* differences between connected and non-connected networking

    TCP vs UDP

        connection oriented (TCP) is like a phone call -- once a connection
        is established you've got bidirection communication flow until one
        or the other party hangs up; in-order and complete data; loss
        recovery can mean that data gets delayed; you may receive either
        partial messages or multiple messages in a single read

        connectionless (UDP) is like a letter (or a series of letter) --
        you recieve one message in its entirety, but (as with the postal
        service) letters can get lost or arrive out of order; also, you
        have no way to know that a letter was; a single receive always
        delivers a single complete message

    tracking active sessions

        TCP -- you need a connected socket for each client
               the call to accept happens at a point when data might not
               be available yet

        UDP -- you identify clients by addr,port
               if it's a new client, it _should_ be (must be?) a JOIN

    starting new sessions

        TCP -- you accept client socket #8, now what?
               to follow the protocol, you have to be able to handle more
               than 7 active clients sockets so that you can receive the
               JOIN and send FULL
               but how many connections without JOIN are you willing to
               keep around; and how long do you want to wait

        UDP -- when you receive a JOIN message and you've got too many,
               just send FULL (as per the spec)

* things to think about

    How should the server respond if it gets an out-of-order message?
    e.g., DRAW when it expects JOIN

    How should the client or server respond if an expected message doesn't
    arrive in a reasonable amount of time?