The extensible authentication protocol (EAP) is an authentication framework that supports multiple authentication mechanisms between a supplicant and an authentication server in a data communication network. EAP can be used as a basic tool for enabling user authentication and distribution of session keys in a data communication network. Since there are several EAP methods, the application designer should select the optimal EAP method among them. This revision to Recommendation ITU-T X.1034 describes a framework for EAP-based authentication and key management for securing the lower layer in a communication network. It provides guidance on the selection of EAP methods and describes the mechanism for key management for the lower layer of a data communication network. The framework described in this recommendation can be applied to protect data communication networks with either wireless access network or wired access network with a shared medium.