A connectionless protocol describes the communication between two network end points where a message is sent from one end point to another without a prior arrangement. At one end, the device transmits data to the other before ensuring that the device on the other end is ready to use. This describes most transmissions on the open internet. Some protocols allow for error correction by requesting a retransmission if necessary.
The internet uses a variety of connectionless protocols to function. Among the supported protocols are HTTP (hypertext transfer), IP, UDP, ICMP, IPX and TIPC. A connectionless protocol is different from a connection-oriented system. A connection-oriented system requires both devices to be able to communicate with each other.