Which layer is NOT part of the Transport Layer Security (TLS) protocol?

The Data Link Layer is not part of the Transport Layer Security (TLS) protocol. TLS functions at a higher level in the networking model, specifically above the Transport Layer and below the Application Layer.

The TLS protocol incorporates both the TLS Record Protocol and the TLS Handshake Protocol. The Record Protocol is responsible for encapsulating and securing data, while the Handshake Protocol is essential for establishing a secure connection, negotiating encryption keys, and authenticating the parties involved in the communication.

In contrast, the Data Link Layer is part of the OSI model, which deals with node-to-node data transfer and the physical addressing of devices on a specific segment of a network, rather than securing data in transit.