The Wiki of Unify contains information on clients and devices, communications systems and unified communications. - Unify GmbH & Co. KG is a Trademark Licensee of Siemens AG.
802.1x is a layer-2 protocol providing authentication of an entity, it is based on the MAC-address of the entity. This entity can be any IP entity as PC, IP phone, etc.
With 802.1x it is possible to regulate the access to the network. In such a way enterpises can inhibit that unknown entities get access to the network.