What is the difference between OSPF and EIGRP, and when would you choose each in 2026?

OSPF is an open-standard link-state protocol using Dijkstra's algorithm, while EIGRP is Cisco's advanced distance-vector protocol using DUAL. OSPF floods LSAs across all routers in an area; EIGRP sends bounded updates only to affected neighbors. In 2026, choose OSPF for multi-vendor environments—Bangalore enterprises like Flipkart and Razorpay prefer it for vendor neutrality. Use EIGRP in pure Cisco shops (Cisco India, HCL) where sub-second convergence and simpler configuration matter. Interview tip: Mention OSPF area design and EIGRP's feasible successor concept—both are tested in Cisco interviews at Movate and Aryaka.