Hello Saravana,
1. For connections initiated by the SAP ERP system to SAP HCI, you need to add the root certificate from SAP HCI in the Trust Manager (STRUST) transaction in your ERP system.[ In this case SAP HCC is not required since the handshake happens with Certification Exchange ]
2. For connections initiated by SAP HCI to the SAP ERP system, the root certificate from your SAP ERP system needs to be added in the keystore in your SAP HCI tenant. This should have been taken care of during the initial setup phase by the Cloud Operations team.This requires SAP HCC if client don’t want to expose their IP address out of their Private Network.SAP HCC allocates Virtual Address which is internally mapped to SAP ERP.
As per my understanding SAP ERP -->SAP HCI- -> SF or any SAP Owned SaaS doesn’t require SAP HCC, but SF-->SAP HCI-->SAP ERP[ On Premise ] requires SAP HCC in between SAP HCI and SAP ERP.
Reqards,
Sriprasad Shivaram Bhat