Intermittent Disconnects and Packet Loss

[MWrycraft]

After tweeting VM they advised me to post here for support.  

Background - I have been having intermittent issues with my 350 Broadband connection for months now.  The symptoms are disconnects, very slow reconnects (especially DNS look ups) and sometimes 0MPS uploads.  
I have had numerous issues with the cabinet in the street and have been told by various VM engineers (when I can get them to come out!) that other engineers are moving connections around to fix problems or connect new customers (I don't know how true this is)
I have phoned support on a number of occasions and have had various levels of success (the worst - "Reboot your router I am SURE it will fix the problem!" - because I've not done that multiple times..)
My phone line also isn't working and VM said they would send out an engineer to look into that (they did). He also looked at the network and there were no issues - which is true <at the time>, but he did see enough to ask for a new fibre cable to be laid to my property...
On 9.11.2021 (last Tuesday) engineers laid down the cable and things were fine until Thursday the 11.11 when the issues re-occurred, and have been choppy ever since.  

I have set up a Thinkbroadband BQM
And this is from this evening for the last 24 hours.  

Saturday was particularly bad:

For context here is the day (9.11) they severed my connection and connected me to the new cable (ironically, I hadn't had any issues on the day leading up to that!) 

Notes:

My Hub is (now - I changed this weeks ago to help in troubleshooting) in Modem mode (where the external IP terminates there, rather on the ASUS router I use)
The BQM is showing connection health to the Hub, not my internal network. 

Power levels on the Hub (I think!) are ok, but there are low levels of post RS errors:

Downstream bonded channels

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

1	515000000	-5.9	37	256 qam	37
2	235000000	-6.2	37	256 qam	13
3	243000000	-6.7	37	256 qam	14
4	251000000	-7.5	37	256 qam	15
5	259000000	-8.4	37	256 qam	16
6	267000000	-8.2	37	256 qam	17
7	275000000	-7.7	37	256 qam	18
8	283000000	-7.2	37	256 qam	19
9	291000000	-6.9	37	256 qam	20
10	299000000	-6.5	37	256 qam	21
11	307000000	-6.5	37	256 qam	22
12	315000000	-6.4	38	256 qam	23
13	323000000	-6.2	38	256 qam	24
14	331000000	-6	38	256 qam	25
15	339000000	-6	38	256 qam	26
16	347000000	-5.9	38	256 qam	27
17	355000000	-5.5	38	256 qam	28
18	363000000	-5.2	38	256 qam	29
19	371000000	-5	38	256 qam	30
20	379000000	-5.2	38	256 qam	31
21	387000000	-6	38	256 qam	32
22	491000000	-6	37	256 qam	34
23	499000000	-6	38	256 qam	35
24	507000000	-5.9	37	256 qam	36

Downstream bonded channels

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

1	Locked	37.6	26818	62
2	Locked	37.6	2482	83
3	Locked	37.6	2368	72
4	Locked	37.3	3413	66
5	Locked	37.3	4159	106
6	Locked	37.3	4051	96
7	Locked	37.3	3743	134
8	Locked	37.6	3579	95
9	Locked	37.6	4402	88
10	Locked	37.3	4934	81
11	Locked	37.6	4693	16
12	Locked	38.6	5039	53
13	Locked	38.6	5733	65
14	Locked	38.6	5269	75
15	Locked	38.6	6147	95
16	Locked	38.6	6840	38
17	Locked	38.6	7106	83
18	Locked	38.9	7226	79
19	Locked	38.9	7170	73
20	Locked	38.6	9147	844
21	Locked	38.6	9980	73
22	Locked	37.6	27483	64
23	Locked	38.6	24621	53
24	Locked	37.3	26722	55

The network log shows various errors:

14/11/2021 15:37:55	Error	DHCP RENEW WARNING - Field invalid in response v4 option;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
11/11/2021 21:44:14	critical	No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
11/11/2021 18:18:15	Error	DHCP RENEW WARNING - Field invalid in response v4 option;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
09/11/2021 12:34:55	critical	No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
09/11/2021 12:24:38	critical	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
09/11/2021 12:21:57	Warning!	Lost MDD Timeout;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
09/11/2021 12:21:53	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
09/11/2021 12:21:52	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
09/11/2021 12:21:52	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

(Note I've only gone back as far as the new cable connection. 

My thoughts:
It looks like contention at the cabinet. - up to 10% pack loss explains the disconnects and slowness I have.  
Can VM please contact me (I'm bored of explaining this to new people every single time) with options please.  If the problem isn't happening at the time 'everything looks ok at the moment' is all I'm being told. 
Perhaps I need a new hub? 

A nice lady did try to sell me 1GB telling me that would fix it.  Thanks, but can we get this fixed first, or it's like you selling me a sports car and forcing me to drive to work at 8am on the M25 around London.

Finally, as an aside, I got an automated email yesterday telling me my phone line was fixed. It's not.  I'll be phoning (from my mobile!) again tomorrow...

[Andrew-G · Accepted solution]

Well, at the moment your main problem is downstream power levels are far too low.  Regarding that upgrading to 1 Gbps will solve it, no that would make it worse, and VM staff are lying to customers when they say this.

I'll flag this for staff to take a look at power levels, and for the agent to be traced and hopefully sacked.  I'm tired of heating customers report such dishonest practices, and clearly VM's management and culture are doing little to stop this.  

[Hayley_S]

Hello @MWrycraft,

Welcome back! Thanks for posting.

I am sorry to see that you are having some downstream issues.

I located your account and can see this also, I will send you a private message so I can get a tech booked for you.

Many thanks,