QoS: the parts people skip
Marking traffic achieves nothing on its own. The queue is where the work happens.
Platform
Cisco IOS / IOS-XE
Cisco routers and switches running IOS or IOS-XE. Much of it carries to NX-OS.
Vendor defaults that will hurt you
Shipping defaults are chosen so the device works out of the box, not so it is safe.
Junos commit and rollback: the feature worth envying
Configuration as a transaction changes how confidently you can work.
RouterOS for people who learned on IOS
The concepts transfer. The assumptions do not, and a few of them will bite.
Three vendors, one idea, three dialects
Once you see the shared model underneath, moving between vendors stops being retraining.
Convergence: measuring what your network actually does
Everyone claims sub-second failover. Very few have measured it.
Default routes and the black holes they create
A default route means "send it here and hope". Sometimes hope is misplaced.
VRFs: separation without separate hardware
One router, several routing tables that cannot see each other. Where that helps and what it costs.
Static routes: when they are the right answer
Dynamic routing is not automatically better. Sometimes the static route is the professional choice.
Administrative distance, explained properly
It is not a metric and it never leaves the router. That is the whole idea.