One of the most vital control-plane concepts to master is how OSPF’s Shortest Path First (SPF) algorithm evaluates candidate links during Dijkstra’s tree calculation. It’s easy to assume that OSPF will naturally “prefer” a real multi-access segment over a loopback interface, or that it will detect conflicting subnet advertisements and throw an error. However, SPF […]
003 CCIE EI Study Notes – Why OSPF Chose the Wrong Route? Read More »
The 40-Second Rule That Can Surprise Every OSPF Student Part of my CCIE Enterprise Infrastructure Journey One of the first things we learn about OSPF Designated Router (DR) and Backup Designated Router (BDR) election is simple: the router with the highest OSPF priority wins. If there’s a tie, the router with the highest Router ID
002 CCIE EI Study Notes – Why the First 40 Seconds Decide your OSPF DR/BDR Read More »
OSPF Explained Like You’re Traveling Across the Philippines “Part of my CCIE Enterprise Infrastructure Journey.” I remember concepts much better when I can visualize them. So instead of memorizing Link State Advertisements, DR elections, and SPF calculations, I imagined traveling across the Philippines. Oddly enough… It made OSPF much easier to understand. Let’s start from
001 CCIE EI Study Notes – OSPF Explained Read More »
The Hook: Busting the Myth Let’s start with a reality check that 90% of networking articles get wrong: Distance Vector protocols aren’t the ones eating your CPU. If you are running RIP or EIGRP, your router is essentially “routing by rumor.” It takes a neighbor’s word for it, drops it in a table, and moves
The Day 1,000 OSPF Neighbors Killed ASR Router Read More »
