Free CCNA Course - Episode 3

Jul 17, 2024

Free CCNA Course - Episode 3

Acknowledgements

  • Sponsored by Boson Software: Known for top-notch CCNA and CCNP labs and practice exams.

Introduction

  • Discussion starts with the connectivity of modern devices (e.g., Raspberry Pi and iPhone).
  • Emphasis on the historical perspective of device communication.

Historical Context

  • 1960s Networking: Initial computers couldn't communicate; proprietary systems prevailed.
  • ARPANET (1969): First network developed by the USDOD (Department of Defense).
  • Challenges: Lack of interoperability among proprietary systems from different companies like IBM.

Evolution of Networking Models

  • Proprietary Networks: Different companies had their own networks that couldn't communicate with each other.
  • Need for Standardization: Led to the development of common networking standards.

TCP/IP Model

  • TCP/IP as the Winner: Widely adopted due to its efficiency and robustness.
  • Layered Approach: Simplifies networking by dividing it into layers:
    • Physical Layer: Ethernet cables and physical connections.
    • Data Link Layer: MAC addresses and data transfer within the same network.
    • Network Layer: IP addresses and routing packets.
    • Transport Layer: TCP/UDP protocols and port numbers.
    • Application Layer: Protocols for applications like HTTP for web browsing.

OSI Model

  • OSI Layers: Adds additional layers compared to TCP/IP model.
    • Physical, Data Link, Network (same as TCP/IP).
    • Adds Session Layer and Presentation Layer before the Application Layer.
  • Usage in Practice: Despite TCP/IP’s dominance, OSI layers (especially 1-4) are commonly referred to in practice.

Importance of OSI Model

  • Mnemonic Devices:
    • From Application to Physical: All People Seem To Need Data Processing.
    • From Physical to Application: Please Do Not Throw Sausage Pizza Away.
  • Exam Relevance: Essential for understanding and troubleshooting networks; heavily referenced in exams like CCNA.

Practice Questions

  1. Layer 2 Device:
    • Answer: Switch.
  2. Physical Layer Devices (Select two):
    • Answers: Repeaters and Hubs.

Conclusion

  • Encouragement to like, comment, and join the Discord server for further discussions and help.
  • Mention of the subsequent episode focusing on deeper analysis of OSI and TCP models.