computer networking

Sample example

1. Network Communication Protocols
   Key protocols:

• TCP – Reliable, connection-oriented (e.g., web, email)
• UDP – Fast, connectionless (e.g., video, DNS)
• HTTP/HTTPS – Web data transfer
• FTP/SFTP – File transfer
• DNS – Domain-to-IP resolution
• SMTP/POP3/IMAP – Email handling
• ICMP – Network diagnostics (ping)

1. TCP/IP vs OSI Model

• TCP/IP (4 layers):
  1. Link (Physical + Data Link)
  2. Internet (IP)
  3. Transport (TCP/UDP)
  4. Application (HTTP, FTP, etc.)
• OSI (7 layers):
  1. Physical → 2. Data Link → 3. Network → 4. Transport → 5. Session → 6. Presentation → 7. Application
     TCP/IP is practical; OSI is theoretical reference.

1. IP Addressing
   Unique identifier (IPv4: 32-bit, e.g., 192.168.1.1; IPv6: 128-bit, e.g., 2001:db8::1).
   Used to route data across networks. Includes subnet masks (network/host division) and CIDR notation.

2. Network Insecurity & CIA Triangle
   Threats: Eavesdropping, DoS, MITM, malware, spoofing.
   CIA Enforcement:

• Confidentiality: Encryption (TLS, VPN)
• Integrity: Hashes, digital signatures
• Availability: Firewalls, DDoS protection, redundancy

Security = CIA triad applied via tech + policy.