Because UDP is not a connection-based protocol such as TCP, you do not need to establish a connection with a destination before you send or receive data. Instead, you specify the destination for the data when you send each datagram. Operating systems do not report transmission errors.
Use the UDP Open function to open a UDP socket on a port. The number of simultaneously open UDP ports depends on the operating system. The UDP Open function returns a network connection refnum that uniquely identifies the UDP socket. Use this connection refnum to refer to this socket in subsequent VI calls.