This is a numeric identifier for the remote FCIP entity this link connects to, distinct from its WWN or IP address. This identifier is what internally distinguishes multiple links or routes pointing at logically different remote entities even when other identifying details might otherwise overlap, particularly relevant in the dynamic routing table that references links by this kind of identity. In a topology with several remote FCIP entities behind different addresses, this identifier lets the local device's routing logic disambiguate which specific remote entity a given dynamically-discovered route actually leads to.