Dynamic routing is a concept opposite to static routing, which means that routers can automatically build their own routing tables based on specific routing information exchanged between routers, and can automatically adjust in time according to changes in links and nodes. When a node or a link between nodes in the network fails, or there are other available routes, dynamic routing can select the best available route by itself and continue to forward packets.
principle
The operation of the dynamic routing mechanism depends on two basic functions of the router: timely exchange of routing information between the routers and maintenance of the routing table:
Routers exchange routing information in a timely manner.
The reason why dynamic routing can automatically calculate the route and select the forwarding path according to the network situation is because when the network changes, the routing information exchanged between the routers will inform the other party of this change in the network. Through the information diffusion, all routers can Learn about network changes.
The router processes the collected routing information into a routing table according to a certain routing algorithm (different algorithms of different dynamic routing protocols) for the router to consult when forwarding IP packets.
When the network changes, after collecting the latest routing information, the routing algorithm recalculates to obtain the latest routing table.