The count to infinity problem occurs when routers keep incrementing metrics for a failed route until reaching infinity.
Example:
Router A loses its direct route to
Router B still has a route via A (metric )
Router A learns from B, adds , gets metric
They keep incrementing until reaching
With RIP's -second timer, this takes minutes. During this time, packets loop. Split horizon, route poisoning, and hold-down timers minimize this problem.