Networking Concepts and Technologies

Overview

• Networking involves various activities across different systems.
  • Functions include data transfer, accessing remote systems, technical support, screen sharing.
  • Traffic management ensures certain applications have higher priority.
  • System availability is crucial, requiring specialized protocols.

Content Delivery Network (CDN)

• Definition: A network of servers designed to deliver data efficiently.
• Functionality:
  • CDNs cache information geographically, reducing the time to access data.
  • Users access a nearby CDN server instead of a central server.
  • Useful for both small and large websites.

Virtual Private Network (VPN)

• Purpose: Securely connect to a remote network through encrypted data transmission.
• Components:
  • Uses a concentrator or headend device for central connection.
  • Performs high-speed encryption and decryption.
  • Can be standalone or integrated within a Next Generation firewall.
• Deployment:
  • Purpose-built appliances or software-based solutions.
  • VPN software is available on Windows, Mac OS, and Linux.

Quality of Service (QoS)

• Objective: Prioritize network traffic based on application importance.
• Methods:
  • Traffic shaping or packet shaping.
  • Manages bandwidth usage and data rates.
• Configuration:
  • Implemented in routers, switches, or firewalls.
  • Customizable application priority lists.

Time To Live (TTL)

• Role: Ensures tasks don't loop indefinitely, managing network traffic.
• Mechanism:
  • Timer-based, either on time or iterations.
  • Automatically stops or removes tasks once the timer hits zero.
• Examples:
  • Packet looping between routers.
  • Cache expiry after a certain period.

Routing Loops

• Issue: Packets circulating endlessly due to misconfigured routes.
• Resolution:
  • IP protocol uses TTL to automatically drop packets.
  • TTL decreases with each router hop, dropping packets when zero is reached.

TTL in DNS

• Function: Determines how long a DNS entry is cached.
• Configuration:
  • TTL in seconds specifies cache duration.
  • Allows administrators to update IP addresses effectively.

TTL Variations Across Protocols

• Networking (Routers): TTL based on hop count.
• DNS: TTL based on time (seconds).