Ariba provides 3 options to connect SAP system to the Ariba Network on the cloud.
Option 1. Web Services interfaces can directly consume and sendcXML messages using Ariba Add-on. By removing the need for middleware the landscape is simplified.
Option 2. Web Services, mediated via SAP HANA Cloud Integration (HCI), for enhanced data protection and security. (New option)
Option 3. Web Services, mediated via SAP Process Orchestration (PI) or similar middleware, with the same use cases as HCI, but you can take advantage of your prior investments into PI.
The HCI connector has been recently added as an option to connect the two systems.
Simplified cloud integration for trading partners
Ariba Integration Gateway powered by SAP HCI
Next generation cXML& standards based support
Strong cXML governance for enhancements