One of the simplest and most common is the User Datagram Protocol, or UDP. UDP has its own header, which sits inside the data payload.

最简单和最常见的一种是用户数据报协议或 UDP。 UDP 有自己的标头，位于数据有效载荷内。

When it " absolutely, positively needs to get there" , programs use the Transmission Control Protocol, or TCP, which like UDP, rides inside the data payload of IP packets.

当它“绝对、肯定地需要到达那里”时，程序使用传输控制协议或 TCP，它与 UDP 一样，位于 IP 数据包的数据有效负载中。

However, IP is a very low level protocol – there isn't much more than a destination address in a packet's header, which is the metadata that's stored in front of the data payload.

然而，IP 是一种非常低级的协议——在数据包的标头中只有一个目标地址，这是存储在数据有效负载前面的元数据。