Local Area Networks (LANs)

Definition & Types of Networks

• Network: Two or more computer devices connected through some media for sharing information.
• Types of Networks:
  • PAN: Personal Area Network; around an individual.
  • HAN: Home Area Network; within a home environment.
  • LAN: Local Area Network; small area, generally one building.
  • Internet: Worldwide computer network.
  • Intranet: Organization’s private network.

Network Components

• Clients and Servers:
  • Server: Powerful computer providing services to clients in the network.
    • Types of Services: File services, email, internet, web server, print server, database server.
  • Clients: Devices like desktops, laptops, tablets, smartphones using server services.
• Identifying Network Connection:
  • Extra drives in File Explorer.
  • Network activity indicator in the notification area.

Network Hardware

• Network Interface Controller (NIC):
  • Network card; built into laptops/desktops.
  • Types: Wired and wireless adapters.
• Switches:
  • Connect computers in a network for communication.
  • Example: Connecting PCs, laptops, and printers to a switch which connects to a server.
• Routers:
  • Provide wireless connectivity.

LANs

• Wired LANs: Limited to one geographical area.
• Wireless LANs (WLANs):
  • Easier to install between buildings.
  • Disadvantages: Security risks, possible performance reduction, signal loss/interference.

Communication Methods

• Cabled Networks:
  • UTP (Unshielded Twisted Pair), STP (Shielded Twisted Pair), and fiber optic cables.
  • UTP Categories (e.g., cat 5, cat 5e, cat 6).
  • Fiber optic: Uses light signals for longer distances, not affected by electrical sources.
• Wireless Networks:
  • Wireless access points and adapters.
  • Wireless typically slower than wired due to signal consistency.

Network Software

• Role: Controls communication and security in a network.
• Operating Systems: Most have built-in networking capabilities. Server editions for larger networks.

Advantages & Disadvantages of LANs

• Advantages:
  • Transfer files without physical devices.
  • Shared software and hardware.
  • Central file storage.
• Disadvantages:
  • Expensive installation and maintenance.
  • Requires network administration.
  • Wireless-specific: Security risks, performance issues, signal interference.

Network Topologies

• Bus Topology: One main cable connects all computers.
• Star Topology: Each computer connects to a central switch.
• Ring Topology: Computers connected in a circular fashion; data travels one way.
• Mesh Topology: Every node connects directly to every other node; high reliability but complex.

Basic Network Security

• Goals: Prevent unauthorized access and network misuse.
• Measures:
  • Restrict access to confidential files.
  • Use usernames and passwords for network access.
  • Password guidelines: At least 8 characters, mix of letters, numbers, special characters, change regularly.

Ethical Use of Networks

• Acceptable Use Policy (AUP):
  • Defines rights and responsibilities of users.
  • Includes rules on data access, usage limits, and restrictions on installing hardware/software.