Layer 2 switches operate at the data link layer and are responsible for intelligently forwarding frames within a local network segment. In this episode, we explore how switches use MAC address tables to make forwarding decisions, learning source MAC addresses from incoming frames and building a dynamic table that reduces unnecessary traffic. You'll learn what happens when a switch receives a frame with an unknown destination MAC and how it uses flooding to ensure delivery without knowing exactly where the destination is located.

We also explain aging timers, table overflow, and how MAC flapping can indicate problems in your environment. This episode lays the foundation for understanding Layer 2 behavior, which is vital when diagnosing communication failures, isolating misbehaving devices, or configuring port security. If you’ve ever wondered how switches “know” where to send traffic, this episode will show you exactly how it works under the hood.