Under z/OS, IBM's eNetwork Communications Server is supported.
This document covers the following topics:
In z/OS environments, OpenEdition sockets (API=OES) or the high performance native sockets interface (API=HPS) are used to communicate with the IBM TCP/IP address space. A valid OpenEdition security context, referred to as an OMVS segment, must be defined for Entire Net-Work. For more information, see the IBM document z/OS OpenEdition Planning Guide.
If the OMVS segment is not properly defined, TCP/IP driver initialization will fail with error 156. The Entire Net-Work error message received is NETP600I if API=HPS or NETP700I if API=OES.