- Uniform Dialing Plan. See uniform dialing plan.
- User Datagram Protocol. A Transport Layer host-to-host protocol in the TCP/IP protocol suite, UDP is a connectionless protocol for datagram-oriented applications. Like the Transmission Control Protocol (TCP), UDP uses the Internet Protocol (IP) for addressing and routing purposes. Unlike TCP, UDP provides no sequencing, error control, or flow control mechanisms. An application program that uses UDP assumes full responsibility for all issues of reliability, including data loss, data integrity, packet latency, data sequencing, and loss of connectivity. UDP is used extensively in voice over Internet Protocol (VoIP) and stream-oriented multimedia applications, where compression techniques are designed to mitigate such issues over a highly shared packet network. UDP also works well where transactions are of such short duration that connection setup overhead comprises a large proportion of overall transaction traffic, as exemplified by Simple Network Management Protocol (SNMP) exchanges. The standard size of the UDP header is eight octets, as illustrated in Figure U-1. The UDP header comprises the following fields:
UDP - Computer Definition
(User Datagram Protocol) A protocol within the TCP/IP protocol suite that is used in place of TCP when a reliable delivery is not required. UDP is widely used for streaming audio and video, voice over IP (VoIP) and videoconferencing, because there is no time to retransmit erroneous or dropped packets. If UDP is used and a reliable delivery is required, packet sequence checking and error notification must be written into the applications. UDP is "connectionless" and does not use a handshake to start a session as does TCP. In a broadcast session with multiple destinations, UDP does not set up a connection with each receiver beforehand. See TCP, TCP/IP and RTP.