Articles
Access and trunk ports: one VLAN on a port, or many over one link
What an access port and a trunk port each carry, how untagged and IEEE 802.1Q-tagged traffic differ on a trunk, and how to configure and verify both on Cisco IOS XE.
Network switching
Directly assigned
Articles
Link aggregation and LACP: making several links look like one
How link aggregation bundles parallel links into one logical interface, what LACP negotiates before the bundle is used, and why one flow still moves at one link speed.
Articles
The native VLAN: what it is and why the design choice matters
What the native VLAN means on an 802.1Q trunk, how untagged traffic is classified, and why the choice affects spanning tree and segmentation.
Articles
PoE and physical links: power, speed and duplex at the port
How a switch port powers a device over the cable (PoE) and how both ends agree on speed and duplex — and the Cisco IOS-XE commands used to inspect and control them.
Articles
STP and loop prevention: keeping a Layer 2 network loop-free
Why a Layer 2 loop becomes a broadcast storm, how STP elects a root and blocks the ports that would close a loop, and how to configure and verify it on Cisco IOS-XE.
Articles
Switching and MAC learning in operation: reading and controlling the MAC address table
How a Cisco IOS-XE switch stores what it has learned, how to read, populate, age and clear the MAC address table, and what its entries actually tell you about a Layer 2 network.
Articles
VLANs and 802.1Q tagging: how one link carries many networks
How IEEE 802.1Q lets a single link carry many VLANs — the 4-byte tag, access and trunk ports, and the native VLAN.