Multicast Open Shortest Path First (MOSPF) is a routing protocol designed to efficiently manage multicast traffic within an Internet Protocol (IP) network. It extends the capabilities of the standard Open Shortest Path First (OSPF) protocol by enabling routers to share information about multicast group memberships and the best paths to reach those groups. MOSPF operates by using link-state routing principles, allowing routers to maintain a complete view of the network topology. This helps in determining the optimal routes for multicast data packets, ensuring that they reach all intended recipients without unnecessary duplication or congestion.