The Port-based Network Access Control (PNAC) provides an authentication mechanism for any system attempting to connect to a LAN or WAN.
IEEE 802.1X is an IEEE Standard for port-based Network Access Control (PNAC). It is part of the IEEE 802.1 group of networking protocols. It provides an authentication mechanism to devices wishing to attach to a LAN or WLAN.
IEEE 802.1X defines the encapsulation of the Extensible Authentication Protocol (EAP) over wired IEEE 802 networksand over 802.11 wireless networks, which is known as "EAP over LAN" or EAPOL. EAPOL was originally specified for IEEE 802.3 Ethernet, IEEE 802.5 Token Ring, and FDDI (ANSI X3T9.5/X3T12 and ISO 9314) in 802.1X-2001, but was extended to suit other IEEE 802 LAN technologies such as IEEE 802.11 wireless in 802.1X-2004. The EAPOL was also modified for use with IEEE 802.1AE ("MACsec") and IEEE 802.1AR (Secure Device Identity, DevID) in 802.1X-2010 to support service identification and optional point to point encryption over the internal LAN segment.