VDSL line stats

Just renewed my broadband contract with Vodafone, and they've treated it as a new connection and it seems reset the DLM on my line, although still using the same Vodafone supplied router. For several years previous it had been settled around 16mb dl, 1.6mb ul, with an interleaving depth of around 350. Since the DLM reset, interleaving has been removed (so far anyway).

Unfortunately, my line is 1950m from the serving cabinet (800 as the crow flies). So my speeds are obviously going to be hampered by the distance. But I'd like to check that it's performing as best it can as there's no prospect of FTTP any time soon.

This is what my vodafone router was reporting this morning, 6 days since DLM reset:

https://thumbsnap.com/pgqBHmfY

And since I'm now on SOGEA service I no longer need a filter, so in attempt to eek out every little bit of speed I've got a short phone to rj11 cable and gone straight from the test socket into the router, bypassing the filtered faceplate.

Now I'm getting these line stats:

https://thumbsnap.com/GydgQMeg

That's certainly the fastest dl speed I've ever had, and it appears that the SNR margin has increased a bit too. The max rate has also increased a bit (think that's calculated based on the current rate and the SNR margin/headroom?)

The vodafone router seems to be aiming for at least a 6db noise margin. Is it possible the DLM will allow the line will sync up a bit faster in time, to get the highest speed it can while maintaining 6db? The BT availability checker is estimating VDSL Range A high as 20mb, does the DLM use that as ceiling for sync rate or is it the reverse - the speed estimate based off existing line stats?

The DLM knows nothing about the BT checker figures, the limited line stats you've shown do not show if G.Inp ( aka retx) is enabled. If it is DLM can reduce the SNRM value down to 3dB. That is the only way it can increase your speed. Some FTTC cabinets using ECI dslam equipment do not support G.Inp so you may be stuck with the best you can get.

The codelook website will show what type of dslam is installed in your FTTC cabinet.

In reply to a post by Realalemadrid:

The DLM knows nothing about the BT checker figures, the limited line stats you've shown do not show if G.Inp ( aka retx) is enabled. If it is DLM can reduce the SNRM value down to 3dB. That is the only way it can increase your speed. Some FTTC cabinets using ECI dslam equipment do not support G.Inp so you may be stuck with the best you can get.

The codelook website will show what type of dslam is installed in your FTTC cabinet.

Vodafone's router doesn't show whether GInp is on, but yes it's an ECI cabinet serving and I don't think it has GInp enabled at that end anyway (It didn't get enabled when I connected my old Draytek router which is GInp capable, but only annex A, so I'm not sure if that affects it).

In reply to a post by mbdcs2:

but only annex A, so I'm not sure if that affects it).

Ignore the Annex that's specified. It can't be changed. You can't connect with the wrong Annex. Some routers simply report different Annex's.

Annex simply means part of a document/standard.

The UK uses physical infrastructure Annex A (PSTN/POTS) while much of Europe uses physical infrastructure Annex B (ISDN).

Then there's the Openreach DSLAM's which use an Annex B Bandplan Profile 17a from ITU-T G.993.2.

Lantiq chipset routers (Drayteks and Fritzboxes) report the connection as Annex A. They are reporting the hardware Annex.
Broadcom chipset routers report the connection as Annex B. They are reporting the bandplan.

Both are connected the exact same (infrastructure annex A with an Annex B bandplan) but just report different things.

Thanks.

Issue with the Draytek is that it's only syncing at about 0.75mb ul, whereas the vodafone router syncs at about 1.75mb ul. Though that might have been down to the Draytek being too old to understand a newer bandlplan annex, but must be some other reason for it?