No point complaining to Talktalk.
DLM applies interleaving to new connections automatically.
This takes about 10% of your sync speed.

Give it a week or 2 and G.INP will return and you will be at 79,999Kbps again.

Edited by j0hn83 (Sun 24-Jun-18 21:36:15)

In reply to a post by j0hn83:

DLM applies interleaving to new connections automatically.
This takes about 10% of your sync speed.

Internet myth/misinformation I'm afraid John.

2.2 User Network Interface - General

2.2.1 Dynamic Line Management

Dynamic Line Management (DLM) is employed in GEA-FTTC. DLM constantly manages lines to maintain a target link quality (speed and stability). It does this for as long as the product exists.

At provision, the line is put on �wide open� VDSL2 line profiles allowing the upstream and downstream line speeds to run at the upper limit of the product option selected.

On the first day of operation, DLM will intervene if severe instability is detected. Otherwise, DLM will wait until the day after provision before deciding if it must intervene, provided that the line has been trained up for at least 15 minutes during the preceding day.

BT (Openreach) SIN 498.

That said, TalkTalk do select the stability option that Openreach offer. Exactly what effect that has on VDSL2 as opposed to ADSL2+ I don't know off hand. The SIN certainly does not say it adds Interleaving automatically.

Edited by RobertoS (Sun 24-Jun-18 22:09:49)

Absolutely not.
ECI cabinets will go wide open
Huawei cabinets have interleaving on the downstream by default.

May I point you to the words of OpenReachs Ian Lawrence discussing the Huawei estate

https://kitz.co.uk/adsl/ginp-retransmission.htm

in particular

Downstream

Initially, low interleaving is enabled by default on all retransmission lines. Once DLM has positively identified that the modem supports retransmission then retransmission is enabled. This happens after a few days. If the low level of retransmission is not good enough to correct all errors then the high level is selected by DLM. If the line remains unstable and cannot be adequately managed by DLM with retransmission profile then Interleaving is applied as normal.

Every time I've switched ISP I've had interleaving applied by default (Huawei cabinet).

Edited by j0hn83 (Sun 24-Jun-18 22:10:54)

What John83 said

I think that Q & A is a bit confusing, and has confused you.

It is clearly specifically discussing what happened when G.INP was originally introduced and messed up, and Openreach were sorting it out. The key words being "retransmission lines". That means lines that have G.INP enabled.

The Q & A is dated August 2015. The SIN link I gave you is dated April 2018. The implementation of G.INP has changed considerably since then, (Edit: August 2015) as have many other behaviours of DLM when making line profile (nothing to do with IP Profile) adjustments.

In particular, G.INP has never been applied on initial connection. That Q & A never did say what you posted.

Note that, independent of all that, on Huawei cabinets at least, G.INP is only activated in order to remove the high interleaving and "delay" levels that DLM does impose if it finds that the "ADSLx Fast Path equivalent" interleaving setting is needed and it has set it. As you say, this standard form of interleaving does cause a loss of about 10Mbps sync, and at least 8ms "delay".

After a few days DLM often decides to activate G.INP instead, and when it does the sync returns to normal. Interleaving is still applied when G.INP is active, typically at a level of 8 rather than the hundreds and often thousands of standard interleaving. At the same time as activating G.INP, the "delay" parameter is set to zero instead of 8ms or higher. (On Bearer 0 which is what we care about).

See my stats below. Bearer 0 is the normal one. Bearer 1 is used by G.INP and is not present when it is not active. Bearer 1 syncs at 200bps so because of rounding appears as 0kbps.

xdslctl info --show
xdslctl: ADSL driver and PHY status
Status: Showtime
Last Retrain Reason: 0
Last initialization procedure status: 0
Max: Upstream rate = 12795 Kbps, Downstream rate = 71751 Kbps
Bearer: 0, Upstream rate = 12769 Kbps, Downstream rate = 71307 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 6.0
Attn(dB): 19.4 0.0
Pwr(dBm): 13.7 7.4

VDSL2 framing
Bearer 0
MSGc: -6 26
B: 243 237
M: 1 1
T: 0 53
R: 10 16
S: 0.1090 0.5926
L: 18649 3429
D: 8 1
I: 254 127
N: 254 254
Q: 8 0
V: 0 0
RxQueue: 80 0
TxQueue: 20 0
G.INP Framing: 18 0
G.INP lookback: 20 0
RRC bits: 0 24
Bearer 1
MSGc: 154 -6
B: 0 0
M: 2 0
T: 2 0
R: 16 0
S: 6.4000 0.0000
L: 40 0
D: 3 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 196466515
OHFErr: 6825 63
RS: 572882152 1822407022
RSCorr: 1655234116 718
RSUnCorr: 0 0
Bearer 1
OHF: 96033991 0
OHFErr: 1327 0
RS: 960339299 0
RSCorr: 6293804 0
RSUnCorr: 4921 0

Retransmit Counters
rtx_tx: 11655481 0
rtx_c: 11017661 0
rtx_uc: 149773 0

G.INP Counters
LEFTRS: 1060 0
minEFTR: 71286 0
errFreeBits: 1674808635 0

Bearer 0
HEC: 0 0
OCD: 0 0
LCD: 0 0
Total Cells: 721176533 0
Data Cells: 235213954 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: 545 61
SES: 131 0
UAS: 27 27
AS: 1542570

Bearer 0
INP: 51.00 0.00
INPRein: 1.00 0.00
delay: 0 0
PER: 0.00 7.88
OR: 0.01 32.47
AgR: 71380.32 12801.99

Bearer 1
INP: 4.50 0.00
INPRein: 4.50 0.00
delay: 3 0
PER: 16.06 0.01
OR: 79.68 0.01
AgR: 79.68 0.01

Bitswap: 1174986/1248525 13497/13569

Edited by RobertoS (Sun 24-Jun-18 22:52:39)

In reply to a post by MrSaffron:

What John83 said

????

...

lines fed by a Huawei cabinet start interleaved.

Read the thousands of posts from users that confirm this.

In reply to a post by j0hn83:

Read the thousands of posts from users that confirm this.

Where?

Bear in mind we are talking about initial connection. Not connection after a migration.

On migration between ISPs on the same underlying provider, basically BT Wholesale, TalkTalk Business and Vodafone, DLM is not reset. So if a line is on interleaved before migration it will stay so.

However, if changing platform, such as moving from BT Wholesale to Sky/TalkTalk/Vodafone or back, then DLM is reset to the conditions specified in SIN 498. Subject to the stability option chosen by the ISP.

Edited by RobertoS (Sun 24-Jun-18 22:57:45)

Chasing the service you pay for is admirable practice!

DLM resets which happen when moving between providers see G.INP turned off, and comes back some days later

So has the move of the original poster been between platforms.

On the DLM I am sure we can debate the system based on SIN for many years, which might not turn out to be exactly how it plays out in practice