+ What is Subnetting?
Subnetting is the process of dividing a large IP network into smaller, manageable networks called subnets.
+ Why do we need Subnetting?
- Efficient IP address usage
- Improved network performance
- Better security & isolation
- Reduced broadcast traffic
+ IP Address Classes (Quick Recap)
- Class A: 1.0.0.0 – 126.0.0.0 (/8)
- Class B: 128.0.0.0 – 191.255.0.0 (/16)
- Class C: 192.0.0.0 – 223.255.255.0 (/24)
+ What is CIDR?
CIDR (Classless Inter-Domain Routing) allows flexible subnet masks such as /26, /27, /28 instead of fixed classes.
+ Easy Subnetting Method (4 Steps)
- Identify the required number of hosts
- Choose subnet mask that supports hosts
- Calculate block size (256 − subnet value)
- Identify network, usable, broadcast IPs
+ Example: 192.168.1.0 /26
- Subnet Mask: 255.255.255.192
- Block Size: 64
- Subnets: 0, 64, 128, 192
- Usable Hosts per subnet: 62
+ Common Subnetting Mistakes
- Using network IP as host IP
- Using broadcast IP as host IP
- Wrong block size calculation
- Ignoring future scalability