Virgin Media Community

[mrhcarlin]

I'm admittedly jumping the gun a bit here because it's literally just happened and I should probably wait until the morning, but I wanted to get the ball rolling just in case.

At about 22:30 we lost Internet, and then the Hub started flashing in different ways.

• Solid green WiFi light. (This doesn't seem to change.) Connecting to the WiFi is still possible.
• Base light will flash green for several seconds, while the Internet light stays off.
• Base light will go solid green, while the Internet light flashes green for several seconds.

I rebooted the Hub manually, even waited for a couple minutes to let it cool, but no dice. Nothing has interfered with the Hub and the coax cable is firm.

Any ideas?

Internet access says "Access denied" on the Hub admin page.

Time Priority Description

06/05/2021 23:29:44	Warning!	Lost MDD Timeout;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
06/05/2021 23:29:38	Error	RCS Primary DS Failure;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
06/05/2021 23:29:38	critical	SYNC Timing Synchronization failure - Failed to receive MAC SYNC frame within time-out period;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
06/05/2021 23:29:22	critical	No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
06/05/2021 23:28:53	Warning!	Lost MDD Timeout;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
06/05/2021 23:28:48	Error	RCS Primary DS Failure;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
06/05/2021 23:28:48	critical	SYNC Timing Synchronization failure - Failed to receive MAC SYNC frame within time-out period;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
06/05/2021 23:28:16	critical	No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
06/05/2021 23:27:43	Warning!	Lost MDD Timeout;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
06/05/2021 23:27:39	notice	LAN login Success;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
06/05/2021 23:27:37	Error	RCS Primary DS Failure;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
06/05/2021 23:27:37	critical	SYNC Timing Synchronization failure - Failed to receive MAC SYNC frame within time-out period;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
06/05/2021 23:27:22	critical	No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
06/05/2021 23:26:55	Warning!	Lost MDD Timeout;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
06/05/2021 23:26:49	Error	RCS Primary DS Failure;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
06/05/2021 23:26:49	critical	SYNC Timing Synchronization failure - Failed to receive MAC SYNC frame within time-out period;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
06/05/2021 23:26:31	critical	No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
06/05/2021 23:26:5	Warning!	Lost MDD Timeout;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
06/05/2021 23:25:59	Error	RCS Primary DS Failure;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
06/05/2021 23:25:59	critical	SYNC Timing Synchronization failure - Failed to receive MAC SYNC frame within time-out period;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

[mrhcarlin]

Ok so I turned off the Hub for about 15 minutes, re-tightened the coax at both ends just to make doubly sure, and then after turning it back on I've got Internet again (after the usual millennia that it takes for the Hub to properly come back online). Knock wood that it doesn't go weird again!

Curious to know now what might have caused that "blip" though...

[lotharmat]

Could be noise preventing a connection!

[mrhcarlin]

Like electronic devices, wires, power cables etc near the Hub, or something on the line out of my control? My Hub does sit next to a surge protector and is fairly close to my TV, but I've had it this way for months without any similar issues.

Is there any way to know for sure what it could be (and hopefully fix it) or will I have to live in fear that my Hub could randomly go on the fritz again? 😛

[lotharmat]

It'll be worth posting up your Hub stats! (Upstream and Downstream)

If it is a noise issue - you'll likely see it in there!

[mrhcarlin]

Downstream bonded channels

Channel Frequency (Hz) Power (dBmV) SNR (dB) Modulation Channel ID

1	139000000	-4	37	256 qam	1
2	147000000	-4.2	37	256 qam	2
3	155000000	-4.7	37	256 qam	3
4	163000000	-5	37	256 qam	4
5	171000000	-5.2	36	256 qam	5
6	179000000	-5.5	37	256 qam	6
7	187000000	-5.5	36	256 qam	7
8	195000000	-5.5	37	256 qam	8
9	203000000	-5.7	36	256 qam	9
10	211000000	-5.7	36	256 qam	10
11	219000000	-5.9	36	256 qam	11
12	227000000	-6	36	256 qam	12
13	235000000	-6	36	256 qam	13
14	243000000	-6.2	36	256 qam	14
15	251000000	-6.4	36	256 qam	15
16	259000000	-6.9	36	256 qam	16
17	267000000	-7	36	256 qam	17
18	275000000	-6.5	36	256 qam	18
19	283000000	-6	37	256 qam	19
20	291000000	-6	37	256 qam	20
21	299000000	-6.2	36	256 qam	21
22	307000000	-6.2	37	256 qam	22
23	315000000	-6	37	256 qam	23
24	323000000	-6.2	37	256 qam	24

Downstream bonded channels

Channel Locked Status RxMER (dB) Pre RS Errors Post RS Errors

1	Locked	37.6	23	0
2	Locked	37.6	49	0
3	Locked	37.3	42	0
4	Locked	37.3	43	0
5	Locked	36.6	38	0
6	Locked	37.3	22	0
7	Locked	36.6	31	0
8	Locked	37.3	20	0
9	Locked	36.6	17	0
10	Locked	36.6	22	0
11	Locked	36.6	29	0
12	Locked	36.6	27	0
13	Locked	36.6	29	0
14	Locked	36.6	29	0
15	Locked	36.6	25	0
16	Locked	36.3	47	0
17	Locked	36.6	27	0
18	Locked	36.6	21	0
19	Locked	37.3	19	0
20	Locked	37.3	19	0
21	Locked	36.6	29	0
22	Locked	37.3	24	0
23	Locked	37.3	37	0
24	Locked	37.3	34	0

Upstream bonded channels

Channel Frequency (Hz) Power (dBmV) Symbol Rate (ksps) Modulation Channel ID

1	60300322	50	5120	64 qam	1
2	46200283	49.8	5120	64 qam	3
3	39400063	50	5120	64 qam	4
4	53700019	49.8	5120	64 qam	2

Upstream bonded channels

Channel Channel Type T1 Timeouts T2 Timeouts T3 Timeouts T4 Timeouts

1	ATDMA	0	0	0	0
2	ATDMA	0	0	0	0
3	ATDMA	0	0	0	0
4	ATDMA	0	0	0	0

[lotharmat]

Downstream power looks to be a little low - (should be within -6 to 10 dBmV)

Do you know if you have any attenuators fitted?

[gary_dexter]

Downstream power levels are too low and upstream on the verge of being too high.

Unless there's an area issue you'll need an engineer.

[mrhcarlin]

---

@gary_dexter wrote:
Downstream power levels are too low and upstream on the verge of being too high.

Unless there's an area issue you'll need an engineer.

---

What's the best way to go about this? Last year when there were issues affecting several postcodes near me, it took almost a week to resolve with the typical "we can't see any issues currently" spiel, so I don't have much hope for getting a potentially isolated issue resolved.

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@lotharmat wrote:
Downstream power looks to be a little low - (should be within -6 to 10 dBmV)

Do you know if you have any attenuators fitted?

---

Yes, there's a 6dB attenuator fitted to the coax just before it goes into the Hub.

---

I don't know if it makes a difference to my apparent power issues (or if this even effects it), but besides last night my connection is always stable and I get good latency and jitter when testing with https://librespeed.org/ and good download speeds in general