Big speed drop after modem upgrade to Zyxel 8924

I am wondering if anyone can help me with an issue since upgrading my modem from a Hg612 to a Zyxel 8924.

I read that the Zyxel could get a better sync speed than the HG612 so I purchased one and set it up. I was previously getting around 11.5mb sync speed on the HG612. As soon as i connected the Zyxel I was getting 12.2 sync all well and good. I then went on holiday for 10 days. After getting back I checked my line stats, much to my dismay my speed had dropped to 8.8mb sync speed. I tried the HG612 again and it too was connecting at around the same now. My stats are as follows:

adsl info --stats
adsl: ADSL driver and PHY status
Status: Showtime
Last Retrain Reason: 0
Last initialization procedure status: 0
Max: Upstream rate = 1105 Kbps, Downstream rate = 13120 Kbps
Bearer: 0, Upstream rate = 1105 Kbps, Downstream rate = 8800 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): 10.8 6.3
Attn(dB): 35.4 0.0
Pwr(dBm): 10.1 10.5

VDSL2 framing
Bearer 0
MSGc: -6 26
B: 49 31
M: 1 1
T: 0 50
R: 6 0
S: 0.0000 0.9046
L: 2537 283
D: 4 1
I: 56 32
N: 56 32
Q: 4 0
V: 3 0
RxQueue: 100 0
TxQueue: 25 0
G.INP Framing: 18 0
G.INP lookback: 25 0
RRC bits: 0 24
Bearer 1
MSGc: 90 -6
B: 0 0
M: 2 0
T: 2 0
R: 16 0
S: 10.6667 0.0000
L: 24 0
D: 1 0
I: 32 0
N: 32 0
Q: 0 0
V: 0 0
RxQueue: 0 0
TxQueue: 0 0
G.INP Framing: 0 0
G.INP lookback: 0 0
RRC bits: 0 0

Counters
Bearer 0
OHF: 0 14427
OHFErr: 0 0
RS: 3655316 721034
RSCorr: 3 0
RSUnCorr: 0 0
Bearer 1
OHF: 10147 0
OHFErr: 0 0
RS: 60514 0
RSCorr: 0 0
RSUnCorr: 0 0

Retransmit Counters
rtx_tx: 110983480 0
rtx_c: 13 0
rtx_uc: 0 0

G.INP Counters
LEFTRS: 0 0
minEFTR: 8800 0
errFreeBits: 82410 0

Bearer 0
HEC: 0 0
OCD: 0 0
LCD: 0 0
Total Cells: 2758383 0
Data Cells: 373 0
Drop Cells: 0
Bit Errors: 0 0

Bearer 1
HEC: 0 0
OCD: 0 0
LCD: 0 0
Total Cells: 0 0
Data Cells: 0 0
Drop Cells: 0
Bit Errors: 0 0

ES: 0 0
SES: 0 0
UAS: 57 57
AS: 163

Bearer 0
INP: 52.00 0.00
INPRein: 1.00 0.00
delay: 0 0
PER: 0.00 11.35
OR: 0.01 22.55
AgR: 9025.45 1127.59

Bearer 1
INP: 2.50 0.00
INPRein: 2.50 0.00
delay: 0 0
PER: 16.06 0.01
OR: 47.81 0.01
AgR: 47.81 0.01

Bitswap: 3/3 0/0

Total time = 7 min 27 sec
FEC: 9 0
CRC: 0 0
ES: 0 0
SES: 0 0
UAS: 57 57
LOS: 0 0
LOF: 0 0
LOM: 0 0
Latest 15 minutes time = 7 min 27 sec
FEC: 9 0
CRC: 0 0
ES: 0 0
SES: 0 0
UAS: 57 57
LOS: 0 0
LOF: 0 0
LOM: 0 0
Previous 15 minutes time = 0 sec
FEC: 0 0
CRC: 0 0
ES: 0 0
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
LOM: 0 0
Latest 1 day time = 7 min 27 sec
FEC: 9 0
CRC: 0 0
ES: 0 0
SES: 0 0
UAS: 57 57
LOS: 0 0
LOF: 0 0
LOM: 0 0
Previous 1 day time = 0 sec
FEC: 0 0
CRC: 0 0
ES: 0 0
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
LOM: 0 0
Since Link time = 2 min 43 sec
FEC: 3 0
CRC: 0 0
ES: 0 0
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
LOM: 0 0
NTR: mipsCntAtNtr=0 ncoCntAtNtr=0
>

As can be seen there is plenty of headroom in the downstream SNR -previously it was at around 6ish and now it has jumped up to 11. How can I get back my missing 3.5mb? What has happened!!

Looks like I am now banded to 8800 connection speed

It always connects at exactly that. Is there any way to get rid of the banding?

Time and banding may eventually remove itself.

High chance that storms or some other rf noise events caused errors while you were away and DLM intervened to ensure as few errors as possible.

It was definitely switching to the Zyxel that caused it, before that it was rock solid. I think I must have triggered DLM when I installed the new router as I kept rebooting it trying to configure it so I could view live stats through my normal network.

I read on here that once you are banded it is almost certain it will stay that way - not sure how true that is?

If in a couple of weeks if it doesn't go back up I will just go back to normal adsl as I was getting 11mb through that previously.

I don't suppose there is any way to get sky to request a dlm reset?

DLM resets tend to only happen after an engineer visit, I've seen banding relent in stages over the course of a few months, so it does happen.

Is the Zyxel a stand alone Router or Modem or is it a combined Modem/Router.
If it is just a Router it should not trigger any DLM faults by resetting it etc as I turn off my Router every night without problems.
But the Modem OR, or any brand if turned off can trigger the DLM in the cab, did you turn off the Modem when you went away,?
If so the DLM would think it was a power cut and react.

It has a built in VDSL2 modem and router with dual band 802.11ac and is not a cheap beast at £165 on Amazon

Thanks Mr Saffon, A combined Modem/Router is ok [sounds cool].
But if the OP turned it off when away the DLM would react and introduce the banding.?
With a separate router the Modem must still be online.?

I was using the Zyxel in bridged mode as just a modem - I bought it used so not sure if it's faulty or perhaps the phone cable had issues. Prior to that the dsl connection was up for 2 months without dropping using a HG612

Guess I will have to wait and see, or move back to adsl. 3mb sync doesn't seem like much but it's literally 30% of my bandwidth

Edited by deleted (Fri 12-Aug-16 20:45:07)

No and no.

Turning kit off occasionally should have no effect on the DLM.

In fact turning it off and disconnecting from both the line and the mains is advisable if going away on holiday for a while. I wouldn't bother over a weekend as long as thunderstorms weren't expected, and I ignore thunderstorms even when they occur while I'm here, but lightning in the vicinity can put very nasty stuff down the line. Strong enough to fry the electronics even when turned off, if still physically connected.

Even if lightning doesn't cause any damage, the electro-magnetic noise on the line over the length of time thunder can be around during a storm could send the DLM into a panic.

Mains electricity can be dodgy on resumption from a power cut.