Skip the Day 0 wizard and configure the Cisco Catalyst 9800CL via CLI, including management interface, trustpoint, AP join, GUI access, and bootstrap commands.
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.
Learn how to create VLANs, assign access ports, and verify your VLAN configuration on Cisco Catalyst 9000 series switches using IOS XE 17.x.
Cisco Modeling Labs 2.8 is now free, with a tier that lets you run routers, switches, and firewalls on your laptop. Here is what it unlocks for lab work and certs.
CML 2.8 brings a free tier, new images, and updated tooling for network simulation. Here is what is new, who benefits, and how to get the most out of the release.
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.
A working Cisco ASA cheat sheet: show version, write memory, failover, ACLs, NAT, and the troubleshooting commands you actually reach for under pressure.
OSPF is a link-state routing protocol that builds an LSDB, runs Dijkstra, and converges fast. Here is what problem it solves, how it works, and where it fits.
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.
IPv4 gives every networked device a 32-bit address split across classes and subnets. Here is how IPv4 addressing works, why it still runs the internet, and its limits.
The OSI model's seven layers explain how data moves from application to wire. Here is each layer, the key protocols, and how to use the model for troubleshooting.
Straight-through cables connect PC to switch or router; crossover cables connect like to like. Here is the pinout, color code, and when Auto-MDIX makes it moot.
