什么时候使用UDP代替TCP？ [关闭]

比眉伴天荒 2022-11-26 14:57 129阅读 0赞

本文翻译自：[When is it appropriate to use UDP instead of TCP? \[closed\]][When is it appropriate to use UDP instead of TCP_ _closed]

*Since TCP guarantees packet delivery and thus can be considered "reliable", whereas UDP doesn't guarantee anything and packets can be lost.* **由于TCP保证了数据包的传递，因此可以被认为是“可靠的”，而UDP不保证任何内容，因此数据包可能会丢失。** *What would be the advantage of transmitting data using UDP in an application rather than over a TCP stream?* **在应用程序中而不是通过TCP流使用UDP传输数据的优势是什么？** *In what kind of situations would UDP be the better choice, and why?* **在哪种情况下，UDP是更好的选择，为什么？**

*I'm assuming that UDP is faster since it doesn't have the overhead of creating and maintaining a stream, but wouldn't that be irrelevant if some data never reaches its destination?* **我假设UDP更快，因为它没有创建和维护流的开销，但是如果某些数据永远不会到达目的地，那不是无关紧要的吗？**

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### \#1楼 ###

参考：[https://stackoom.com/question/4C4E/什么时候使用UDP代替TCP-关闭][https_stackoom.com_question_4C4E_UDP_TCP-]

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### \#2楼 ###

*We know that the UDP is a connection-less protocol, so it is* **我们知道UDP是一种无连接协议，因此**

1.  *suitable for process that require simple request-response communication.* **适用于需要简单的请求-响应通信的过程。**
2.  *suitable for process which has internal flow ,error control* **适用于内部流程，错误控制的过程**
3.  *suitable for broad casting and multicasting* **适用于广泛的广播和组播**

*Specific examples:* **具体示例：**

*  *used in SNMP* **在SNMP中使用**
 *  *used for some route updating protocols such as RIP* **用于某些路由更新协议，例如RIP**

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### \#3楼 ###

视频流是使用UDP的完美示例。

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### \#4楼 ###

UDP确实具有较少的开销，并且非常适合执行诸如流传输实时数据（如音频或视频）之类的事情，或者在任何情况下如果数据丢失都可以。

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### \#5楼 ###

*If a [TCP][] packet is lost, it will be resent.* **如果[TCP][]数据包丢失，它将被重新发送。** *That is not handy for applications that rely on data being handled in a specific order in real time.* **对于依赖于以特定顺序实时处理数据的应用程序而言，这并不方便。**

*Examples include video streaming and especially [VoIP][] (eg [Skype][] ).* **示例包括视频流，尤其是[VoIP][] （例如[Skype][] ）。** *In those instances, however, a dropped packet is not such a big deal: our senses aren't perfect, so we may not even notice.* **但是，在这些情况下，丢包并不是什么大问题：我们的感觉并不完美，因此我们甚至可能不会注意到。** *That is why these types of applications use [UDP][] instead of TCP.* **这就是为什么这些类型的应用程序使用[UDP][]而不是TCP。**

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### \#6楼 ###

*The "unreliability" of UDP is a formalism.* **UDP的“不可靠性”是形式主义。** *Transmission isn't absolutely guaranteed.* **传输不是绝对保证的。** *As a practical matter, they almost always get through.* **实际上，它们几乎总是能够通过。** *They just aren't acknowledged and retried after a timeout.* **超时后，它们不会被确认并重试。**

*The overhead in negotiating for a TCP socket and handshaking the TCP packets is huge.* **协商TCP套接字和握手TCP数据包的开销很大。** *Really huge.* **真的很大。** *There is no appreciable UDP overhead.* **没有明显的UDP开销。**

*Most importantly, you can easily supplement UDP with some reliable delivery hand-shaking that's less overhead than TCP.* **最重要的是，您可以通过一些可靠的交付握手协议轻松补充UDP，而这些握手协议的开销要比TCP少。** *Read this: [http://en.wikipedia.org/wiki/Reliable\_User\_Datagram\_Protocol][http_en.wikipedia.org_wiki_Reliable_User_Datagram_Protocol]* **阅读此内容： [http][http_en.wikipedia.org_wiki_Reliable_User_Datagram_Protocol] : [//en.wikipedia.org/wiki/Reliable\_User\_Datagram\_Protocol][http_en.wikipedia.org_wiki_Reliable_User_Datagram_Protocol]**

*UDP is useful for broadcasting information in a publish-subscribe kind of application.* **UDP对于在发布-订阅类型的应用程序中广播信息很有用。** *IIRC, TIBCO makes heavy use of UDP for notification of state change.* **IIRC，TIBCO大量使用UDP来通知状态更改。**

*Any other kind of one-way "significant event" or "logging" activity can be handled nicely with UDP packets.* **UDP数据包可以很好地处理任何其他类型的单向“重大事件”或“日志记录”活动。** *You want to send notification without constructing an entire socket.* **您要发送通知而无需构造整个套接字。** *You don't expect any response from the various listeners.* **您不会期望各种听众有任何回应。**

*System "heartbeat" or "I'm alive" messages are a good choice, also.* **系统“心跳”或“我还活着”消息也是一个不错的选择。** *Missing one isn't a crisis.* **错过一个不是危机。** *Missing half a dozen (in a row) is.* **（连续）丢失六打。**

[When is it appropriate to use UDP instead of TCP_ _closed]: https://oldbug.net/q/4C4E/When-is-it-appropriate-to-use-UDP-instead-of-TCP-closed
[https_stackoom.com_question_4C4E_UDP_TCP-]: https://stackoom.com/question/4C4E/%E4%BB%80%E4%B9%88%E6%97%B6%E5%80%99%E4%BD%BF%E7%94%A8UDP%E4%BB%A3%E6%9B%BFTCP-%E5%85%B3%E9%97%AD
[TCP]: http://en.wikipedia.org/wiki/Transmission_Control_Protocol
[VoIP]: http://en.wikipedia.org/wiki/Voice_over_Internet_Protocol
[Skype]: http://www.skype.com
[UDP]: http://en.wikipedia.org/wiki/User_Datagram_Protocol
[http_en.wikipedia.org_wiki_Reliable_User_Datagram_Protocol]: http://en.wikipedia.org/wiki/Reliable_User_Datagram_Protocol