About GTIN(MPN/ UPC/ EAN/ ISBN)

About the requirements of MPN EAN UPC, you may visit the following website:
http://pages.ebay.com/sell/item_specifics/product_identifiers.html

EAN (European Article Number), UPC (Universal Product Code) ISBN (International Standard Book Number) are all GTIN (Global Trade Item Number).
MPN (Manufacturer part number) is a series of numbers and/or letters that has been given to a part by the manufacturer, identifies the part as belonging to and originating from that one manufacturer. EAN and UPC is a unique identifier for a product. It functions like an identity card for an individual. It is a one-to-one relationship. One-to-many relationship does not exist.

EAN is for selling to Europe, and UPC is for selling to North America.
 
last updated 20170705.
Ref: http://www.cifnews.com/article/27036