I have been having an issue over the last couple of months where all of a sudden I was getting random drops to my internet connection throughout the day and evening. Unrelated to contention as the times would be even into the late evening / early mornings.
My setup I use the Hub 4 in Modem mode and have a Linksys WRT3200ACM with OpenWrt running on it. I have set up monitoring on the router. I have gone so far as to change the cable between the router and the hub, change the firmware of the router (Upgraded and downgraded), even change the router with another and still have the same issue. Virgin sent over an engineer and they replaced the Hub. The rest of the day the Hub was fine, then it looks like it must have got an update early one morning and reboot (As I could see this on the monitoring on the Router), and since then this issue has come back. Not as frequent, but from experience before, after rebooting the Hub it would work for about a week, but slowly the drops would become more frequent.
The monitoring I have in place is running pings to cloudflare DNS, Google DNS and the BBC website, and all drop out at the time this occurs. Also the logs on the router are showing that the link starts flapping at that time. It shows that the link to the hub drops and comes back numerous times over about a 30 seconds, though can last for about 2 minutes.
One time I saw this occur I was on the interface section of the OpenWRT gui and noticed that the IP address on the WAN port for the router changed from the usual Internet IP address to 192.168.100.1. This was for about a second or two and then flipped back to Internet IP address you would expect.
When the engineer came out, he did mention he had spoken to some customers he had been to that they had something like this, but could not confirm fully if this was the exact same issue, but sound close enough.
Is there some software/firmware update has been released to these hubs that potentially makes Modem Mode a little unstable? If there are any Virgin Media Technical people reading this I would happy to chat to them to if they would like to get more details on this.
Has anyone else had this type of behaviour over the last couple of months ?
Sorry for the long post.