How are EIGRP and OSPF similar?

Both EIGRP and OSPF are dynamic routing protocols that use hello packets to discover and maintain adjacencies with neighboring routers. This mechanism ensures that routers are aware of active neighbors and can exchange routing information. Autosummarization is a feature primarily of EIGRP (though often disabled in modern networks) and RIP, not OSPF. OSPF performs summarization manually at ABRs and ASBRs. Unequal-cost load balancing is a unique feature of EIGRP; OSPF only performs equal-cost load balancing. While both protocols can send some updates using unicast (e.g., specific queries or acknowledgments), their primary method for sending routing updates to multiple neighbors is multicast (EIGRP uses 224.0.0.10, OSPF uses 224.0.0.5 and 224.0.0.6).