Systems Administration I: Network Switches

Switches

• More intelligent than hubs, operating on Layer 2.
• Utilize MAC addresses to make forwarding decisions in frames.
• MAC address is a unique 12-digit hexadecimal number for each network device.
• Example MAC address representation: 2C:54:91:88:C9:E3.
• Advantages include fast device detection, full duplex operation, bandwidth savings, and increased security.

Routers

• Connect multiple devices and networks, enabling data transfer between local networks and the internet.
• Operate at the Network Layer, using IP addresses to forward data packets.
• Responsible for determining the best routing path using a routing table.
• Types include:
  • Edge Routers: Connect internal networks to the internet.
  • Core Routers: Operate within the internet backbone for transmitting data packets.

Bridges

• Link different LANs to form larger network aggregations, making them appear as a single network.

Modems

• Short for modulator/demodulator, facilitating internet connection over telephone lines.
• Types:
  • External Modem: Self-contained, outside the computer.
  • Internal Modem: Installed inside the computer.
  • Wireless Modem: Sends and receives signals via radio waves.

Network Cables

• Serve as physical communication routes for data transmission between computers and network components.
• Common types include:
  • Coaxial Cable
  • Twisted Pair Cable
  • Fiber-Optic Cable

Network Servers

• Provide resources, data, and services to clients over a network.
• Manage network resources and serve client requests.
• Examples include web servers, mail servers, database servers, and print servers.

Network Software Components

• Consist of network protocols and Network Operating System (NOS).
• NOS connects and communicates between independent computers.
• Functions of NOS include controlling resource access, account management, and network monitoring.
• Examples of NOS: UNIX/Linux, MacOS, Windows Servers.

Network Protocols

• Rules for data communication among computers.
• Two popular models:
  • OSI Model: Seven layers (Physical, Data Link, Network, Transport, Session, Presentation, Application) providing a standard for network interoperability.
  • TCP/IP Model: Four layers (Physical, Network, Transport, Application), summarizing OSI features and managing files easily.

Data Encapsulation

• Process where various protocol information is added at each layer.
• Results in different Protocol Data Units (PDUs) as data moves down the protocol stack.
• Three types of addresses utilized for communication:
  • Transport layer: Protocol addresses (port numbers).
  • Network layer: Network addresses.
  • Data link layer: MAC addresses for local device identification.

Network Topologies

• Differentiation based on size, user connections, services, and management areas.
  • LAN (Local Area Network): Limited geographical area, high-speed bandwidth.
  • WAN (Wide Area Network): Spans large geographic areas, connecting multiple LANs.

Enterprise LANs and MANs

• Enterprise LANs: Use SOHO technologies on a larger scale with numerous devices.
• Metropolitan Area Network (MAN): Connects different LANs within a city, larger than LAN but smaller than WAN, covering several kilometers.

Troubleshooting Network Issues

• Involves identifying, diagnosing, and resolving network problems.
• Common issues include connectivity problems, performance lag, and security threats.
• Effective troubleshooting minimizes downtime, reduces costs, optimizes performance, and enhances security.

This quiz covers the fundamentals of network switches, focusing on their intelligence compared to hubs and their operation at layer 2 of the OSI model. It also delves into the importance of MAC addresses in frame forwarding decisions and their representation. Test your knowledge on key concepts of network administration!