Explanation OSPF uses multicast to communicate routing updates among routers within the same area. OSPF routers send and receive link-state advertisements (LSAs) using IP multicast addresses 224.0.0.5 (all OSPF routers) and 224.0.0.6 (all OSPF designated routers) 1. Multicast allows OSPF to send routing updates efficiently and selectively, without flooding the entire network or requiring acknowledgments from every router