Changing the way you learn

IPv4 Routing Protocols

Goals
1. To dynamically learn and fill the routing table with a route to each subnet in the internetwork.
2. If more than one route to a subnet is available, to place the best route in the routing table.
3. To notice when routes in the table are no longer valid, and to remove them from the routing table.
4. If a route is removed from the routing table and another route through another neighboring router is available, to add the route to the routing table.
5. To work quickly when adding new routes or replacing lost routes. (The time between losing the route and finding a working replacement route is called convergence time.)
6. To prevent routing loops.
General steps for learning routes
1. Step 1. Each router, independent of the routing protocol, adds a route to its routing table for each subnet directly connected to the router.
  1. Step 2. Each router’s routing protocol tells its neighbors about the routes in its routing table, including the directly connected routes, and routes learned from other routers.
    1. Step 3. After learning a new route from a neighbor, the router’s routing protocol adds a route to its IP routing table, with the next-hop router of that route typically being the neighbor from which the route was learned.

IPv4 Routing Protocols

	Created by jce299792458 about 11 years ago