I131 is the form for travel document application, including re-entry permit, refugee travel document and advance parole. Re-entry permit and Advance parole use the same application form but have different requirement and may be processed in different service center. All re-entry permit applications are processed in NSC.
If interested, see the following website for the difference.
http://www.hooyou.com/advanceparole/ap_rp.html
If interested, see the following website for the difference.
http://www.hooyou.com/advanceparole/ap_rp.html