Which protocol does Cisco ISE primarily use for communication in a network environment?

Cisco Identity Services Engine (ISE) primarily uses RADIUS (Remote Authentication Dial-In User Service) for communication within a network environment. RADIUS is essential for network access control, enabling Cisco ISE to provide authentication, authorization, and accounting services for users attempting to connect to the network.

RADIUS facilitates secure communication between the client and the server, which is crucial for managing policies related to user identity, access control, and network resource management. By using RADIUS, Cisco ISE can effectively handle requests from various endpoints and enforce security policies based on user roles and device types.

The other protocols listed, while having their own unique uses, do not serve as the primary communication protocol for the functions that Cisco ISE performs. TACACS+ is more focused on device administration control rather than user access control in a network context, HTTPS is utilized for secure web communications but does not directly pertain to authentication processes, and FTP is oriented towards file transfer, lacking the security and control mechanisms necessary for identity management.