This string is the hardware model identifier reported for this internal link's underlying component, as tracked on the Fabric Interconnect side. It matters on the same internal chassis backplane link, but the record kept on the Fabric Interconnect (switch) side rather than the IOM/server side because the fabric interconnect's own hardware model constrains the link's real capabilities, distinct from whatever model is reported for the IOM on the other end. A model value identifying the fabric interconnect hardware on this link's fabric-interconnect side tells an admin which switch platform's specifications (port count, speed) actually bound this link.