[Hiro]

it's a type of internet protocol for, from what i understand, is host-to-host connections through IPv4 or IPv6, so it's good for a lot of users making small requests, as opposed to TCP which isn't as time sensitive or useful to a large number of players, it's something about the difference between dropping packets or suspending them.

sometimes when you have a lot of packet loss, turning on UDP will make it so the packets don't have to be checked, so though it will come in in pieces, it will still get through. this may explain your shooting "glitch" which results from this. however, without the option, the player wouldn't be able to even play, and it doesn't affect everyone like that - sometimes nothing messes up from switching, though it seems to affect the sword detection or hitbox of everyone who switches.