EIGRP - DUAL Algorithm and FD Set to Infinity

During the EIGRP DUAL (Diffusing Update Algorithm) process in networking, the Feasible Distance (FD) is set to infinity to indicate that the router is in a transitional state. This occurs when the router is actively seeking alternative paths. Setting the FD to infinity marks the route as temporarily invalid while the router queries its neighbors and waits for replies to determine a new viable path. This state is known as the active state.

https://networklessons.com/eigrp/eigrp-dual-fsm-finite-state-machine