OSPF Open Shortest Path First

 This protocol is a link state that supports large networks.  

Order of OSPF Operations:
  1. Discover neighbors
  2. Form adjacencies
  3. Share Links by Flood Link State Database
  4. Compute shortest path
  5. install best routes
  6. Respond to network changes
Basic Configuration

Begin by creating a loopback interface on each router.  Then enable single area OSPF oon each router.  Uses wildcard mask (inverse) of the subnet.  The loopback interfaces have the last number of the octet changed, which logically makes sense, but I kept entering this wrong on the CLI. Lots of mistakes to get to his point. I was finally able to verify that the routers formed adjacencies. 


Relief when I finally got this:



Next I checked the cost to see that no traffic is being routed through R5 20.0.3.2:
After that, I sat the bandwidth to 100 GBPS to have a cost of 1






















































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