UDP vs TCP

UDP

UDP messages are sent without any error checks, so if they are lost you would not know. Qlab's implementation means that, after 1 minute without receiving a message, it stops updating the originator of the message. Therefore, if connecting using UDP, you must enable a "Thump", or heartbeat, message. This is set to send every 20 seconds, so that if a message is lost, you do not lose your connection.

TCP

TCP messages are a constant, confirmed connection. They also confirm that a message has been delivered. They require slightly more CPU, but ensure you remain connected to Qlab, and will cause an error if the connection is dropped.