Native VLAN Explained: Untagged Traffic and VLAN Hopping
The native VLAN is one of those concepts that seems trivial - it is "the untagged VLAN on a trunk&
4 min read
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.
36 posts
VTP (VLAN Trunking Protocol): v1, v2, v3 and Why It's Dangerous
How VTP propagates VLANs across a domain, the three modes, the revision-number disaster, v1/v2/v3 differences, and why many engineers disable it.
5 min read
Per-VLAN Spanning Tree (PVST+ and Rapid-PVST+) Explained
Per-VLAN Spanning Tree explained: PVST+ vs Rapid-PVST+, the sys-id-ext Bridge ID trick, per-VLAN root placement for uplink load balancing, and when to move to MSTP.
5 min read
VLAN vs VXLAN: The L2 Overlay, Demystified
VLAN vs VXLAN explained: a VLAN tags L2 segments, VXLAN encapsulates them across L3. The 4,094 limit, VTEPs, BGP EVPN, and when you actually need VXLAN.
4 min read
STP and EtherChannel: When They Collide and Who Wins
How EtherChannel hides bundled links from STP, the bundling protocols (LACP, PAgP, on), the dangerous failure modes, and why LACP active on both sides is the only safe configuration.
5 min read
Inter-VLAN Routing: SVI vs Router-on-a-Stick (with Real IOS XE Config)
The two ways to route between VLANs on Cisco: SVIs on an L3 switch and router-on-a-stick. Real IOS XE config for both, the performance gap, and the gotchas.
5 min read