The real DESCRIPTION field here is just the auto-generated stub "Cisco UCS fabric:FcSanEp:aggrPortId managed object property", so it carries no real prose -- but the property name and its Gauge32 type tell you what it holds: It holds the breakout sub-port index of this FC SAN uplink port, used when the underlying physical port is a breakout cable split into several independent lower-speed lanes. If this FC SAN uplink port is not on a breakout port this simply reads 0; if it is lane 2 of a 4-way breakout cable, this field is what tells UCS Manager (and an admin reading the topology) which one of the four independent lanes this particular row describes. On a QSFP broken out into four lanes, this FC SAN uplink port might report aggrPortId 1 to mark it as the 1st of the four sub-ports.