The Designer creates a RANKINDEX port for each Rank transformation. The Integration Service uses the Rank Index port to store the ranking position for each row in a group.
For example, if you create a Rank transformation that ranks the top five salespersons for each quarter, the rank index numbers the salespeople from 1 to 5:
The RANKINDEX is an output port only. You can pass the rank index to another transformation in the mapping or directly to a target.