Open Shortest Path First (OSPF) is a routing protocol developed for Internet Protocol (IP)
networks by the Interior Gateway Protocol (IGP) working group of the Internet Engineering
Task Force (IETF). Which two statements best describe the OSPF link-state routing
protocol? (Choose two.)

A.
OSPF sends updates every 10 seconds.

B.
OSPF sends triggered updates when a network change occurs.

C.
When a link state is changed, the router that detected the change creates a link-state
advertisement (LSA) and propagates it to all OSPF devices using the 224.0.0.6 multicast
address.

D.
OSPF sends summaries of individual link-state entries every 30 minutes to ensure LSDB
synchronization.

Explanation:
The point of this question is the basis of OSPF.
Incorrect answer A. OSPF send hello packets every 10 seconds, not the updates, OSPF
sends triggered updates when a network change occurs. For OSPF, D Rother use the
multicast address 224.0.0.6 to send packets to DR and BDR, only DR and BDR can get the
information from this multicast address.