Disconnection every 20 mins - Need help with logs


Hi all,
My connection is having a very strange behaviour, I get disconnected for some seconds every EXACTLY 20 minutes.
I made a small program that continuosly pings an host and exec a pathping when the problem occurs. I also installed wireshark and took the logs.
I tried to contact my ISP, also sending them the log obtained through wireshark, but for now they gave me no resolution. I suspect they changed something somewhere, cause this behaviour appeared for the first time only about two weeks ago.
I’m not a network expert so I don’t undestand the wireshark results, if anybody can take a look at the attached logs and see something wrong, please let me know. The problem occurs at entry no 2585.
I’ll appreciate any help, thanks in advance.