This holds the Rn (Relative Name) — just the last path segment of the Dn — that identifies the parent container that groups every IP address pool defined in this UCS domain uniquely among its siblings under the same parent. UCS Manager builds the full Dn by concatenating parent Rns down the tree, so this field is the one segment specific to this instance rather than to the whole path. For this kind of object the Rn typically looks like 'ip-pool-ext-mgmt'.