This read-only counter reports how many subnet-level FFT entries currently share the same ECMP next-hop set as a given entry. An administrator uses this to understand how heavily a particular load-balanced path is reused across the forwarding cache, which matters if that next-hop set needs to be changed or invalidated. For example, a high rlInetFftSubNextHopSetRefCount for a next-hop set means many destination subnets rely on that same group of ECMP paths, so a failure there would affect a broad swath of cached routes.