Multiple servers

Hey,

I was wondering if anyone have any experience with handling multiple server setups. So the setup will be like this:
1 server handle the login to the game
1 server handle the chat in the game
1 server handle the logic of the game and the matchmaking

So lets start with some basic info:
UDP + TCP does not go well together so all of them have to be UDP as UDP makes TCP loose packets. The chat server then gotta be coded with a reliable layer on top of the UDP layer to make it behave almost...

Multiple servers