Volume 1 - Chapter 22: Implementing Basic OSPF Features Flashcards
What is the command to enter OSPF configuration mode for a particular OSPF process?
router ospf processID
What is the command to set a router-ID for an OSPF process?
router-id routerID
Assuming a RID has not been manually set, what is the order that the router will use to choose its router-ID dynamically?
The router will choose the highest working loopback.
If no loopback is configure/working, then the highest IP address of any non-loopback interface.
What is the command to enable OSPF for a specific network, rather than on a per-interface basis?
network x.x.x.x wildcardmask area areaID
What are the range of values for the OSPF area ID?
The area can be configured as an integer or dotted decimal format in the range of 0 to 4,294,967,295.
A technician enters the following network into the OSPF configuration:
network 172.16.3.2 0.0.255.255 area 0
How with the router interpret this command?
The subnet has been configured incorrectly and does not match the wildcard mask. However, IOS will perform the math to calculate the subnet ID and enter that into the running configuration as:
network 172.16.0.0 0.0.0.255 area 0
What are the commands to show the configuration commands of OSPF?
show running-config
show ip protocols
What are the commands to show the status of OSPF-enabled interfaces?
show ip ospf interface
show ip ospf interface type number
show ip ospf interface brief
What are the commands to show the status of OSPF neighbors?
show ip ospf neighbor
show ip ospf neighbor type number
What is the command to display the current LSDB?
show ip ospf database
What is the command to display the current RIB?
show ip ospf rib
A technician runs the command show ip ospf neighbor and sees the following state for one of its neighbors:
FULL/DR
What does this tell us about the neighbor?
The router has reached a full state and exchanged the LSDB with its neighbor.
The neighboring router is a designated router.
A technician runs the command show ip ospf neighbor and sees the following state for one of its neighbors:
FULL/BDR
What does this tell us about the neighbor?
The router has reached a full state and exchanged the LSDB with its neighbor.
The neighboring router is a backup designated router.
A technician runs the command show ip ospf neighbor and sees the following state for one of its neighbors:
FULL/DROTHER
What does this tell us about the router the technician is currently connected to?
The technician is currently logged into either the DR, or BDR.
This router has reached a full state and exchanged the LSDB with its neighbor.
A technician runs the command show ip ospf neighbor and sees the following state for one of its neighbors:
2WAY/DROTHER
What does this tell us about the neighbor and the router the technician is logged into?
Neither router is a DR or BDR. As such, the routers cannot reach a full state and will not exchange their LSDBs with each other.
