Network Topologies and Security

Network Structure

• Network topology describes the physical or logical arrangement of nodes and connections in a network. Common topologies include:
  • Bus: All devices share a single cable. Simple to install but susceptible to single points of failure.
  • Star: Devices connect to a central hub or switch. Easy to manage and troubleshoot, but the central device is a bottleneck.
  • Ring: Devices are connected in a closed loop. Data travels in one direction. Failure in any segment affects the whole network.
  • Mesh: Multiple paths exist between devices. Highly resilient but complex to configure.
  • Tree: Combines star and bus topologies, hierarchical structure.
  • Hybrid: A combination of different topologies.

Network Security

• Network security encompasses measures to protect network resources from unauthorized access, use, disruption, modification, or destruction. Key aspects include:
  • Access control: Restricting access to authorized users or devices. This can include usernames and passwords, biometrics, or multi-factor authentication.
  • Firewall: Blocking unauthorized network traffic based on predefined rules. Essential for perimeter security.
  • Intrusion detection/prevention systems (IDS/IPS): Monitor network traffic for malicious activity. IDS passively monitors, while IPS actively blocks threats.
  • Encryption: Encoding data to protect it from unauthorized decryption. Used for secure communications and data storage. Standard protocols include TLS (Transport Layer Security) and IPsec.
  • Data Loss Prevention (DLP): Prevent sensitive data from leaving the network perimeter. This can involve monitoring and blocking sensitive files.
  • User awareness training: Educate users about common cybersecurity threats and safe practices.

Types of Networks

• Networks are categorized based on geographical scope and ownership:
  • Local Area Network (LAN): Connects devices within a small geographic area like a home, office, or school. Often privately owned and managed.
  • Wide Area Network (WAN): Connects devices across extensive geographical areas, often spanning cities, countries, or even globally. Typically involves a combination of leased lines, satellite links, and internet connections. Commonly publicly available and managed by third parties.
  • Metropolitan Area Network (MAN): A network spanning a city or metropolitan area. Larger than a LAN but smaller than a WAN. May be privately or publicly owned. Examples include a city's cable network.
  • Personal Area Network (PAN): A network connecting devices owned and used by an individual, such as Bluetooth or infrared connections between a cell phone and a headset.
  • Virtual Private Network (VPN): Creates a secure, encrypted connection over a public network, like the internet. It extends a private network across a public infrastructure.
  • Wireless Local Area Network (WLAN): A LAN that utilizes wireless technologies like Wi-Fi.

Network Protocols

• Network protocols define the rules and standards for communication between devices on a network.
  • TCP/IP: A suite of protocols for internet communication. Fundamental for connecting devices worldwide.
  • HTTP/HTTPS: Protocols for web browsing. HTTPS uses encryption for secure communication.
  • FTP: Protocol for file transfer. Often used for uploading and downloading files.
  • SMTP: Protocol for sending email.
  • POP/IMAP: Protocols for receiving email.
  • DNS: Translates domain names to IP addresses. Essential for locating websites.

Network Devices

• Devices facilitate network communication:
  • Routers: Forward data packets between networks.
  • Switches: Connect devices within a local network.
  • Hubs: Broadcast data packets to all connected devices, less efficient than switches.
  • Modems: Convert digital signals to analog signals and vice-versa for communication with external networks.
  • Access points: Provide wireless network access.
  • Network Interface Cards (NICs): Provide physical connection to the network for devices.