[Marisa Ross]

IP addresses like 192.168.100.1 are in a human-readable format, while a computer interprets the same address as a 32-bit binary number, in this case 11000000.10101000.01100100.00000001. The dots matter because the address is divided into four 8-bit bytes, or octets, each ranging from 0 to 255. 8-bit values are common in computing, and IP addressing is a great example of why it’s useful for technicians to understand how decimal values match up with binary octets. In TCP/IP, several transport layer protocols exist, each suited for different types of data and applications. The most common are Transmission Control Protocol and User Datagram Protocol, both essential for even basic networks. TCP is connection-oriented, reliable, supports error correction, flow control, and sequencing. When connecting to a remote host via its IP address, another important number is the port, or socket. Rather than identifying a host, the port number specifies a spot on the Transport layer that marks the end point of the conversation. Every TCP or UDP packet header contains a destination port, usually tied to a specific application on the remote host, and a source port, representing where the local application listens for replies.