QoS: the parts people skip
Marking traffic achieves nothing on its own. The queue is where the work happens.
Platform
Any platform
Vendor-neutral. The ideas here hold whatever equipment or operating system you run.
Designing a hub and spoke that tolerates outages
Every remote site will lose its link. Design for what happens during, not just after.
Vendor defaults that will hurt you
Shipping defaults are chosen so the device works out of the box, not so it is safe.
Configuration backups that are actually restorable
A directory of config files is not a recovery plan. Here is the gap.
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.
Route redistribution and the loops it creates
Two protocols feeding each other at two points will create a loop. Here is how to stop it.