MCQ Detailed View

The Application Layer is the seventh and topmost layer of the OSI model. It serves as the interface between end users and the network services they want to access. One of the most critical tasks it performs is user authentication.

User authentication is the process where a user provides credentials—such as a username and password—to prove their identity. This step ensures that only authorized users are granted access to a service or application. Without proper authentication at the Application Layer, secure communication cannot begin.

Authentication happens through protocols and services that operate at this layer, including:

• HTTPS – used for secure web access


• SMTP – email servers authenticate users before sending emails


• FTP – requires login before file access


• Remote login services like Telnet and SSH

Other options mentioned in the question are related to lower layers:

• Frame creation – handled by the Data Link Layer


• IP addressing – performed by the Network Layer


• Signal modulation – part of the Physical Layer

Conclusion: The Application Layer is responsible for managing user-facing services like authentication, file transfer, email communication, and more. It’s a vital part of network communication where security and interaction start.