topic Re: New gateway - DLM reset in Full Fibre

New gateway - DLM reset

Justinian — Mon, 01 Nov 2021 11:21:54 GMT

Hello,

I've got a new Zyzel XMG-3927-B50 to replace the old VMG-8924 I had to change because of the security patches missing from it.

The new modem has dropped my sync speed from 72mbs to about 65mbs while having exactly the same stats as the old one. 2.8 db snr and 52 on INP. I cannot explain this drop since the SoC is about the same.

Would it be possible to perform a DLM reset on my in the hope the new GW will sync to the same speed as the previous 8924 ?

Need to mention that I've not used a filter on the 8924 and I am not using one on the 3927 either, I am not using this land-line for phone calls and there is no phone connected to it.

Thanks in advance.

Re: New gateway - DLM reset

Baldrick1 — Mon, 01 Nov 2021 12:37:14 GMT

@Justinian

Plusnet can only request a DLM reset if the line is banded, which would be reflected in a higher SNR. It sounds to me like the modem in your new Hub is inferior to the old one.

Re: New gateway - DLM reset

Justinian — Mon, 01 Nov 2021 12:44:09 GMT

It doesn't seem to be banded though something is very weird in the stats:

ZySH> xdslctl info --stats

xdslctl: ADSL driver and PHY status

Status: Showtime

Last Retrain Reason: 0

Last initialization procedure status: 0

Max: Upstream rate = 13468 Kbps, Downstream rate = 64423 Kbps

Bearer: 0, Upstream rate = 13464 Kbps, Downstream rate = 65426 Kbps

Bearer: 1, Upstream rate = 0 Kbps, Downstream rate = 0 Kbps

Link Power State: L0

Mode: VDSL2 Annex B

VDSL2 Profile: Profile 17a

TPS-TC: PTM Mode(0x0)

Trellis: U:ON /D:ON

Line Status: No Defect

Training Status: Showtime

Down Up

SNR (dB): 2.8 6.2

Attn(dB): 19.4 0.0

Pwr(dBm): 12.6 7.6

The sync speed is higher than the max speed.

Re: New gateway - DLM reset

RealAleMadrid — Mon, 01 Nov 2021 14:08:20 GMT

@Justinian The max rate is a calculated value not an actual speed and it can be either above or below the actual sync speed. On interleaved lines it tends to be way above the actual speed, on the other hand with G.Inp active allowing lower SNRM values as in your case it can be below the sync speed. My line has a max of 78.396 Mbps with a sync speed of 79.999 Mbps

I don't see your speed improving as you are already below the minimum 3 dB SNR margin.

Re: New gateway - DLM reset

Baldrick1 — Mon, 01 Nov 2021 14:25:08 GMT

@Justinian

Out of interest have you tried plugging directly in to the test socket located behind the master socket? This eliminates a connector pair in circuit. Also have you tried plugging in a filter to see if the voice filter also helps terminate the incoming line?

Beware too many disconnects, especially if you don't drop the DSL line first as you may trigger the DLM into slowing you down furher.