User Datagram Protocol
UDP transfers individual datagrams without its own guarantee of delivery or order. A protocol built on top must provide any required reliability.
What does UDP mean?
The User Datagram Protocol (UDP) is a transport protocol over IP that transfers individual datagrams between programs. RFC768 describes its small protocol scope and the lack of guaranteed delivery and duplicate protection. Order is not guaranteed either.
Example: sending measurements to a service
In a fictional design, a device sends measurements using UDP. The team must decide how the receiving service detects and handles missing, duplicate or delayed values. Saying “datagram sent” does not confirm receipt.
If every value were needed for billing, the transmission method would have to provide the necessary acknowledgements and retries in addition. An assumed speed advantage is not enough reason to choose it.
More extensive protocols can be built on UDP. QUIC, for example, adds its own mechanisms for reliable data streams and protected connections. The properties of such a complete solution must therefore not be equated with those of UDP alone.
Sources
Related terms
- Transmission Control ProtocolTCP provides applications with a reliable, ordered byte stream. That transport service does not confirm that a request was processed in the business workflow.
- QUICQUIC is a secure transport protocol over UDP with its own reliable streams. HTTP/3 uses QUIC; the terms refer to different protocol layers.
- IP addressAn IP address provides addressing on a network. It differs from a domain name and alone says nothing about the application reachable at that address.
- Return-PathReturn-Path records the SMTP reverse path in a header. It explains the technical route for error reports, not a person’s identity.
- Envelope-FromEnvelope-From identifies the SMTP sender for transport and error feedback. It must be distinguished from the visible sender address.
- DMARC aggregate reportA DMARC aggregate report summarises a reporting mail system’s domain checks over a period. It helps examine sending sources and misconfigurations.
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