UDP Protocol Overview

Protocol Overview

UDP provides basic datagram service between two TCP/IP hosts. Whereas TCP provides a reliable stream of data, UDP sends and receives datagrams or blocks of data. UDP is used as transport for the Trivial File Transfer Protocol (TFTP), Simple Network Management Protocol (SNMP), Network Time Protocol (NTP), and others.

UDP enhances IP by providing a header that is used to route packet data to the application that binds itself to the addressed port number. UDP routes data between matching applications on TCP/IP hosts.

UDP provides an unreliable transfer of data. Unlike TCP, your application is not guaranteed that packets will find their way to their ultimate destination. For this reason, most protocols that use UDP utilize acknowledgments.

UDP is a datagram-oriented protocol. A block of data, if successfully sent and received, arrives as a block of data exactly the same size as that sent. The IP layer takes care of reassembling any packets that may have been fragmented into smaller packets during its transmission. A checksum is used for packet data and corrupted packets are discarded.

UDP system buffering provides simultaneous two-way (full-duplex) data transfer.

Typical Applications

Unlike TCP, which must establish a connection, UDP is quick to set up, easy to use, light on system resources, and simple to program. UDP also can broadcast packets to all computers on a network segment, something TCP cannot do. For these reasons UDP is often used for:

Software licensing applications
Communications with network devices like routers (that have no need to support TCP).
Applications that use packet broadcasting techniques to discover information.
Simple request/reply protocols, such as Simple Network Management Protocol and Network Time Protocol.
Applications that require maximum speed such as network gaming or chat applications.
Applications that wish to broadcast or multicast data.

In This Section

UDP Protocol Overview: An overview of the UDP protocol.
Basic Sending and Receiving of Datagrams: Demonstrates how to send and receive UDP datagrams.
Broadcasting and Multicasting Datagrams: Demonstrates how to broadcast and multicast UDP datagrams.

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Documentation version 1.1.2.0.