MACalikerros

MACalikerros is a Finnish term referring to the Media Access Control layer within the data link layer of computer networking. In the OSI model it corresponds to Layer 2 and is responsible for controlling access to the physical transmission medium and for formatting data into frames for transmission.

The MAC layer provides addressing, frame delimitation, and error detection at the frame level, typically through destination and source MAC addresses and a frame check sequence. It governs how devices access a shared medium, handling sequencing, collision avoidance or resolution, and timing in various technologies.

In practice, the MAC layer is closely tied to the physical layer and is implemented in network interface hardware and drivers. It interfaces with the LLC sublayer above it, which handles multiplexing of different network layer protocols. Different technologies implement distinct MAC protocols: Ethernet (IEEE 802.3), Wi-Fi (IEEE 802.11), and others have their own frame formats and access methods (for example CSMA/CD in older Ethernet, CSMA/CA in Wi-Fi).

Because the MAC layer is technology-specific, the term MACalikerros is often used in Finnish-language texts to discuss generic properties of the MAC layer or in comparative analyses of different media access methods. However, in international literature the term MAC layer or Data Link Layer MAC sublayer is standard.

Understanding the MAC layer is essential for network design, performance analysis, and security considerations, including addressing schemes, broadcast domains, and vulnerability to spoofing and replay attacks at the data-link level.

See also: OSI model, Data link layer, MAC address, IEEE 802 standards, Ethernet, Wi-Fi, CSMA/CD, CSMA/CA, LLC.