You are right about the DHCP messages, they can safely be ignored.
The T3 messages are not too bad as long as they're not too frequent. What happens is that the Hub periodically sends out a ranging request message to the CMTS and waits for a response (basically an 'are you still there and should I be doing anything different' message). If it doesn't get a response back you get a T3 timeout. If it misses 16 (I think) in a row, then you get the T4 timeout and the Hub will reinitialise the network interface to try and reestablish the lock. This will manifest itself as a network connectivity loss.
Critically the logs don't show the successful ranging requests and responses, just the failures but if you look at the times they all seem fairly spaced out - sometimes the CMTS or the Hub are just too busy to responds properly and miss a message and this is generally nothing to worry about.
From the logs, I can't see anything critically wrong though, so what problems are you having with the Hub?
In this case, you have to think about your network connection, if you faced any electric issue then you have to solve it by an electrician. But if there any kind of problem regarding software issue then at first do one thing restart the router if then it's not working then check the LAN validity and wiring. After that do one thing restart your system and then it will work out. if it is no happens then check the printer connection with the router sometimes it faced the issue for the printer when I was using canon mg2922 then I faced the same problem for the printer.