This INTEGER is the table index for a row describing a row of the blade/expansion-card WWN-GUID table, the number SNMP uses to line up every other VPD column (serial number, part number, manufacturer ID, and so on) that belongs to this same physical unit. The MIB itself cautions that this data should be walked as a full table rather than fetched one object at a time, since a stale poll of an individual column can be inconsistent with the rest of the row. For example, an admin walks bladeAndExpCardWwnGuidVpdIndex together with the eight bladeAndExpCardWwnGuidVpdN values sharing that same index to read a consistent set of storage identifiers for one card rather than a mix from two different cards.