The SAP Remote Function Call (RFC) is a proprietary protocol for communication between SAP systems or between an SAP system and an external application. Its implementation is fundamentally based on two key technologies:

1. TCP/IP: This is the foundational network protocol suite used for data transmission. RFC relies on TCP/IP for reliable, connection-oriented communication across the network, ensuring that data packets are delivered in order and without errors.

2. CPI-C (Common Programming Interface for Communications): This is an API standard, originally from IBM's Systems Application Architecture (SAA), which defines a platform-independent interface for program-to-program communication. SAP adopted this model for its RFC interface to establish and manage logical conversations between communicating programs.

A. EDI: Electronic Data Interchange (EDI) is a standard for structuring and exchanging business documents (like purchase orders), not a low-level communication protocol that RFC is built on.

D. OData: The Open Data Protocol (OData) is a modern, web-based protocol built on HTTP and REST principles. It is used for SAP Fiori and other UI5 applications, but it is a separate technology from the classic, binary RFC protocol.

1. SAP Help Portal

SAP NetWeaver Application Server for ABAP 7.52: In the section on "Classic RFC

" the documentation states

"The RFC interface is a protocol based on CPI-C and TCP/IP. It is used for communication between SAP systems

or between an SAP system and an external system."

Source: SAP Help Portal

Classic RFC

Document Version: 7.52.

2. SAP Help Portal

SAP NetWeaver Application Server for ABAP 7.52: The documentation on CPI-C explicitly links it to RFC: "The RFC and CPI-C services are part of the SAP Communication Services of the presentation interface." It further clarifies that CPI-C provides the underlying communication model.

Source: SAP Help Portal

Common Programming Interface for Communications (CPI-C)

Document Version: 7.52.

3. Official SAP Training Material (e.g.

TADM10/TADM12): Courseware for SAP System Administration consistently describes the SAP NetWeaver AS ABAP architecture

identifying the RFC interface as a key communication mechanism that operates over the TCP/IP network layer and is conceptually derived from the CPI-C standard.

Source: SAP Education Course TADM10 - SAP S/4HANA Implementation Tools & ASAP

Unit on Technology Fundamentals.