This is the relative name — the short leaf identifier — that distinguishes this internal link object from its siblings under the same parent chassis/IOM object. It matters on the internal Ethernet link that carries a blade's traffic from the chassis I/O Module up to a Fabric Interconnect over the backplane because UCS Manager and its CLI/GUI construct the object's full path by appending this relative name to a fixed parent, so it is the piece that actually varies per link. An rn of fabric/port-27 on this backplane link identifies internal backplane port 27 specifically, as opposed to any of the chassis's other backplane ports.