This issue doesn't seem related to the GRE tunnel issues which were related to the equipment actually terminating the tunnel.

In reply to a post by anthonyshapley:

However the Engineer on the call said he had witnessed this intermittent connection issue and it was likely a switch - could I texted him every time it went down/up - as I am experiencing 100% packet loss for 5-30 seconds every few hours.

I would chase down the DOCSIS errors on the physical cable plant. If the coax network is coming apart then that will drive disconnections and make any GRE related problems hard to identify.

In reply to a post by jchamier:

In reply to a post by anthonyshapley:

However the Engineer on the call said he had witnessed this intermittent connection issue and it was likely a switch - could I texted him every time it went down/up - as I am experiencing 100% packet loss for 5-30 seconds every few hours.

I would chase down the DOCSIS errors on the physical cable plant. If the coax network is coming apart then that will drive disconnections and make any GRE related problems hard to identify.

They are below:

Docsis Logs
No. Time Type Priority Event
1 09/07/20 09:45:31 90000000 warning MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1;CM-MAC=bc:3e:07:bf:0a:40;CMTS-MAC=00:01:5c:86:84:6e;CM-QOS=1.1;CM-VER=3.0;
2 09/07/20 09:45:39 73040100 notice TLV-11 - unrecognized OID;CM-MAC=bc:3e:07:bf:0a:40;CMTS-MAC=00:01:5c:86:84:6e;CM-QOS=1.1;CM-VER=3.0;
3 09/07/20 11:15:58 90000000 warning MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1;CM-MAC=bc:3e:07:bf:0a:40;CMTS-MAC=00:01:5c:86:84:6e;CM-QOS=1.1;CM-VER=3.0;
4 09/07/20 11:16:07 73040100 notice TLV-11 - unrecognized OID;CM-MAC=bc:3e:07:bf:0a:40;CMTS-MAC=00:01:5c:86:84:6e;CM-QOS=1.1;CM-VER=3.0;
5 09/11/20 12:54:23 82000200 critical No Ranging Response received - T3 time-out;CM-MAC=bc:3e:07:bf:0a:40;CMTS-MAC=00:01:5c:86:84:6e;CM-QOS=1.1;CM-VER=3.0;
6 09/12/20 22:30:25 68010100 error DHCP RENEW sent - No response for IPv4;CM-MAC=bc:3e:07:bf:0a:40;CMTS-MAC=00:01:5c:86:84:6e;CM-QOS=1.1;CM-VER=3.0;
7 09/12/20 23:35:17 82000200 critical No Ranging Response received - T3 time-out;CM-MAC=bc:3e:07:bf:0a:40;CMTS-MAC=00:01:5c:86:84:6e;CM-QOS=1.1;CM-VER=3.0;
8 09/13/20 14:14:27 68010100 error DHCP RENEW sent - No response for IPv4;CM-MAC=bc:3e:07:bf:0a:40;CMTS-MAC=00:01:5c:86:84:6e;CM-QOS=1.1;CM-VER=3.0;
9 09/13/20 14:15:26 68010400 error DHCP REBIND WARNING - Field invalid in response;CM-MAC=bc:3e:07:bf:0a:40;CMTS-MAC=00:01:5c:86:84:6e;CM-QOS=1.1;CM-VER=3.0;
10 01/01/70 00:01:42 82000200 critical No Ranging Response received - T3 time-out;CM-MAC=bc:3e:07:bf:0a:40;CMTS-MAC=00:01:5c:86:84:6e;CM-QOS=1.1;CM-VER=3.0;
11 09/15/20 09:37:02 90000000 warning MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1;CM-MAC=bc:3e:07:bf:0a:40;CMTS-MAC=00:01:5c:86:84:6e;CM-QOS=1.1;CM-VER=3.0;
12 09/15/20 09:37:08 73040100 notice TLV-11 - unrecognized OID;CM-MAC=bc:3e:07:bf:0a:40;CMTS-MAC=00:01:5c:86:84:6e;CM-QOS=1.1;CM-VER=3.0;
13 09/18/20 13:43:55 82000200 critical No Ranging Response received - T3 time-out;CM-MAC=bc:3e:07:bf:0a:40;CMTS-MAC=00:01:5c:86:84:6e;CM-QOS=1.1;CM-VER=3.0;
14 09/19/20 15:31:14 90000000 warning MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1;CM-MAC=bc:3e:07:bf:0a:40;CMTS-MAC=00:01:5c:86:84:6e;CM-QOS=1.1;CM-VER=3.0;
15 09/19/20 15:31:20 73040100 notice TLV-11 - unrecognized OID;CM-MAC=bc:3e:07:bf:0a:40;CMTS-MAC=00:01:5c:86:84:6e;CM-QOS=1.1;CM-VER=3.0;
16 09/22/20 09:14:34 82000200 critical No Ranging Response received - T3 time-out;CM-MAC=bc:3e:07:bf:0a:40;CMTS-MAC=00:01:5c:86:84:6e;CM-QOS=1.1;CM-VER=3.0;
17 09/25/20 03:42:50 68010100 error DHCP RENEW sent - No response for IPv4;CM-MAC=bc:3e:07:bf:0a:40;CMTS-MAC=00:01:5c:86:84:6e;CM-QOS=1.1;CM-VER=3.0;
18 09/25/20 03:43:42 68010400 error DHCP REBIND WARNING - Field invalid in response;CM-MAC=bc:3e:07:bf:0a:40;CMTS-MAC=00:01:5c:86:84:6e;CM-QOS=1.1;CM-VER=3.0;
19 09/27/20 16:34:57 82000200 critical No Ranging Response received - T3 time-out;CM-MAC=bc:3e:07:bf:0a:40;CMTS-MAC=00:01:5c:86:84:6e;CM-QOS=1.1;CM-VER=3.0;
20 09/29/20 11:08:36 68010100 error DHCP RENEW sent - No response for IPv4;CM-MAC=bc:3e:07:bf:0a:40;CMTS-MAC=00:01:5c:86:84:6e;CM-QOS=1.1;CM-VER=3.0;

I'll be honest, doesn't mean a lot to me! Any insights would be appreciated though as the Engineer is coming tomorrow.

In reply to a post by anthonyshapley:

I'll be honest, doesn't mean a lot to me! Any insights would be appreciated though as the Engineer is coming tomorrow.

The message: "No Ranging Response received - T3 time-out" means the modem lost contact across the cable network with the head end equipment. You are getting a few a week, but not constantly.

Make sure you point them out to the engineer.

In reply to a post by jchamier:

In reply to a post by anthonyshapley:

I'll be honest, doesn't mean a lot to me! Any insights would be appreciated though as the Engineer is coming tomorrow.

The message: "No Ranging Response received - T3 time-out" means the modem lost contact across the cable network with the head end equipment. You are getting a few a week, but not constantly.

Make sure you point them out to the engineer.

I will - thank you for pointing that out.

Looks a lot like my VMB connection BQM used to. High latency/timeouts all day long. It turned out to be a signal power issue, and was corrected by moving my cable to a higher powered port in the cabinet I believe, as my cable length was a little longer than they anticipated when I was connected. It didn't change the speed at all, but definitely improved response times. If you haven't already, have a look at the signal power levels for both upstream and downstream, and see if they are within specified ranges (Google what they are meant to be). The hardest part will be convincing the Philippines based customer service that an engineer needs to check it out, because as far as they are concerned if it is connected everything is fine, but stress it to them and they should send someone eventually, who should be able to spot any power issues straight away with a visit.

The occasional T3 is fine and happens even on really good plant. As long as there aren't tons of them it's okay. T4s are the really bad one.

Any issues with excessive T3s usually indicate upstream issues which most of the time cannot be solved at the property but need network work.

Thanks for the info, very useful! Do you have any tips on "SYNC Timing synchronisation failure - loss of sync" and "RCS partial service" - or are these secondary to a T3 / T4 event?

Those are downstream issues usually.

RCS = Receive Channel Set. Modem unable to lock to all downstream channels in the RCS due to RF impairments or other issues.

SYNC Timing... disconnection. Again usually downstream issues. Modem has lost synchronisation with downstream channels.

If you see a T4 timeout this is a disconnection and may be due to extensive upstream issues. A series of T3 timeouts becomes a T4 and results in disconnection and reconnection. Modem will indicate T4 timeout and that it's restarting the cable interface.