OSI Model and TCP/IP Protocol

OSI Model

• 7 layers: Physical (1), Data Link (2), Network (3), Transport (4), Session (5), Presentation (6), Application (7)
• Each layer communicates with its peer layer on other devices through a standardized interface
• Layers 1-3: Media, packets, and routing
• Layers 4-7: Data, segments, and user interface

TCP/IP Protocol

• 4-layer model: Network Access (1-2), Internet (3), Transport (4), Application (5-7)
• Corresponds to OSI layers: 1-2, 3, 4, 5-7
• TCP/IP is the protocol suite used on the internet

Network Topologies

• Physical:
  • Bus: Single cable connecting all devices
  • Star: Central device connecting multiple devices
  • Ring: Devices connected in a circular configuration
  • Mesh: Each device connected to every other device
• Logical:
  • Point-to-Point: Two devices connected directly
  • Point-to-Multipoint: One device connected to multiple devices

Switching Fundamentals

• Switching: Forwarding data between devices on a network
• Switch types:
  • Unmanaged: Simple, plug-and-play devices
  • Managed: Configurable, with advanced features
  • Layer 2: Forwarding based on MAC addresses
  • Layer 3: Forwarding based on IP addresses

IPv4

• 32-bit address: 4 octets (8-bit) separated by dots
• Address types:
  • Unicast: One device
  • Multicast: Multiple devices
  • Broadcast: All devices on a network
• IPv4 address exhaustion: Limited address space, leading to the development of IPv6

IPv6

• 128-bit address: 8 groups of 4 hexadecimal digits separated by colons
• Address types:
  • Unicast: One device
  • Multicast: Multiple devices
  • Anycast: Multiple devices, with the closest one responding
• Features:
  • Larger address space
  • Improved security
  • Simplified header format

Spanning Tree Protocol (STP)

• Prevents network loops and broadcast storms
• Elects a root bridge and calculates the shortest path to it
• Blocks or forwards traffic based on the calculated path

Wireless LAN (WLAN)

• Wireless networking: Devices connect using radio waves
• WLAN standards:
  • IEEE 802.11 (Wi-Fi)
  • IEEE 802.15 (Bluetooth)
  • IEEE 802.16 (WiMAX)
• WLAN components:
  • Access Point (AP): Connects to a wired network
  • Station (STA): Wireless device connecting to the AP

Transport Layer

• Responsible for data segmentation and reassembly
• Protocols:
  • TCP (Transmission Control Protocol): Reliable, connection-oriented
  • UDP (User Datagram Protocol): Best-effort, connectionless
• Features:
  • Multiplexing: Multiple sessions over a single connection
  • Windowing: Flow control and error detection

OSI Model

• 7 layers allow for communication between devices through standardized interfaces
• Layers 1-3 focus on media, packets, and routing
• Layers 4-7 focus on data, segments, and user interface

TCP/IP Protocol

• 4-layer model aligns with OSI layers 1-2, 3, 4, and 5-7
• TCP/IP is the primary protocol suite used on the internet

Network Topologies

Physical Topologies

• Bus: single cable connects all devices
• Star: central device connects multiple devices
• Ring: devices connected in a circular configuration
• Mesh: each device connected to every other device

Logical Topologies

• Point-to-Point: two devices connected directly
• Point-to-Multipoint: one device connected to multiple devices

Switching Fundamentals

• Switching: forwarding data between devices on a network
• Unmanaged switches: simple, plug-and-play devices
• Managed switches: configurable, with advanced features
• Layer 2 switches: forward based on MAC addresses
• Layer 3 switches: forward based on IP addresses

IPv4

• 32-bit address: 4 octets separated by dots
• Unicast addresses: one device
• Multicast addresses: multiple devices
• Broadcast addresses: all devices on a network
• IPv4 address exhaustion led to the development of IPv6

IPv6

• 128-bit address: 8 groups of 4 hexadecimal digits separated by colons
• Unicast addresses: one device
• Multicast addresses: multiple devices
• Anycast addresses: multiple devices, with the closest one responding
• Features: larger address space, improved security, and simplified header format

Spanning Tree Protocol (STP)

• Prevents network loops and broadcast storms
• Elects a root bridge and calculates the shortest path to it
• Blocks or forwards traffic based on the calculated path

Wireless LAN (WLAN)

• Wireless networking: devices connect using radio waves
• WLAN standards: IEEE 802.11 (Wi-Fi), IEEE 802.15 (Bluetooth), and IEEE 802.16 (WiMAX)
• Access Point (AP): connects to a wired network
• Station (STA): wireless device connecting to the AP

Transport Layer

• Responsible for data segmentation and reassembly
• TCP: reliable, connection-oriented protocol
• UDP: best-effort, connectionless protocol
• Multiplexing: multiple sessions over a single connection
• Windowing: flow control and error detection

OSI Model

• The OSI model consists of 7 layers, which are: Physical (1), Data Link (2), Network (3), Transport (4), Session (5), Presentation (6), and Application (7)
• Each layer communicates with its peer layer on other devices through a standardized interface
• The lower layers (1-3) focus on media, packets, and routing, while the upper layers (4-7) focus on data, segments, and user interface

TCP/IP Protocol

• The TCP/IP protocol is a 4-layer model, which consists of Network Access (1-2), Internet (3), Transport (4), and Application (5-7)
• TCP/IP corresponds to the OSI layers 1-2, 3, 4, and 5-7
• TCP/IP is the protocol suite used on the internet

Network Topologies

• Physical network topologies include:
  • Bus: A single cable connecting all devices
  • Star: A central device connecting multiple devices
  • Ring: Devices connected in a circular configuration
  • Mesh: Each device connected to every other device
• Logical network topologies include:
  • Point-to-Point: Two devices connected directly
  • Point-to-Multipoint: One device connected to multiple devices

Switching Fundamentals

• Switching is the process of forwarding data between devices on a network
• Switch types include:
  • Unmanaged: Simple, plug-and-play devices
  • Managed: Configurable, with advanced features
  • Layer 2: Forwarding based on MAC addresses
  • Layer 3: Forwarding based on IP addresses

IPv4

• IPv4 addresses are 32-bit, consisting of 4 octets (8-bit) separated by dots
• IPv4 address types include:
  • Unicast: One device
  • Multicast: Multiple devices
  • Broadcast: All devices on a network
• IPv4 has a limited address space, leading to the development of IPv6

IPv6

• IPv6 addresses are 128-bit, consisting of 8 groups of 4 hexadecimal digits separated by colons
• IPv6 address types include:
  • Unicast: One device
  • Multicast: Multiple devices
  • Anycast: Multiple devices, with the closest one responding
• IPv6 features include:
  • Larger address space
  • Improved security
  • Simplified header format

Spanning Tree Protocol (STP)

• STP prevents network loops and broadcast storms by electing a root bridge and calculating the shortest path to it
• STP blocks or forwards traffic based on the calculated path

Wireless LAN (WLAN)

• WLAN is a wireless networking technology, where devices connect using radio waves
• WLAN standards include:
  • IEEE 802.11 (Wi-Fi)
  • IEEE 802.15 (Bluetooth)
  • IEEE 802.16 (WiMAX)
• WLAN components include:
  • Access Point (AP): Connects to a wired network
  • Station (STA): Wireless device connecting to the AP

Transport Layer

• The transport layer is responsible for data segmentation and reassembly
• Protocols used in the transport layer include:
  • TCP (Transmission Control Protocol): Reliable, connection-oriented
  • UDP (User Datagram Protocol): Best-effort, connectionless
• Features of the transport layer include:
  • Multiplexing: Multiple sessions over a single connection
  • Windowing: Flow control and error detection