Journal Entry: July 9, 2026

Progress Report: Demystifying the Network Layer

Today was a relatively quiet day on the project front, so I redirected my focus toward my IT Support Specialist certification course. I dove deep into core networking fundamentals, specifically focusing on Layer 3 of the OSI model: The Network Layer.

While the modules were bite-sized, they covered the critical mechanisms that allow data to route across disparate networks globally. Here is a breakdown of the core topics I tackled today:

• The Network Layer & IPv4 Datagrams: Explored how data is encapsulated into packets at the network layer, including the structure of an IPv4 header and how routers use this information to direct traffic.
• IP Addressing & Classes: Reviewed the architecture of IPv4 addresses, breaking down how the 32-bit address space is traditionally divided into Classes A, B, and C to separate network IDs from host IDs.
• Address Resolution Protocol (ARP): Looked at how devices map a known network-layer IP address to a physical, local link-layer MAC address using ARP tables and broadcasts.
• Subnetting: Began cracking open the complexities of subnetting—the process of splitting a single large network into smaller, more manageable sub-networks to optimize traffic and security.

To wrap up the session, I took the Network Layer Knowledge Assessment and walked away with a clean 100% score.

Tomorrow, I'll be diving deeper into the math and mechanics behind subnet masks. One packet at a time.