Virgin Media Community

[JohnWin]

Hi

What does the message 'Cable Modem Reboot due to RG crash' mean and how can I stop it happening, or is it all at the VM end of  things?

My Hub 5 has crashed on a number of occasions over the past 2 weeks with this error report and it is really inconvenient.

Thanks

John

[Anonymous]

When you upgraded from a Hub 3 to a Hub 5 was an attenuator equaliser transferred to the new hub? If so try things without it connected for a while. 

[JohnWin]

Hi

I do have an attenuator that was removed from the Hub 3 when that was fitted, it is not connected to my Hub 5. Is it worth trying the connection with the attenuator fitted?

Thanks

John

[Anonymous]

You could give it a try. If no progress then remove it again. Engineers do sometimes forget them during hub changeovers. 

[JohnWin]

Hi

I tried that and it didn't help, in fact it failed to acquire the internet at all then. 

Does anyone have any other ideas?

Thanks

John

[Tudor]

Please post a full set of stats with the attenuator in place. 

How to get stats from a VM hub (no need to logon to the hub)

Open a web browser and go to 192.168.0.1 router mode or 192.168.100.1 modem mode

• Click on the “> Check router status” button
• Click on the “Downstream” tab, copy the text and paste into your reply, do not take a screen shot
• Click on the “Upstream” tab, copy the text and paste into your reply
• Click on the “Networking” tab, copy the text and paste into your reply.
• Do NOT post photos or screen shots they will be rejected as they contain MAC addresses. The board software will automatically change MAC addresses to **:** if done as above.

[JohnWin]

Hi

I managed to contact the help desk who say there is a fault in my connection so hopefully they will resolve it. I could not get any data with the attenuator in line because the router would not initialise.

I will hang on for 48 hours and see how the contact centre team perform and then post an update.

Here are the figures from the screen without the attenuator - (after having spoken to support):

Downstream bonded channels

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

1	139000000	15.6	42	QAM 256	1
2	147000000	15.4	42	QAM 256	2
3	155000000	15.1	42	QAM 256	3
4	163000000	14.8	42	QAM 256	4
5	171000000	14.8	42	QAM 256	5
6	179000000	14.7	42	QAM 256	6
7	187000000	14.5	42	QAM 256	7
8	195000000	14.6	42	QAM 256	8
9	203000000	14.3	42	QAM 256	9
10	211000000	14.2	42	QAM 256	10
11	219000000	13.8	42	QAM 256	11
12	227000000	13.6	42	QAM 256	12
13	235000000	13.2	42	QAM 256	13
14	243000000	13	42	QAM 256	14
15	251000000	12.7	42	QAM 256	15
16	259000000	12.3	41	QAM 256	16
17	267000000	12	42	QAM 256	17
18	275000000	11.7	41	QAM 256	18
19	283000000	12	41	QAM 256	19
20	291000000	12	41	QAM 256	20
21	299000000	11.9	41	QAM 256	21
22	307000000	11.8	41	QAM 256	22
23	315000000	11.7	41	QAM 256	23
24	323000000	11.5	41	QAM 256	24
25	331000000	11.1	41	QAM 256	25
26	339000000	11.1	41	QAM 256	26
27	347000000	11	41	QAM 256	27
28	355000000	10.8	41	QAM 256	28
29	363000000	10.8	41	QAM 256	29
30	371000000	10.9	41	QAM 256	30
31	379000000	10.9	41	QAM 256	31

Downstream bonded channels

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

1	Locked	42	0	0
2	Locked	42	0	0
3	Locked	42	0	0
4	Locked	42	0	0
5	Locked	42	0	0
6	Locked	42	0	0
7	Locked	42	0	0
8	Locked	42	0	0
9	Locked	42	0	0
10	Locked	42	0	0
11	Locked	42	0	0
12	Locked	42	0	0
13	Locked	42	0	0
14	Locked	42	0	0
15	Locked	42	0	0
16	Locked	41	0	0
17	Locked	42	0	0
18	Locked	41	0	0
19	Locked	41	0	0
20	Locked	41	0	0
21	Locked	41	0	0
22	Locked	41	0	0
23	Locked	41	0	0
24	Locked	41	0	0
25	Locked	41	0	0
26	Locked	41	0	0
27	Locked	41	0	0
28	Locked	41	0	0
29	Locked	41	0	0
30	Locked	41	0	0
31	Locked	41	0	0

Upstream bonded channels

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

0	49600000	36.8	5120	QAM 64	1
1	43100000	35.8	5120	QAM 64	2
2	36600000	35.3	5120	QAM 64	3
3	30100000	34.3	5120	QAM 64	4
4	23600000	33.8	5120	QAM 64	5

Upstream bonded channels

Channel Channel Type T1 Timeouts T2 Timeouts T3 Timeouts T4 Timeouts

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

Network Log

Time Priority Description

20-02-2023 12:51:26	notice	US profile assignment change. US Chan ID: 6; Previous Profile: 13; New Profile: 11 13.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
20-02-2023 12:51:26	warning	DBC-REQ Mismatch Between Calculated Value for P1.6hi Compared to CCAP Provided Value;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
20-02-2023 12:51:23	notice	REGISTRATION COMPLETE - Waiting for Operational status
20-02-2023 12:51:17	warning	RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
20-02-2023 12:51:17	warning	Dynamic Range Window violation
20-02-2023 12:51:17	warning	RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
20-02-2023 12:51:17	warning	REG-RSP-MP Mismatch Between Calculated Value for P1.6hi Compared to CCAP Provided Value;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
20-02-2023 12:51:17	warning	RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
20-02-2023 12:51:17	warning	Dynamic Range Window violation
20-02-2023 12:51:17	warning	Dynamic Range Window violation
20-02-2023 12:51:17	warning	RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
20-02-2023 12:51:17	warning	Dynamic Range Window violation
20-02-2023 12:51:12	notice	DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1 2 3.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
20-02-2023 12:51:00	warning	DHCP WARNING - Non-critical field invalid in response ;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
20-02-2023 12:50:57	notice	Honoring MDD; IP provisioning mode = IPv4
20-02-2023 12:50:48	critical	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
20-02-2023 12:50:36	critical	Cable Modem Reboot due to RG crash
20-02-2023 12:06:01	critical	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
20-02-2023 12:05:49	critical	Cable Modem Reboot due to RG crash
20-02-2023 12:00:01	critical	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
20-02-2023 12:00:01	critical	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
20-02-2023 11:59:49	critical	Cable Modem Reboot due to power button reset
20-02-2023 11:59:49	critical	Cable Modem Reboot due to power button reset
20-02-2023 11:49:43	critical	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
20-02-2023 11:49:32	critical	Cable Modem Reboot due to RG crash
20-02-2023 08:36:04	critical	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
20-02-2023 08:35:52	critical	Cable Modem Reboot due to RG crash
19-02-2023 22:13:54	critical	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
19-02-2023 22:13:42	critical	Cable Modem Reboot due to RG crash
17-02-2023 11:13:48	critical	No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
17-02-2023 11:13:18	critical	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
17-02-2023 11:13:06	critical	Cable Modem Reboot due to RG crash

Cable Modem StatusItem Status Comments

Acquired Downstream Channel(Hz)	139000000	Locked
Ranged Upstream Channel(Hz)	49600000	Ranged
Provisioning State	Online	Operational

Hopefully this information is useful

Thanks

John

[Anonymous · Accepted solution]

Downstream power levels are all way too high. Seems you will need some sort of attenuator. Let's see how it goes with support. 

[JohnWin]

Thanks for that - I will keep an eye on the levels and then let you know what happens once support have had a go - they said 24 - 48 hours for a resolve.

What levels would you expect for the downstream power levels?

Cheers

John

[Anonymous]

Below 8 ideally https://community.virginmedia.com/t5/Networking-and-WiFi/POWER-LEVELS-amp-SNR-A-TECHNICAL-PRIMER-upd...