Core Principles of Computer Networking and Architecture

Internet and Computer Networks

• The Internet is a network of interconnected networks, linked by routers that forward data packets.
• Computer networks consist of:
  • Intermediary devices (e.g., routers, switches)
  • Network media (e.g., cables, wireless signals)
  • End devices (hosts) that serve users

Network Documentation

• Networks are represented using topology diagrams:
  • Physical topology – shows actual hardware connections
  • Logical topology – shows data flow and addressing
• Logical topology diagrams indicate:
  • Devices, media, ports, and addressing schemes

Layered Network Architecture

• Ensures interoperability between networks with different technologies.
• The TCP/IP model is the practical standard, while the OSI model is used for reference.
• Layers break down networking into smaller, manageable parts:
  • Each layer provides services to the layer above and relies on the layer below.

Network Protocols

• Protocols define communication rules at each layer.
• A protocol stack is a collection of interrelated protocols.
• Example: Similar to a shipping company using an airline to send packages.

Network Services and Layers

• Transport layer: Process-to-process communication
• Network layer: Host-to-host communication
• Data link layer: Node-to-node communication
• Physical layer: Converts data into signals for transmission

Network Addresses

• Devices and processes in a network require unique addresses:
  • Port numbers (Transport layer)
  • IP addresses (Network layer)
  • MAC addresses (Data Link layer)

Data Encapsulation and De-encapsulation

• Encapsulation:
  • Each layer adds a protocol header to the data as it moves down the stack.
  • Final data is converted into signals for transmission.
• De-encapsulation:
  • The receiving device removes headers layer by layer to extract the original data.

Network Standards

• Ensure compatibility and interoperability between different networks.
• IEEE standards apply to the Data Link layer.
• RFC (Request for Comments) defines standards for Network, Transport, and Application layers.