Introduction to Subnetting and Classful Addressing
📌 The session aims to teach learners how to understand subnetting and the procedure to subnet a network.
🧐 Classful addressing (Classes A, B, C) wastes IP addresses (e.g., Class C allows 254 hosts, often more than needed for smaller requirements like 10 computers).
🌐 Subnetting allows migrating from the wasteful classful world to a classless world by creating logical subdivisions of an IP network.

Concept of Subnets and Addressing
🖥️ Computers within the same subnet are addressed with an identical most significant bit group in their IP addresses, determining if they are on the same local network.
🏠 Without subnetting, a Class C network like 192.168.14.0 uses the default mask 255.255.255.0, treating all addresses (e.g., .1 to .254) as one network.
🔗 Creating two logical subnets from 192.168.14.0/24 involves splitting the 256 addresses into two halves (e.g., .0 to .127 and .128 to .255).

Communication Requirements in Subnetted Networks
↔️ Devices within the same subnet can communicate using a switch.
🔄 Devices in different subnets (e.g., 192.168.14.1 and 192.168.14.129 after splitting) require a router for inter-subnet communication.
🚫 Using the default subnet mask prevents logical partitioning; a new subnet mask is necessary to define the boundaries of the new logical networks.

The Five-Step Subnetting Procedure
1️⃣ Identify the IP class and note the default subnet mask.
2️⃣ Convert the default subnet mask into binary.
3️⃣ Determine the required number of hosts per subnet to find the subnet generator and the correct octet position.
4️⃣ Generate the new subnet mask to logically partition the network.
5️⃣ Use the subnet generator to create the network ranges (subnets) in the appropriate octet position.

Key Points & Insights
➡️ Subnetting solves the issue of IP address wastage inherent in classful addressing.
➡️ Communication between hosts in different logical subnets mandates the use of a router, whereas same-subnet communication relies on a switch.
➡️ The subnet mask is crucial as it dictates whether two devices belong to the same network or require routing.

📸 Video summarized with SummaryTube.com on Nov 21, 2025, 13:40 UTC