Extensible Authentication Protocol
Windows Vista Service Details
The Exensible Authentication Protocol (EAP) is used for PPP connection authentication. If you need VPN or dial-up access then you will probably need this service. Wireless Access Points (WAPs) use this for authentication as well, so if you use a wireless card, you will want to leave this alone as well
The Extensible Authentication Protocol (EAP) service provides network authentication for 802.1x wired and wireless, Virtual Private Network (VPN), and Network Access Protection (NAP). It also provides APIs used by network access clients, including wireless and VPN clients, during the authentication process. If you disable the service, the PC cannot access networks that require EAP authentication.
Consequences of Stopping:
All services listed in 'Required For' will be unable to function
Wired AutoConfig, WLAN AutoConfig