Marcelo is trying to help you to simply disable IPv6, this can improve things substantially.
Disabling some settings can improve performance of the RUT. These tweaks have helped to resolve problems successfully for a good few people. I, personally, have no idea why nor do i understand why, and i don’t want to… but my own experience is that it works for me, and that’s good enough. I’m sure that Marcelo’s explanation is excellent, having read it i find myself reaching for the bottle of brandy as it’s too much for my pea sized brain to grasp. Sometimes is just best not to know why in toooo much depth but just accept it works.
To disable IPv6 navigate the RUT’s user interface to page: Network > WAN and then click / tap to “EDIT” your mob1s1a1 interface. Save & Apply Twice.
Then do: Network > LAN
Then turn off VoLTE.
Save & Apply at each stage, sometimes twice which is a bit of a puzzle. I would then reboot.
