The scenario
Workstation (10.0.10.10/24) is cabled to Access Switch, and so is Edge Router's ge0 (10.0.10.1). Edge Router's ge1 (172.16.20.1) connects straight to Server (172.16.20.20/24) on a second subnet. Workstation's default gateway is 10.0.10.1 and Server's is 172.16.20.1. This is a small version of a real campus: PCs plug into access switches, and everything bound for another network goes through a router. The switch is invisible to IP; it simply puts Workstation and the router's ge0 on the same LAN.
What you will work out
Trace traffic across a switch and a router, and see that the switch is the workstation's only path to its gateway.
Why this matters
Most office and campus networks follow this pattern: wall port, access switch, uplink to a router, other networks beyond. It explains a common complaint, 'I can reach the PC next to me but not the file server on another floor': the neighbour is on the same switch and subnet, while the server depends on the gateway, the uplink, and a route back.
Running it
Campus Routing Demo opens on a canvas, already wired and addressed. Trace a packet through it hop by hop, or run the same topology live on real Linux network namespaces. How the two modes differ.
Open Campus Routing Demo
Runs in your browser. No install, no signup, and the simulation starts instantly.
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