This DateAndTime value is the timestamp of the last update to this internal link record 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 it tells an admin how current the switch-side view of this link actually is, which matters when correlating a fabric-interconnect-reported event against other logs. A ts value from before a reported chassis reseating on this link's fabric-interconnect side would tell an admin this switch-side record hasn't yet reflected the change.