The Control Plane: Link State Routing
In this lesson, we'll study link state routing.
-Another way to create a routing table with the most efficient path between two routers or ‘nodes’ is by using link-state routing.
Link state routing works in two phases: reliable flooding and route calculation. Let’s look at phase I now.
Phase I: Reliable Flooding
Neighbor Discovery
When a link-state router boots, it first needs to discover its neighbors. To do this:
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Each router sends a HELLO message every seconds on all of its interfaces. This message contains the router’s unique address.
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As its neighboring routers also send HELLO messages, the router discovers its neighbors.
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These HELLO messages are only sent to neighbors that are directly connected to a router, and a router never forwards the HELLO messages that they receive. ...