IP Addressing

 

5.0 IP Addressing & Subnetting

Detailed IP addressing scheme using Variable Length Subnet Masking (VLSM) to efficiently allocate IP addresses for different network segments.

Network Requirements:

We have been assigned the Class C private network address 192.168.10.0/24. We need to create subnets for:

1. Public WiFi (Guest) – Requires : 30+ hosts (customer mobile devices)

2. Fixed Wired Devices – Requires : 17 hosts (12 Gaming PCs + 1 Admin PC + 1 Printer + 1 Router + 1 Switch + 1 AP)

3. Future Expansion – Room for additional devices

VLSM Calculation Steps

Step 1: Subnet for Public WiFi (Largest Requirement) Needed: 30+ hosts Formula: 2^n − 2 ≥ 30 2^5 − 2 = 30 hosts (exact, but tight) Better: 2^6 − 2 = 62 hosts (with growth room) Network: 192.168.10.0/26 Subnet Mask: 255.255.255.192 Usable Range: 192.168.10.1 – 192.168.10.62 Broadcast: 192.168.10.63

Step 2: Subnet for Fixed Wired Devices Next available IP: 192.168.10.64 Needed: 17 hosts (current) + room for expansion = 30 hosts Formula: 2^n − 2 ≥ 30 2^5 − 2 = 30 hosts ✓ Network: 192.168.10.64/27 Subnet Mask: 255.255.255.224 Usable Range: 192.168.10.65 – 192.168.10.94 Broadcast: 192.168.10.95

Step 3: Subnet for Network Infrastructure & Future Next available IP: 192.168.10.96 Needed: Small network for management Network: 192.168.10.96/28 Subnet Mask: 255.255.255.240 Usable Range: 192.168.10.97 – 192.168.10.110 Broadcast: 192.168.10.111

Final IP Allocation Table

Subnet Name	Network Address	CIDR	Subnet Mask	Usable Host Range	Broadcast Address
Public WiFi	192.168.10.0	/26	255.255.255.192	192.168.10.1  – 192.168.10.62	192.168.10.63
Fixed Wired Devices	192.168.10.64	/27	255.255.255.224	192.168.10.65 – 192.168.10.94	192.168.10.95
Infrastructure/Future	192.168.10.96	/28	255.255.255.240	192.168.10.97 – 192.168.10.110	192.168.10.111