This part of ISO/IEC 19500 specifies a comprehensive, flexible approach to supporting networks of objects that are distributed across and managed by multiple, heterogeneous CORBA-compliant Object Request Brokers (ORBs). The approach to inter-ORB operation is universal, because elements can be combined in many ways to satisfy a very broad range of needs. This part of ISO/IEC 19500 covers the specification of: • ORB interoperability architecture • Inter-ORB bridge support • The General Inter-ORB Protocol (GIOP) for object request broker (ORB) interoperability. GIOP can be mapped onto any connection-oriented transport protocol that meets a minimal set of assumptions defined by this standard. • The Internet Inter-ORB Protocol (HOP), a specific mapping of the GIOP which runs directly over connections that use the Internet Protocol and the Transmission Control Protocol (TCP/IP connections). • The CORBA Security Attribute Service (SAS) protocol and its use within the CSIv2 architecture to address the requirements of CORBA security for interoperable authentication, delegation, and privileges. This part of ISO/IEC 19500 provides a widely implemented and used particularization of ITU-T Rec. X.931 | ISO/IEC 14752. Open Distributed Processing — Protocol Support for Computational Interactions. It supports interoperability and location transparency in ODP systems.