Jeremy's IT Lab - CCNA 200-301 Lecture 7: Layer 3 and IP Addresses

Introduction

• Free course for CCNA 200-301.
• Encouragement to subscribe, like, and utilize Anki flashcards.
• Focus of this lecture: Moving from Layer 2 to Layer 3 - understanding IP addresses.

Review of OSI Model: Layer 3 - Network Layer

• Provides connectivity between different networks.
• Uses IP addresses for logical addressing.
• Responsible for path selection between source and destination.
• Routers operate at Layer 3.

Understanding IP Addresses

• IP addresses: Logical Layer 3 addresses.
• Example Network: PCs connected via switches in the same network (192.168.1.0/24).
• Routers divide networks, creating separate LANs.
• Example setup: SW1, PC1, PC2 on 192.168.1.0/24; SW2, PC3, PC4 on 192.168.2.0/24.

IP Address Structure

• IPv4 address: 32 bits, split into 4 octets.
• Written in dotted decimal format for human readability.
• Example conversion to binary: 192.168.1.254.

Binary, Decimal, and Hexadecimal

• Decimal (Base 10), Hexadecimal (Base 16), Binary (Base 2) review.
• Conversion examples:
  • Decimal 192 to binary: 11000000.
  • Binary to Decimal: Example 10001111 is 143.
  • Decimal to Binary: Example 221 to binary (correct form not provided).

IPv4 Address Classes

• Classes A, B, C, D, E:
  • Class A: 0-126, /8 prefix.
  • Class B: 128-191, /16 prefix.
  • Class C: 192-223, /24 prefix.
  • Class D (Multicast) and E (Experimental) not focused on.

Network and Broadcast Addresses

• Network address: Host portion all 0s.
• Broadcast address: Host portion all 1s.
• First usable address: One above the network address.
• Last usable address: One below the broadcast address.

Prefix Length and Netmask

• Prefix length (e.g., /24) indicates the network portion length.
• Netmask example for Class C: 255.255.255.0.

Practice and Quiz

• Practice converting between binary and dotted decimal.
• Additional resources: Anki flashcards, packet tracer labs.

Conclusion

• Encouragement to subscribe, like, and share.
• Availability of donations and tips through Brave browser and BAT tokens.