Unauthenticated VLAN Access (Guest VLAN Access)

When a PC is connected through an IP phone to a switch port that has been authorized using 802.1X or Web/MAC authentication, the IP phone is authenticated using client-based 802.1X or Web/MAC authentication and has access to secure, tagged VLANs on the port. If the PC is unauthenticated, it needs to have access to the insecure guest VLAN (unauthenticated VLAN) that has been configured for 802.1X or Web/MAC authentication. 802.1X and Web/MAC authentication normally do not allow authenticated clients (the phone) and unauthenticated clients (the PC) on the same port (unless MAC-based VLANs are enabled. See MAC-based VLANs).

Mixed port access mode allows 802.1X and Web/MAC authenticated and unauthenticated clients on the same port when the guest VLAN is the same as the port’s current untagged authenticated VLAN for authenticated clients, or when none of the authenticated clients are authorized on the untagged authenticated VLAN. Instead of having just one client per port, multiple clients can use the guest VLAN.

Authenticated clients always have precedence over guests (unauthenticated clients) if access to a client’s untagged VLAN requires removal of a guest VLAN from the port. If an authenticated client becomes authorized on its untagged VLAN as the result of initial authentication or because of an untagged packet from the client, then all 802.1X or Web/MAC authenticated guests are removed from the port and the port becomes an untagged member of the client’s untagged VLAN.