Cisco CCNA Exam Tutorial: Five OSPF Hub-And-Spoke Details You Must Know!
CCNA exam success depends greatly on knowing the details, and if there’s one protocol that has a lot of details, it’s OSPF! This is true particularly of hub-and-spoke networks, so in this CCNA OSPF tutorial we’ll take a look at some of the more important hub-and-spoke OSPF details. This will help you in working with real-world networks as well, since this OSPF network type is one of the more typical network topologies.
In OSPF, the hub must become the designated router (DR). The DR election’s deciding value is the OSPF interface priority, and the default value is 1. It’s not enough to set the hub’s OSPF interface to 2, however, since the spoke routers must not become the DR or BDR. You must set the spoke interfaces to an OSPF priority of zero.
R2(config)#int s0
R2(config-if)#ip ospf priority 0
This ensures that the spokes will not become the DR or BDR if the hub goes down.
The hub does require a bit more configuration, though. The neighbor command must be used on the hub to indicate the IP address of the potential...