This Integer32 gives the number of significant bits in the NetworkAddr field, defining how large a subnet this route covers. An admin uses it together with NetworkAddr to know the exact scope of the route, for example distinguishing a /24 branch subnet route from a /32 host-specific route. For example, a NetworkAddr of 10.20.30.0 with a prefix of 24 covers the entire 10.20.30.0/24 subnet, while a prefix of 32 would mean the route applies to a single host.