Free CCNA | Subnetting (Part 2) | Day 14 | CCNA 200-301 Complete Course

Introduction

This tutorial continues the exploration of subnetting, focusing on Class B networks as part of the free CCNA 200-301 complete course by Jeremy's IT Lab. Understanding subnetting is crucial for network design and management, making it an essential topic for CCNA certification.

Step 1: Review Subnetting Basics

• Familiarize yourself with the subnetting process, especially if you're coming from Class C networks.
• Understand the concept of subnet masks and how they define the network and host portions of an IP address.
• Remember that subnetting allows you to divide a larger network into smaller, more manageable segments.

Step 2: Apply a Subnetting Trick

• Use the Subnetting Trick to simplify calculations:
  • Memorize the common subnet masks and their corresponding CIDR notation:
    • 255.0.0.0 ( /8 )
    • 255.255.0.0 ( /16 )
    • 255.255.255.0 ( /24 )
  • This will make it easier to determine the number of subnets and hosts.

Step 3: Practice Identifying Subnets

• Work on identifying the subnet (network address) for given IP addresses.
• Utilize the following steps:
  1. Determine the class of the IP address (Class A, B, or C).
  2. Apply the appropriate subnet mask.
  3. Calculate the network address by performing a bitwise AND operation between the IP address and subnet mask.

Step 4: Calculate the Number of Hosts per Subnet

• For Class C networks:
  • Use the formula:
    • Number of hosts = 2^(32 - subnet bits) - 2
  • Remember to subtract 2 for the network and broadcast addresses.

Step 5: Subnetting Class B Networks

• Identify the unique challenges of subnetting Class B networks:
  • Class B networks have a default subnet mask of 255.255.0.0 ( /16 ).
  • You can borrow bits from the host portion to create additional subnets.
• Follow these steps:
  1. Decide how many subnets you need.
  2. Calculate the new subnet mask by determining how many bits to borrow.
  3. Calculate the number of hosts per subnet using the formula from Step 4.

Step 6: Determine Appropriate Prefix Length

• Assess the requirements of your network to choose an appropriate prefix length:
  • Consider factors like the number of required subnets and hosts.
  • Use the following guidelines:
    • More borrowed bits = more subnets but fewer hosts per subnet.
    • Balance the needs of your network when choosing the prefix.

Step 7: Engage with Quizzes

• Test your knowledge with quizzes provided in the video:
  • Quizzes reinforce learning and retention.
  • Answers are available in the subsequent video for self-assessment.

Conclusion

This tutorial outlined the key concepts of subnetting Class B networks, including identification of subnets, calculating the number of hosts, and determining appropriate prefix lengths. Practice these skills through hands-on exercises and quizzes to solidify your understanding. As you continue your CCNA journey, keep reviewing these concepts to ensure mastery.