NetView Program-to-Program Interface

The NetView® program-to-program interface enables application programs to send network management vector transport (NMVT) or control point management services unit (CP-MSU) requests to the NetView program and enables application programs to send data buffers to, or receive data buffers from, other application programs. An application program can be a sender program, a receiver program, or both. Application programs can send data buffers to, or receive data buffers from, other applications running in the same host as the NetView program, or in a different host.

Each receiver program has a buffer queue for temporary storage of incoming data buffers. These buffer queues reside in the program-to-program interface. A sender program sends a data buffer to a receiver buffer queue, and the receiver program retrieves the data buffer from the buffer queue.

When you define a program as a receiver, you also define the buffer queue limit, the maximum number of outstanding buffers that can be stored in the receiver buffer queue. When the receiver buffer queue is full, and other buffers are sent, the sender programs receive a return code of 35.

You can use the DISPPI command to display information about PPI buffer queues, including buffer limits, buffer queue lengths, total buffers sent, and buffer storage usage. This command displays information for the current receiver or receivers defined to the program-to-program interface. Figure 1 contains sample output from the DISPPI command.

DWO948I RECEIVER  RECEIVER  BUFFER      QUEUED      TOTAL       STORAGE
DWO949I IDENTITY  STATUS    LIMIT       BUFFERS     BUFFERS     ALLOCATED
DWO950I --------  --------  ----------  ----------  ----------  ----------
DWO951I NETVALRT  ACTIVE          1000           0          18           0
DWO951I DUIFSSCO  ACTIVE           100           0       10049           0
DWO951I PPICMDID  ACTIVE           100           0           0           0
DWO951I DUIATMGR  ACTIVE          1000           0        3287           0
DWO951I FNMRCVQ   ACTIVE            99           0       20111           0
DWO951I NPM60AP   ACTIVE            99           0       20111           0
DWO951I DUIFI000  ACTIVE          1000           0       15027           0
DWO968I END OF DISPLAY

Another command, DISBQL, displays buffer queue limits and the number of buffers currently available on the buffer queue. You can use the SETBQL command to reset the buffer queue limit of a receiver.

The program-to-program interface trace facility enables you to set up a trace in the program-to-program interface for either an individual receiver or all current and future receivers. The program-to-program interface trace facility writes a trace record each time a user defines, deactivates, or deletes a receiver to the program-to-program interface and each time a buffer is sent or received. You control the program-to-program interface trace facility with the TRACEPPI command. You can use the TRACEPPI command to start, stop, modify, or end the program-to-program interface trace facility. See the IBM® Tivoli® NetView for z/OS® Command Reference Volume 1 (A-N) or the NetView online help for more information about the TRACEPPI command.

See the IBM Tivoli NetView for z/OS Application Programmer's Guide for detailed information about the NetView program-to-program interface.