Computer Networks Elements

Network Elements

• Hardware devices: Computers, Printers, Phones, Routers, and Switches
• Medium: Wired, Wireless, and Satellites
• Software: Messages, Protocols, and Information that travels over the medium

Network Interface Card (NIC)

• Enables devices to directly access the network
• Types: Internal NIC (plugs into the motherboard), External NIC (Wireless and USB-based)
• MAC address: Physical address, unique, and burned on the NIC card
• IP address: Logical address, identifies each device on an IP network layer

Communication Devices

• Hub: Allows different nodes to communicate with each other at the same network (slow)
• Repeater: Regenerates the signal over the same network before it becomes too weak or corrupted
• Access Point (AP): Allows Wi-Fi devices to connect to a wired network
• Switch: Allows different nodes to communicate with each other at the same network without slowing each other
• Router: Allows different networks to communicate with each other

Network Topology

• Refers to how devices are connected (shape) and how messages flow from one device to another
• Each topology has its own advantages and disadvantages

Network Types

• Local Area Networks (LAN): Connects computers in a small geographical area (e.g., school, university campus, or office building)
  • Allows users to share files and services
  • High-speed communication
  • Under administrative control
• Wide Area Networks (WAN): Connects computers in a large geographical area (e.g., country)
  • Can contain multiple smaller networks, such as LANs or MANs
  • Very low speed
  • Under ISP administrative control
• Example of WAN: Internet

Internet

• Defined as a global mesh of interconnected networks
• No one owns the Internet
• Many organizations, ISPs, companies, and governments own pieces of Internet infrastructure
• Organizations involved: ISOC, IETF, and ICANN

Network Architectures

• Peer-to-Peer Networks: No dedicated resources, easy to work with, and all nodes are equal
• Client/Server Networks: Some nodes (servers) are dedicated to providing services to other nodes (clients)

Protocols

• Why we need protocols: To communicate efficiently, enable data to flow, and control messages
• Examples: HTTP, HTTPS, FTP, and RDP
• OSI Reference Model: Open Systems Interconnect, defined by ISO in 1983, provides universal concepts for developers
• TCP/IP: Transmission Control Protocol/Internet Protocol, open standard protocol, cross-platform, and default protocol for modern operating systems

TCP/IP vs. OSI Model

• Some protocols in TCP/IP Suite: Network Access Layer, Physical Layer, and Datalink Layer