Cisco Certified Technician Practice Test 2025 - Complete Exam Prep

The OSI (Open Systems Interconnection) reference model is best described as a seven-layer model for network architecture. Each layer of the OSI model represents a different aspect of network communication and specifies particular functions and protocols that facilitate end-to-end data transmission.

The seven layers of the OSI model are:

1. **Physical Layer** - Deals with the physical connection between devices, including cables and switches.

2. **Data Link Layer** - Provides node-to-node data transfer and handles error correction from the Physical layer.

3. **Network Layer** - Manages data routing, forwarding, and addressing.

4. **Transport Layer** - Ensures complete data transfer and error recovery.

5. **Session Layer** - Manages sessions or connections between applications.

6. **Presentation Layer** - Translates data formats and manages encryption and compression.

7. **Application Layer** - Closest to the end user, it interfaces with software applications for network services.

By understanding the purpose and function of each layer, you can better troubleshoot networking issues, implement solutions effectively, and work with protocols at different network levels. The OSI model serves as a foundational concept in networking, guiding the design and implementation of network architectures.