The order in which bytes are sequenced in a byte-oriented network protocol is called the network byte order. The maximum size of a single unit of transmission for these protocols, the Maximum Transmission Unit (MTU), is also measured in bytes. Network programmers routinely work both with network byte ordering and MTUs.
Bytes are used not only in networking, but also for computer disks, memory, and central processing units (CPUs). In all modern network protocols, a byte contains eight bits. A few (generally obsolete) computers may use bytes of different sizes for other purposes.
The sequence of bytes in other parts of the computer may not follow the network byte order. Part of the job of the networking subsystem of a computer is to convert between the host byte order and network byte order when needed.