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Concept Explainer · Enterprise IT & Networks

Static vs. Dynamic Routing — Why One Route Never Notices a Failure and the Other Reroutes Around It

A static route keeps doing exactly what it was told, forever — even after the path it points to is dead. A dynamic routing protocol is built to notice that and do something about it. That difference is the entire tradeoff.

A static route is a routing table entry an engineer typed in by hand: "to reach network X, send traffic out this interface, to this next hop." It never changes on its own. It doesn't matter whether the link it depends on is up, down, congested, or has been unplugged and hauled off to another building — the router keeps forwarding traffic to that next hop because that's literally the only instruction it has. A dynamic routing protocol— OSPF, BGP, EIGRP, and others — is the opposite kind of thing entirely: routers running it continuously discover their neighbors, exchange reachability information about the networks they can see, and recalculate the best path whenever that information changes. When a link fails, routers running a dynamic protocol notice within seconds (or less) and recompute a path around the failure automatically, with no human involved. Neither approach is a lesser version of the other — they solve the "how does a router decide where to send this packet" problem in two genuinely different ways, and the right one to use depends entirely on what the network actually looks like.