Episode 31: Port Tagging and 802.1Q — Understanding VLAN Trunking
VLANs don’t work across multiple switches unless you understand how to carry traffic between them, and that’s where port tagging and 802.1Q come in. This episode focuses on how trunk ports are configured and how VLAN tags are added and removed as frames move across a switched network. We explain how 802.1Q tagging inserts VLAN IDs into Ethernet frames and how trunk links enable multiple VLANs to be carried on a single cable. You’ll also learn how access ports differ from trunk ports and why misconfiguring these roles can lead to traffic loss, security problems, and routing issues across segments.
We take a deep look at the concept of native VLANs and why choosing and configuring them correctly is critical to avoiding untagged traffic conflicts. Additionally, this episode discusses the dangers of dynamic trunking protocols like DTP and how disabling unnecessary features strengthens switch security. Understanding tagging and trunking isn’t just about knowing the commands—it’s about knowing how switches make decisions, how they isolate or forward VLAN traffic, and how those decisions impact real users. If you’re responsible for connecting switches in any environment, this episode gives you the clarity and confidence needed to do it right.
