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[mls2992a]

Had BT Infinity installed today and it came with HH6. Swapped it with a HG612 and started seeing packet loss.

Looking at DSL stats, seeing a lot of CRC errors and some ES errors.

xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason:   0
Last initialization procedure status:   0
Max:   Upstream rate = 32130 Kbps, Downstream rate = 80228 Kbps
Bearer:   0, Upstream rate = 19999 Kbps, Downstream rate = 77727 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):    6.8       15.4
Attn(dB):    12.7       0.0
Pwr(dBm):    12.7       1.0
         VDSL2 framing
         Bearer 0
MSGc:      18      26
B:      239      237
M:      1      1
T:      23      42
R:      0      16
S:      0.0983      0.3781
L:      19536      5374
D:      1      1
I:      240      127
N:      240      254
         Counters
         Bearer 0
OHF:      2327912      997543
OHFErr:      201273      0
RS:      0      3223596
RSCorr:      0      3
RSUnCorr:   0      0

         Bearer 0
HEC:      264209      0
OCD:      6413      0
LCD:      6413      0
Total Cells:   591644711      0
Data Cells:   4185205      0
Drop Cells:   0
Bit Errors:   0      0

ES:      3772      0
SES:      9      0
UAS:      27      27
AS:      3960

         Bearer 0
INP:      0.00      0.00
INPRein:   0.00      0.00
delay:      0      0
PER:      1.70      3.98
OR:      112.81      64.22
AgR:      77839.93   20063.54

Bitswap:   1933/1934      0/0

Total time = 1 hours 6 min 27 sec
FEC:      0      3
CRC:      201273      0
ES:      3772      0
SES:      9      0
UAS:      27      27
LOS:      0      0
LOF:      0      0
LOM:      0      0
Latest 15 minutes time = 6 min 27 sec
FEC:      0      0
CRC:      12238      0
ES:      385      0
SES:      0      0
UAS:      0      0
LOS:      0      0
LOF:      0      0
LOM:      0      0
Previous 15 minutes time = 15 min 0 sec
FEC:      0      2
CRC:      35396      0
ES:      845      0
SES:      0      0
UAS:      0      0
LOS:      0      0
LOF:      0      0
LOM:      0      0
Latest 1 day time = 1 hours 6 min 27 sec
FEC:      0      3
CRC:      201273      0
ES:      3772      0
SES:      9      0
UAS:      27      27
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 = 1 hours 5 min 59 sec
FEC:      0      3
CRC:      201273      0
ES:      3772      0
SES:      9      0
UAS:      0      0
LOS:      0      0
LOF:      0      0
LOM:      0      0

Not sure if G.INP is enabled. Looking at others output, people had G.INP information which I can't find in the DSL stats output. Looking at xdslcmd vendor information, it is broadcom/Huawei backend.

I would appreciate any advise on how to proceed with this. Ideally I would like to use the HG612 with my own router rather than HH6.

[burakkucat]

Welcome to the Kitz forum. 

Had BT Infinity installed today and it came with HH6. Swapped it with a HG612 and started seeing packet loss.

Looking at DSL stats, seeing a lot of CRC errors and some ES errors.

A newly provisioned circuit will be operating with a "wide-open" profile, on fast-path. So CRCs and ES will be seen. After the first 24 hours have elapsed, the DLM process will then start gathering data as to the circuit's performance. If the DLM deems it necessary, it will then intervene to stabilise and to optimise the circuit's operation. 

Not sure if G.INP is enabled. Looking at others output, people had G.INP information which I can't find in the DSL stats output. Looking at xdslcmd vendor information, it is broadcom/Huawei backend.

I would appreciate any advise on how to proceed with this. Ideally I would like to use the HG612 with my own router rather than HH6.

I can confirm that G.998.4 (originally known as G.Inp) is currently not applied to your circuit. As your circuit terminates on a Huawei DSLAM, the DLM process could apply G.998.4 to your circuit if it would be beneficial.

Using a Huawei HG612 as a pure bridge modem, what do you have connected as the router device? Any device with an EWAN port could be used.

[mls2992a]

Thanks Kitz has a lot of information regarding HG612 and is really helpful.

A newly provisioned circuit will be operating with a "wide-open" profile, on fast-path. So CRCs and ES will be seen. After the first 24 hours have elapsed, the DLM process will then start gathering data as to the circuit's performance. If the DLM deems it necessary, it will then intervene to stabilise and to optimise the circuit's operation.

Didn't know that. I was under the understanding that DLM kicks in straight away. Will have to wait and see. hopefully packet losses gets fixed once DLM kicks in.

Coming from Virgin media, latency is amazing, under 10ms to google when Virgin is double that.

I can confirm that G.998.4 (originally known as G.Inp) is currently not applied to your circuit. As your circuit terminates on a Huawei DSLAM, the DLM process could apply G.998.4 to your circuit if it would be beneficial.

What should I be looking for in stats to see if G.998.4/G.INP has kicked in or not?

Using a Huawei HG612 as a pure bridge modem, what do you have connected as the router device? Any device with an EWAN port could be used.

running pfsense as a VM on proxmox

Slightly offtopic, is HG612 still considered the best modem for VDSL? Considering the fact, the last DSL firmware update was in 2015 and I believe BT Openreach doesn't provide with new installs anymore.

Also the ports on HG612 are limited to 100Mbps. So I can't enable 1508 MTU for pppoe on pfsense as Intel recommends not to enable baby Jumbo frames (aka 1508 MTU) with the Intel NIC I have. Was able to get around it by running it through a gigabit switch as suggested in this article - https://blog.kingj.net/2017/02/12/how-to/baby-jumbo-frames-rfc-4638-with-igb-based-nics-on-pfsense/

[roseway]

What should I be looking for in stats to see if G.998.4/G.INP has kicked in or not?

The easy way is to look in the stats to see if there is a reference to Bearer 1. Looking at your stats in your opening message, only Bearer 0 is there, so you haven't got G.Inp enabled at present.

[burakkucat]

. . . I was under the understanding that DLM kicks in straight away.

You will find a definitive statement in Section 2.2.1, headed "Dynamic Line Management", of BT SIN498 v7.3.

running pfsense as a VM on proxmox

Ah, I see. Thank you.

Slightly offtopic, is HG612 still considered the best modem for VDSL? Considering the fact, the last DSL firmware update was in 2015 and I believe BT Openreach doesn't provide with new installs anymore.

It is always useful to have a spare HG612 available, just in case of "one of those moments". 

Take a look at the very first post of this thread. I will suggest that you research the various ZyXEL devices, at the bottom of that list. A number of members use such devices; some configured just as a pure-bridge modem, others configured at a full all-in-one box.

[WWWombat]

The "Since Link Time" set of statistics looks rather worrying. 3,772 errored seconds means that CRCs happened in pretty much every single second of the 1 hour 6 minutes (3,960 seconds) of link uptime. And, with 201,000 CRCs in that time, that comes out to be very close to 50 CRCs per second ... very close to the 50 Hz AC rate of mains.

If that isn't electrically-induced noise, it is one heck of a coincidence.

When DLM intervenes, I would hope that it does so by turning on G.INP. It seems likely that such noise is easily dealt with - either by the (minimal) FEC/interleaving that comes with G.INP, or the retransmission.

Unfortunately, the high ES count that is accumulating *might* cause DLM to turn on a full FEC/interleaving intervention without G.INP. Fingers crossed this doesn't happen.

[mls2992a]

The "Since Link Time" set of statistics looks rather worrying. 3,772 errored seconds means that CRCs happened in pretty much every single second of the 1 hour 6 minutes (3,960 seconds) of link uptime. And, with 201,000 CRCs in that time, that comes out to be very close to 50 CRCs per second ... very close to the 50 Hz AC rate of mains.

If that isn't electrically-induced noise, it is one heck of a coincidence.

You sir, are an absolute legend. This is what appears to be happening. The modem was sitting on top of a Netgear PoE switch and when I moved it away to a place with no other equipment nearby, CRC errors dropped massively.

Thank you for your help. Really appreciate it

Have been dealing with BT for a week on this and even had an engineer come out.

Once DLM kicked in, it kept dropping the line sync rate every day until BT engineer did a reset. BT engineer came out and did line tests which came out clean but when he ran VDSL tests on his device, he only got 39 Mbps down. So he went ahead and did a DLM reset. It was done yesterday so hopefully, DLM should kick in tomorrow and should see better results. Also, once FEC is enabled, it should help with CRC errors as well.

BT have an SFI engineer scheduled for Friday as even they were puzzled with actual speeds being so low when underlying line syncs at 70+ with the exchange. Maybe his visit isn't needed anymore. I will wait until Thursday to see how it goes before canceling the appointment.

BT HH6 doesn't seem to be affected by noise. Maybe it has better isolation compared to HG612. BT don't seem to be offering Modem mode like Virgin media does.

Latest stats

Code: [Select]

# xdslcmd info --stats
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Last initialization procedure status: 0
Max: Upstream rate = 32261 Kbps, Downstream rate = 80648 Kbps
Bearer: 0, Upstream rate = 19999 Kbps, Downstream rate = 79987 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): 6.5 15.3
Attn(dB): 12.8 0.0
Pwr(dBm): 12.7 1.1
VDSL2 framing
Bearer 0
MSGc: 18 26
B: 239 237
M: 1 1
T: 23 42
R: 0 16
S: 0.0955 0.3781
L: 20104 5374
D: 1 1
I: 240 127
N: 240 254
Counters
Bearer 0
OHF: 2364758 985017
OHFErr: 1298 1
RS: 0 2697763
RSCorr: 0 15
RSUnCorr: 0 0

Bearer 0
HEC: 129 0
OCD: 3 0
LCD: 3 0
Total Cells: 601284678 0
Data Cells: 15771772 0
Drop Cells: 0
Bit Errors: 0 0

ES: 698 1
SES: 0 0
UAS: 23 23
AS: 3910

Bearer 0
INP: 0.00 0.00
INPRein: 0.00 0.00
delay: 0 0
PER: 1.65 3.98
OR: 116.09 64.22
AgR: 80103.09 20063.54

Bitswap: 1359/1359 0/0

Total time = 1 hours 5 min 33 sec
FEC: 0 15
CRC: 1298 1
ES: 698 1
SES: 0 0
UAS: 23 23
LOS: 0 0
LOF: 0 0
LOM: 0 0
Latest 15 minutes time = 5 min 33 sec
FEC: 0 0
CRC: 85 0
ES: 64 0
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
LOM: 0 0
Previous 15 minutes time = 15 min 0 sec
FEC: 0 3
CRC: 319 0
ES: 157 0
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
LOM: 0 0
Latest 1 day time = 1 hours 5 min 33 sec
FEC: 0 15
CRC: 1298 1
ES: 698 1
SES: 0 0
UAS: 23 23
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 = 1 hours 5 min 9 sec
FEC: 0 15
CRC: 1298 1
ES: 698 1
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
LOM: 0 0

It is always useful to have a spare HG612 available, just in case of "one of those moments". 

Take a look at the very first post of this thread. I will suggest that you research the various ZyXEL devices, at the bottom of that list. A number of members use such devices; some configured just as a pure-bridge modem, others configured at a full all-in-one box.

I am keeping the HG612 modem. Was wondering if newer modem provided better performance compared to HG612. Also they have firmware updates which HG612 doesn't.

Is there a reason why Draytek 130 VDSL modem isn't on the list? For a modem use case, it only costs £81 on Amazon compared to paying £100+ for VDSL router that I am only going to be using in bridge mode

[burakkucat]

Is there a reason why Draytek 130 VDSL modem isn't on the list?

The Draytek Vigor 130? No, I have no idea. 

It doesn't use a Broadcom chipset, so any of the usual statistics harvesting utilities cannot be used. However I do know that underzone uses one and is happy with its performance.