Businesses rely on their data networks to efficiently serve customers and increase revenues. Network connectivity is extended to the homes of teleworkers and the offices of business partners through remote access and extranet VPNs. Consultants and contractors gain access to corporate network resources through the same LAN and WAN connections as regular employees. The threat of network service disruption by unauthorized sources grows as network reliability and security become more critical. Access control mechanisms enable network engineers to reduce the likelihood of intrusion of network threats such as internet worms and viruses, as well as the possibility of unauthorized people or groups gaining access to controlled or confidential information. Cisco IOS Software now offers network access control at the media access level (layer 2) through implementation of the 802.1X protocol.
802.1X is an IEEE standard for media-level access control, offering the capability to permit or deny network connectivity, control VLAN access and apply traffic policy, based on user or machine identity.