1.1 Explain concepts related to the Open Systems Interconnection (OSI) reference model.

Layer 1 - Physical

Function: Responsible for transmitting raw bit streams over a physical medium (cables, wireless signals, etc).

Devices: Cables, switches (basic), repeaters, network interface cards (NICs)

Examples: Ethernet cables, fiber optics, wireless signals

Layer 2 - Data Link

Function: Provides error-free transfer of data frames between nodes on the same network. Handles physical addressing (MAC addresses) and error detection.

Devices: Switches, bridges. NICs

Examples: Ethernet frames, MAC addresses, ARP (Address Resolution Protocol).

Layer 3 - Network

Function: Handles routing of data packets between devices on different networks. Defines logical addressing (IP addresses).

Devices: Routers, layer 3 switches

Examples: IP (Internet Protocol), routers, ICMP (Internet Control Messsage Protocol), IP addressing.

Layer 4 - Transport

Functions: Ensures reliable data transfer by providing flow control, error correction, and retransmission of lost data.

Protocols: TCP (transmission control protocol), UDP (user datagram protocol)

Examples: Ports, TCP handshakes, reliability, flow control.

Layer 5 - Session

Function: Manages sessions between applications, ensuring proper communication, synchronization, and dialog control between systems.

Protocols: NetBIOS, RPC (Remote Procedure Call), SMB (Server Message Block).

Layer 6 - Presentation

Function: Translates data between the application and the transport layer, often dealing with encryption, compression, and translation between different formats.

Protocols: SSL/TLS (secure layer/transport layer security), JPEG, GIF

Examples: Encryption (HTTPS), data formatting (JSON, XML), image compression.

Layer 7 - Application

Function: Provides network services directly to the end user and handles high-level protocols for network communication.

Protocols: HTTP, FTP, DNS, SMTP, POP3, IMAP

Examples: Web browsers, email clients, file transfer applications.