increase later under some conditions which probably do not apply to your line. (see below)

The main reason that no further changes will occur is "DSLAM CHIPSET VENDOR : < IFTN >" which indicates an ECI Dslam in the fibre cabinet. You are unlikely to get G.Inp or retransmission which is an improved error correction method and can increase your speed, although there have recently been some trials on a small number of ECI cabs.

If you were on a Huawei cab you would get G.Inp followed by reduced SNRM values in stages down to 3dB which would be likely to give you full 80Mbps sync. Unfortunately there is no firm evidence that ECI cabs on the G.Inp trial reduce the SNRM. Openreach have made various attempts to get G.inp working on ECI cabs but have not yet managed it.

The only other possibility is that a modem using a Broadcom chipset may give you a better sync speed, there is no way of knowing without actually trying. I use the Openreach Huawei HG612 3B which although it doesn't have the latest chipset works well on my line.

In reply to a post by jamesmacwhite:

I'm currently within the 10 day period, so DLM will be monitoring and adjusting my line characteristics.

It is very sad how this misinformation perpetuates. That applied on some ADSL services, but with FTTC (VDSL) there is no 10 day, DLM is monitoring all the time, forever.

In reply to a post by Realalemadrid:

Actually there is no 10 day training period, DLM is acting continuously and usually the sync speed adjusts to the best possible levels after a couple of days which means you are probably not going to get any further increase in download speed. Speeds can increase later under some conditions which probably do not apply to your line. (see below)

The main reason that no further changes will occur is "DSLAM CHIPSET VENDOR : < IFTN >" which indicates an ECI Dslam in the fibre cabinet. You are unlikely to get G.Inp or retransmission which is an improved error correction method and can increase your speed, although there have recently been some trials on a small number of ECI cabs.

If you were on a Huawei cab you would get G.Inp followed by reduced SNRM values in stages down to 3dB which would be likely to give you full 80Mbps sync. Unfortunately there is no firm evidence that ECI cabs on the G.Inp trial reduce the SNRM. Openreach have made various attempts to get G.inp working on ECI cabs but have not yet managed it.

The only other possibility is that a modem using a Broadcom chipset may give you a better sync speed, there is no way of knowing without actually trying. I use the Openreach Huawei HG612 3B which although it doesn't have the latest chipset works well on my line.

Thank you for the information and clarifying DLM in the case of FTTC/VDSL. Interestingly I read about the whole ECI vs Huawei. Apparently there is an alternative firmware build for the DrayTek Vigor 130 which apparently works better with one or the other type of DSLAMs (can't remember which), but I don't know if it is worth messing around with that to be honest.

Edit: This is where I found such info: https://uktechhub.com/forums/topic/draytek-vigor-130... but it is just a forum topic, not necessarily conclusive or authoritative.

Looks like 64 Mbps is going to be about my limit then without further experiments. It's not too bad, it is a backup line after all.

Edited by jamesmacwhite (Tue 22-Sep-20 11:37:32)

In reply to a post by jchamier:

It is very sad how this misinformation perpetuates. That applied on some ADSL services, but with FTTC (VDSL) there is no 10 day, DLM is monitoring all the time, forever.

Thank for you pointing this out. I wasn't sure about this one, because of the different information I read about but thank you for clarifying. One less person that will perpetuate such misinformation now at least!

Whilst it isn't true that it runs for 10 days only it is true that most ISPs will not do anything about slow speeds until the DLM has had a chance to do its thing and make adjustments - they tend to do this as a 10 day "settling in" period. As you have seen yours has increased in speed from the original connection and so there is some merit in allowing things time to settle down before accepting "my broadband is too slow" calls.

I ended up testing the alternative firmware build for the DrayTek 130, it synced at a slightly higher downstream of a whopping 1 Mbps more, so I don't think there's a lot in it in my case.

Edited by jamesmacwhite (Thu 24-Sep-20 18:09:56)

In reply to a post by ian72:

Whilst it isn't true that it runs for 10 days only it is true that most ISPs will not do anything about slow speeds until the DLM has had a chance to do its thing and make adjustments - they tend to do this as a 10 day "settling in" period. As you have seen yours has increased in speed from the original connection and so there is some merit in allowing things time to settle down before accepting "my broadband is too slow" calls.

That makes sense. Vodafone won't be getting such calls from me, as it's not exactly for speed, having a backup line with a static IP is fine with me, it's VDSL at the end of the day!