Root bridge election, BPDU exchange, and the spanning tree algorithm are the core mechanics of STP. This article walks through the entire process with configuration and show command output.
STP timers control convergence speed, BPDU frequency, and failure detection. Understanding how hello, forward delay, and max age interact is essential to designing stable networks and troubleshooting convergence issues.
STP port states control when a port begins forwarding traffic. The five states and their transitions define convergence time. Understanding state machine timers is essential to designing networks that recover quickly from failures.
STP port roles determine which ports forward traffic and which block. Understanding root, designated, blocked, and alternate ports is essential to predicting network behavior and troubleshooting convergence issues.
Spanning Tree Protocol is the foundation of loop-free switched networks. Without it, redundant links create broadcast storms and MAC table corruption. This article explains the bridge loop problem and how STP solved it.
On multi-access OSPF networks, the DR and BDR centralize LSA exchange so routers do not flood 45 sessions across 10 neighbors. A practical guide to what the DR and BDR do and why OSPF design depends on them.
Put 200 routers in one OSPF area and SPF, LSDB size, and flooding all break down. Areas fix scalability by isolating LSAs, SPF runs, and flooding. A plain-English guide to OSPF area design and why Area 0 is special.
OSPF neighbors progress through 8 states from Down to Full, and understanding the packet exchange at each step is the key to troubleshooting adjacency problems. A guide to OSPF neighbor states with real packet captures.
Router IDs, ABRs, ASBRs, stub areas, LSAs, costs, and adjacencies: the OSPF vocabulary is large. A plain-English reference to the key terms and concepts every network engineer working with OSPF should know.
Interface-based OSPF configuration (ip ospf [process] area) skips wildcard masks and makes per-port membership obvious. Here is when to use it and how.
Passive interface stops OSPF Hellos on user VLANs while still advertising the subnet. Learn how it works, how to configure it, and how to verify without breaking adjacencies.
A full R1/R2/R3 single-area OSPF lab with IP plan, router ospf config, and the show commands that prove neighbors are Full and routes are installed.
