I have been told that IRC uses UDP for client to server communication and TCP for server to server communication (in the case of linked servers). It seems that TCP is the better transport layer protocol for text chat since you need a ensure the text gets to the server. Just because a client displays the text as being in the channel/on the server it doesn't mean the server actually received it.
It's clear that IRC uses UDP. Is UDP used to pass the text messages from client to server?