VLANs, trunking, Spanning Tree (STP, RSTP, MSTP), EtherChannel, port security, and QoS — the technologies that turn a wiring closet full of switches into a loop-free, segmented, prioritized access layer.
Module 4 built the address plan; this module builds the Layer 2 infrastructure that plan actually runs on. Each section works a real, numbered example — a root bridge election with real path costs, an EtherChannel hash outcome, a QoS bandwidth split across priority queues — rather than describing switching concepts in the abstract.
By the end of this module you should be able to explain not just what STP, RSTP, and MSTP each do, but why an enterprise access layer typically runs several of these technologies simultaneously, each solving a different failure mode — the closing synthesis section walks through exactly that in one representative wiring-closet design.