Which feature is used in a push model to allow for session identification host reauthentication and session termination?

A Change of Authorization (CoA) request is a RADIUS message sent by an Authentication, Authorization, and Accounting (AAA) server to a network access device (e.g., a switch). It allows the AAA server to dynamically change a client's authorization, re-authenticate a host, or terminate a session (disconnect a user) in a 'push' manner without waiting for the client to initiate a new authentication.

Carrier-grade NAT (CGN) is a large-scale NAT implementation used by ISPs to conserve IPv4 addresses; it has no relation to session identification or reauthentication.

AAA attributes are parameters used within AAA protocols (like RADIUS or TACACS+) to convey information about the user, authentication method, or authorization policies; they are not a mechanism for dynamically pushing session changes.

An AV pair (Attribute-Value pair) is a fundamental data structure used within AAA attributes to define specific characteristics or policies, but it is not a feature for dynamic session management in a push model.