Open Catalog Interface (OCI) is one of the standard formats used by SAP Supplier Relationship Management, ORDIGES Purchase-to-Pay, Microsoft Dynamics AX and other ERP/Purchasing Systems when connecting to external punch-out catalogs.
The OCI format is used to define the field mapping between the supplier's catalog and the SAP SRM shopping cart, to ensure that the data is transferred accurately and completely between source and receiver. This standard is used instead of XML or cXML.
References
Open Catalog Interface Wikipedia(Text) CC BY-SA