Native VLAN Configuration and Security on Cisco Switches
Master native VLAN configuration on Cisco Catalyst switches, understand VLAN hopping attacks, and implement security best practices to protect your switched network.
VLAN
Virtual LANs and Layer 2 switching, the foundation of every campus network. Articles tagged VLAN cover fundamentals, trunking, inter-VLAN routing, EtherChannel, troubleshooting, and campus design on Cisco Catalyst switches.
Latest posts — page 4
VTP Configuration on Cisco Switches: Versions 1, 2, and 3
VTP automates VLAN propagation across switches—but a single switch with a high revision number can wipe all VLANs from your network. Learn how to configure VTPv3, manage revision numbers, and avoid the most dangerous VLAN mistake.
Configuring VLANs on Cisco Catalyst Switches
Learn how to create VLANs, assign access ports, and verify your VLAN configuration on Cisco Catalyst 9000 series switches using IOS XE 17.x.
Understanding Collision Domains
A collision domain is any segment where two devices can step on each other's frames. Here is what shrinks them, why switches help, and how it affects performance.
Local Area Network Basics: Understanding Modern LANs
Modern LANs run on high-speed switches, PoE, structured cabling, and Wi-Fi 6/7 APs. Here is a clean walkthrough of the components and how they fit together.
Configuring SVIs (Switch Virtual Interfaces) for Inter-VLAN Routing
SVIs (Switch Virtual Interfaces) are logical VLAN interfaces that enable a Layer 3 switch to route between VLANs and provide management access. Master SVI creation, IP routing enablement, and troubleshooting SVI states.
Mastering ‘Show Interface Status’ in Cisco: Top 5 Essential Tips
show interface status tells you more than up/down. Here are five tips for reading it quickly: port status, VLAN, speed/duplex, errdisable, and description use.
EtherChannel Fundamentals: Link Aggregation, PAgP vs LACP, and Load Balancing
EtherChannel presents multiple physical links as a single logical interface to the spanning tree algorithm, eliminating blocked ports and enabling true line-rate redundancy.
VLAN Naming, Ranges, and Management Best Practices on Cisco IOS XE
Deep dive into VLAN naming conventions, the difference between standard and extended range VLANs, and best practices for VLAN management and deletion on Cisco Catalyst switches.
Troubleshooting SVI Up/Down Issues on Cisco Catalyst Switches
An SVI stuck in up/down means something is wrong with the underlying VLAN — no active ports, a deleted VLAN, or STP blocking every path. Here is how to diagnose and fix every cause.
VLAN Trunking Explained: 802.1Q, Allowed Lists, and Trunk Negotiation
Learn why VLAN trunks exist, how 802.1Q tagging works, the difference between ISL and 802.1Q, and how allowed VLAN lists and trunk negotiation function in Cisco networks.