Interactive OSPF Playground
Explore shortest-path selection in a three-router area.
Pink links mark the selected route from A to C. Move the sliders or take the direct link down. Try making both routes cost the same.
A → B → C · Cost 20
From A to C, compare the direct link with A → B + B → C. This small, single-area model shows cost selection after convergence. It does not simulate packet exchange, timers or the full OSPF state machine.