When a customer clicks on an affiliate link/banner and lands on your site integrated with the click tracking code (or lands on a replicated site), the click tracking code sends a request to the server which replies a PAPVisitorId (a unique 32-character-long alpha-numeric string).
This PAPVisitorId is saved in cookies and it gets saved in the database of PAP/PAN if the click was associated with an affiliate.
The PAPVisitorId inside the database of PAP/PAN stores the following data:
merchant account id (in PAP it is always 'default1')
IP address of the customer
details of the affiliate whose link/banner was clicked
banner id, campaign id
date of visit
time validity of the particular PAPVisitorId (cookie limit that can be set inside the campaigns of PAP/PAN)