IP, MAC, Packet and Protocols

What are they? What is their purpose?

IP addressing

Internet Protocol Address (IP) is a numerical label assigned to each device (e.g., computer, printer) participating in a computer network that uses the Internet Protocol for communication. An IP address serves two principal functions: host or network interface identification and location addressing.

MAC Addressing

A media access control address (MAC address) is a unique identifier assigned to network interfaces for communications on the physical network segment. MAC addresses are used for numerous network technologies and most network technologies, including Ethernet. Logically, MAC addresses are used in the media access control protocol sub layer of the OSI reference model.


CCSDS packet definition (The Consultative Committee for Space Data Systems)

A packet is a block of data with length that can vary between successive packets, ranging from 7 to 65,542 bytes, including the packet header. Packet sized data is transmitted via frames, which are fixed-length data blocks. The size of a frame, including frame header and control information, can range up to 2048 bytes. Packet sizes are fixed during the development phase. Because packet lengths are variable but frame lengths are fixed, packet boundaries usually do not coincide with frame boundaries.


A communications protocol is a system of digital message formats and rules for exchanging those messages in or between computing systems and in telecommunications. A protocol may have a formal description. Protocols may include signalling authentication and error detection and correction capabilities.