3.1.3 Describe how communication over networks is broken down into different layers.

Communication over networks is typically broken down into different layers to facilitate understanding, development, and troubleshooting of network protocols and systems. The most widely known and used reference model for understanding these layers is the OSI (Open Systems Interconnection) model, which consists of seven layers. Here’s a brief overview of each layer:

1. Physical Layer (Layer 1): The physical layer deals with the actual hardware components of the network, such as cables, switches, and network interfaces. It defines the physical and electrical characteristics of the transmission medium. This layer is responsible for transmitting raw binary data over the network medium.

2. Data Link Layer (Layer 2): The data link layer focuses on the reliable transmission of data frames between devices on a local network. It handles tasks like addressing, error detection, and flow control. Ethernet and Wi-Fi are examples of data link layer technologies.

3. Network Layer (Layer 3): The network layer is responsible for routing data packets between different networks or subnetworks. It deals with logical addressing, routing, and forwarding of packets. IP (Internet Protocol) is a key protocol at this layer.

4. Transport Layer (Layer 4): The transport layer ensures end-to-end communication between devices on different hosts. It manages data segmentation, error checking, and reassembly. Protocols like TCP (Transmission Control Protocol) and UDP (User Datagram Protocol) operate at this layer.

5. Session Layer (Layer 5): The session layer establishes, manages, and terminates communication sessions between two devices. It provides services like session initiation, synchronization, and data exchange coordination.

6. Presentation Layer (Layer 6): The presentation layer is responsible for data translation, encryption, and compression. It ensures that data sent by the application layer of one system can be properly interpreted by the application layer of another, regardless of differences in data formats or character sets.

7. Application Layer (Layer 7): The application layer is the top layer and is closest to the end-user. It provides network services directly to applications and end-users. This layer includes protocols like HTTP (Hypertext Transfer Protocol), FTP (File Transfer Protocol), and SMTP (Simple Mail Transfer Protocol) used for various applications like web browsing, file transfer, and email.

Note: This curriculum point requires you to have an awareness of the seven-layer OSI model, but an understanding of the functioning of each layer is not required.