&gt; That said, most protocol implementations that I&#x27;m aware of over UDP have one or more of &quot;retry&#x2F;order checking&#x2F;etc&quot; on top of them.<p>But it&#x27;s a common false belief that it would be &quot;reimplementing TCP&quot;. Some guarantees of reliability are required for most practical applications but TCP&#x27;s &quot;in-order stream of bytes&quot; isn&#x27;t suitable for everything.<p>For any kind of real time data, when packet loss occurs, TCP will re-send data that may already be outdated, and causing later packets to arrive even later. In real time uses, TCP makes any networking problems worse.<p>It&#x27;s also worth noting that under ideal conditions (ie. no packet loss), TCP and UDP behave almost identically (after startup, that is). The issues only appear when you&#x27;re working in less than ideal conditions and are worse the longer the physical distances are.