MAC (Medium Access Control)

MAC, in networking, is the Medium Access Control sublayer of the OSI Data Link Layer (Layer 2), responsible for arbitrating access to the shared medium and framing data into addressable units. Examples include Ethernet's CSMA/CD (historical), Wi-Fi's CSMA/CA, and the cellular MAC layers in LTE and 5G NR with sophisticated scheduling.

Categories: Radio Access NetworkSecurity ControlsEncryption and Cryptography

MAC in context

The radio access network is where mobile devices attach to the operator's infrastructure. Attacks in this layer include IMSI catching, rogue base stations and downgrade attacks; defenses rest on mutual authentication, integrity-protected signaling and Open RAN supply-chain hygiene.

Security controls span signaling firewalls (SS7/Diameter/GTP screening), transport encryption (IPsec, TLS, PRINS), identity and access on OSS/BSS, and monitoring at both packet and log level. Controls are audited against GSMA FS.11/FS.19/FS.20/FS.36.

To place MAC in the wider telecom-security picture, review AP, HTTPS, RFID, MACsec, 1G and 2G — each entry cross-references back to this page so you can walk the topic in either direction.

Related terms

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