UDP applications must generally be willing to accept some loss, errors or duplication. Some applications such as [[Trivial File Transfer Protocol|TFTP]] may add rudimentary reliability mechanisms into the application layer as needed. Most often, UDP applications do not require reliability mechanisms and may even be hindered by them. [[Streaming media]], real-time multiplayer games and [[voice over IP]] (VoIP) are examples of applications that often use UDP. If an application requires a high degree of reliability, a protocol such as the [[Transmission Control Protocol]] or [[erasure code]]s may be used instead.

Lacking any congestion avoidance and control mechanisms, network-based mechanisms are required to minimize potential congestion collapse effects of uncontrolled, high rate UDP traffic loads. In other words, since UDP senders cannot detect congestion, network-based elements such as routers using packet queuing and dropping techniques will often be the only tool available to slow down excessive UDP traffic. The [[Datagram Congestion Control Protocol]] (DCCP) is being designed as a partial solution to this potential problem by adding end host TCP-friendly congestion control behavior to high-rate UDP streams such as streaming media.

While the total amount of UDP traffic found on a typical network is often in the order of only a few percent,

numerous key applications use UDP, including:

the [[Domain Name System]] (DNS),

the [[simple network management protocol]] (SNMP),

the [[Dynamic Host Configuration Protocol]] (DHCP)

and the [[Routing Information Protocol]] (RIP),