Virgin Media Community

[tehwolf]

So, I think i kinda know what the outcome is going to be, but I wanna post this up anyways to get some feedback on my connection as you lot know a lot more than i do about this stuff 🙂

My VM connection is broadly stable - don't have many noticeable issues with either speed or latency. I am on the 200mb service with a hub2ac, running in modem mode, terminating the coax connection.

From the reading i've done, particularly from a recent post by @andruser (very informative) as far as i can tell, all of my power levels and general stats are within spec and nothing to complain about, but one of my four upstream channels struggles to negotiate/maintain a QAM of 64 and I do get issues from time to time..

I've had a BQM up and running for several weeks and it doesn't look terrible, but i do get some packet loss from time to time and i'd (obviously) like to eliminate it if possible..

This is an example of a typical day.. (workday whilst WFH + three kids in various school-related google classroom/zoom sessions + me in teams calls etc..)

This is an example of a bad day. (workday)

This is an example of the intermittent packet loss that i see on my connection from time to time (i'd say one day in three - this particular graph was a Sunday, so no obvious workday traffic between 9 and 6)

Now, as i said at the top of my post - as far as i can see, everything is within spec from a power perspective, so I'm guessing VM would take one look at this and say that everything is ok from their end.. but presumably there's *something* that's not quite right, given the 32QAM and the post-RS errors?

Speaking of post-RS errors, I don't have huge numbers, but there's enough - the stats i'll post from the hub in the next post are after I did a reboot at about 7pm last night..

[tehwolf]

Cable Modem StatusItem Status Comments

Acquired Downstream Channel (Hz)	139000000	Locked
Ranged Upstream Channel (Hz)	32600000	Success
Provisioning State	OK	Operational

Downstream  DS-1 DS-2 DS-3 DS-4 DS-5 DS-6 DS-7 DS-8

Frequency (Hz)	139000000	147000000	155000000	163000000	171000000	179000000	187000000	195000000
Lock Status(QAM Lock/FEC Sync/MPEG Lock)	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked
Channel ID	1	2	3	4	5	6	7	8
Modulation	256QAM	256QAM	256QAM	256QAM	256QAM	256QAM	256QAM	256QAM
Symbol Rate (Msym/sec)	6.952000	6.952000	6.952000	6.952000	6.952000	6.952000	6.952000	6.952000
Interleave Depth	I=12 J=17	I=12 J=17	I=12 J=17	I=12 J=17	I=12 J=17	I=12 J=17	I=12 J=17	I=12 J=17
Power Level (dBmV)	5.18	5.23	5.21	4.96	4.74	4.32	4.09	4.16
RxMER (dB)	37.36	37.94	37.94	37.94	38.26	37.94	37.94	37.94
Pre RS Errors	6379	5026	623	344	298	297	932	316
Post RS Errors	299	271	317	278	297	294	931	316

[tehwolf]

Upstream  US-1 US-2 US-3 US-4

Channel Type	2.0	2.0	2.0	2.0
Channel ID	5	4	3	6
Frequency (Hz)	32600000	39400000	46200000	25800000
Ranging Status	Success	Success	Success	Success
Modulation	64QAM	64QAM	64QAM	32QAM
Symbol Rate (Sym/sec)	5120000	5120000	5120000	5120000
Mini-Slot Size	2	2	2	2
Power Level (dBmV)	46.25	47.00	47.75	45.75
T1 Timeouts	0	0	0	0
T2 Timeouts	0	0	0	0
T3 Timeouts	2	0	0	0
T4 Timeouts	0	0	0	0

[tehwolf]

Network Log

First Time	Last Time	Priority	Error Number	Description
18/01/2021 19:54:08 GMT	18/01/2021 19:54:08 GMT	Error (4)	68000407	TOD established
Time Not Established	Time Not Established	Critical (3)	82000200	No Ranging Response received - T3 time-out
Time Not Established	Time Not Established	Critical (3)	82000200	No Ranging Response received - T3 time-out
Time Not Established	Time Not Established	Notice (6)	84000510	Downstream Locked Successfully
Time Not Established	Time Not Established	Notice (6)	84000510	Downstream Locked Successfully
18/01/2021 16:27:29 GMT	18/01/2021 16:27:29 GMT	Error (4)	68010300	DHCP RENEW WARNING - Field invalid in response v4 option
15/01/2021 06:52:47 GMT	15/01/2021 06:52:47 GMT	Error (4)	68010300	DHCP RENEW WARNING - Field invalid in response v4 option
12/01/2021 00:44:33 GMT	12/01/2021 00:44:33 GMT	Critical (3)	82000200	No Ranging Response received - T3 time-out
12/01/2021 00:44:32 GMT	12/01/2021 00:44:32 GMT	Critical (3)	82000200	No Ranging Response received - T3 time-out
12/01/2021 00:44:31 GMT	12/01/2021 00:44:31 GMT	Critical (3)	82000200	No Ranging Response received - T3 time-out
12/01/2021 00:44:30 GMT	12/01/2021 00:44:30 GMT	Critical (3)	82000200	No Ranging Response received - T3 time-out
12/01/2021 00:44:28 GMT	12/01/2021 00:44:28 GMT	Critical (3)	82000200	No Ranging Response received - T3 time-out
12/01/2021 00:44:27 GMT	12/01/2021 00:44:27 GMT	Critical (3)	82000200	No Ranging Response received - T3 time-out
12/01/2021 00:44:26 GMT	12/01/2021 00:44:26 GMT	Critical (3)	82000200	No Ranging Response received - T3 time-out
12/01/2021 00:44:25 GMT	12/01/2021 00:44:25 GMT	Critical (3)	82000200	No Ranging Response received - T3 time-out
12/01/2021 00:44:23 GMT	12/01/2021 00:44:23 GMT	Critical (3)	82000200	No Ranging Response received - T3 time-out
12/01/2021 00:44:22 GMT	12/01/2021 00:44:22 GMT	Critical (3)	82000200	No Ranging Response received - T3 time-out
12/01/2021 00:44:21 GMT	12/01/2021 00:44:21 GMT	Critical (3)	82000200	No Ranging Response received - T3 time-out
12/01/2021 00:44:20 GMT	12/01/2021 00:44:20 GMT	Critical (3)	82000200	No Ranging Response received - T3 time-out
12/01/2021 00:44:19 GMT	12/01/2021 00:44:19 GMT	Critical (3)	82000200	No Ranging Response received - T3 time-out

[tehwolf]

So, upstream speeds cut in half this evening, 

Live BQM here:

QAM on one of my upstream channels dropped to 16, too. 

Upstream  US-1 US-2 US-3 US-4

Channel Type	2.0	2.0	2.0	2.0
Channel ID	5	4	3	6
Frequency (Hz)	32600000	39400000	46200000	25800000
Ranging Status	Success	Success	Success	Success
Modulation	64QAM	64QAM	64QAM	16QAM
Symbol Rate (Sym/sec)	5120000	5120000	5120000	5120000
Mini-Slot Size	2	2	2	2
Power Level (dBmV)	46.25	47.00	47.75	45.71
T1 Timeouts	0	0	0	0
T2 Timeouts	0	0	0	0
T3 Timeouts	2	0	0	0
T4 Timeouts	0	0	0	0

Downstream table below - 

Downstream  DS-1 DS-2 DS-3 DS-4 DS-5 DS-6 DS-7 DS-8

Frequency (Hz)	139000000	147000000	155000000	163000000	171000000	179000000	187000000	195000000
Lock Status(QAM Lock/FEC Sync/MPEG Lock)	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked
Channel ID	1	2	3	4	5	6	7	8
Modulation	256QAM	256QAM	256QAM	256QAM	256QAM	256QAM	256QAM	256QAM
Symbol Rate (Msym/sec)	6.952000	6.952000	6.952000	6.952000	6.952000	6.952000	6.952000	6.952000
Interleave Depth	I=12 J=17	I=12 J=17	I=12 J=17	I=12 J=17	I=12 J=17	I=12 J=17	I=12 J=17	I=12 J=17
Power Level (dBmV)	4.87	4.95	4.95	4.68	4.36	4.05	3.78	3.86
RxMER (dB)	37.36	37.64	37.94	37.64	37.94	37.94	37.94	37.94
Pre RS Errors	17253	14006	1134	542	298	297	933	316
Post RS Errors	299	271	317	278	297	294	931	316

[tehwolf]

Interestingly, no further increase in post-RS errors since my previous post (counters haven't been reset and the hub hasn't been rebooted).

Network log also remains unchanged from my previous post, so won't post that again.. 

No area issues reported + connections checked and confirmed "finger tight" 

;/

[Paul_DN]

Hi tehwolf,

Thank you for reaching back out to us with your update, how have things been since your last post on Wednesday?

I have had a look our end and cannot see any issues at all, your levels are all where expected.

Regards

Paul.

[tehwolf]

Thanks for the reply.

no change, still one channel that is unable to negotiate a QAM of 64 and flips between 16 and 32, when at 16 upload speed halves and latency increases - most noticeable when I join a teams meeting, I can tell the QAM has dropped when it takes several seconds to join a meeting...

it’s otherwise stable though. 

[Paul_DN]

Hi tehwolf, 

Thanks for coming back to me I can see you do have one of our older routers the 2ac and it looks like you have a 3rd party router, I have looked and I can see one of your Quan is incorrect, I advise putting our router back into router mode and perform a pin reset, also check all youe external and internal cables are hand tight.

Regards

Paul.

[tehwolf]

Thanks Paul,

I am indeed using an older router with a 3rd party device behind it. 

accept that you guys only support router mode etc, though I don’t see how connection negotiation on the WAN  side could be affected by being in one or other mode.. the modem is the modem and the cables are the cables, makes no difference (in my head at least - though happy to be schooled) whether the hub operates as a modem or a modem+router.

Ill pass on this for now - I don’t see how a reset / check in router mode does anything for me - unless it’s a mandatory step of the troubleshooting process before any other steps can be taken...