The XTI is a network-transparent protocol. In the z/OS® environment, XTI system support is a set of application calls to create the XTI protocol, as requested by your application. The services request is communicated to the XTI transport system using the RFC 1006 protocol mapper. RFC 1006 translates messages to transport class 0 service requests before passing them to the XTI.

Figure 1 is a high-level diagram to show how the XTI interface works in an z/OS environment.

Figure 1. Using XTI with TCP⁄IP

In the z/OS environment, external names must be eight characters or fewer. If the XTI application program interface names exceed this limit, those names longer than eight characters are remapped to new names using the C compiler preprocessor. This name remapping is found in a file called X11GLUE.H, which is automatically included in your program when you include the header file called XLIB.H. When debugging your application, you can refer to the X11GLUE.H file to find the remapped names of the XTI programs.