gtps2m2rACF/SNA Data Communications Reference

Session Management Request Services

The following services may be requested:

The TPF SNA system segment (CSU0) is provided for applications to request the session services.

Starting Session Management Request Services

To start a particular session service, a TPF application:

CSU0 resides in all subsystems.

The ISHLL macro defines the parameter area that should reside in working storage. The parameter area settings for each service call are described in detail in Table 7, Table 8, and Table 9.

The service program (CSU0) sets the return code field (ISHLRC) in the parameter area and returns control to the calling program.

Table 7. CSU0 Interface

Interface Input to CSU0 Returned from CSU0
Registers R1: ISHLL Parameter List Address R0-R7: Not changed
ECB Workarea
  • EBX012-EBX041 reserved for system use
  • Remaining ECB fields irrelevant

  • EBX012-EBX041 unpredictable
  • Remaining ECB fields not changed

Data Levels Irrelevant Not Changed
Protect Key Working Storage Working Storage

Requesting Session Resynchronization


Table 8. Request Session Resynchronization Interface

Label Length (In Bytes) Description
ISHLREQ 1 X'01' RESYNCH SESSION REQUEST
ISHLTYP 1 Reserved
ISHLRC 1 Return Code (output only)
  1. X'00' Request scheduled
  2. X'11' PLU name conversion error.
  3. X'12' ISHLPNAM is not defined as a primary LU.
  4. X'13' PLU not available.
  5. X'21' SLU name conversion error.
  6. X'22' SLU already in session.
  7. X'23' SLU is pending activation.
  8. X'24' ISHLSNAM is defined as a primary LU.
  9. X'26' SLU not available.
  10. X'27' PLU/SLU domain error.
  11. X'41' Invalid request code.
  12. X'42' System is not in NORM state.
  13. X'43' CSCD can not schedule the request.
  14. X'44' Invalid request type.
  15. X'45' Resynch valid only for LU using PSV with DFC ownership.
ISHLSW 1 Indicator, reserved for TPF internal usage.
ISHLSNAM 4 Secondary LU Name Address

The address of a 16-byte field that contains the NETID and the Network Qualified LU name of the resource functioning as secondary LU (SLU) for the requested session. The NETID is an 8-character string left-justified and padded with blanks. The name, which immediately follows the NETID, is also an 8-character string left-justified and padded with blanks.

ISHLPNAM 4 Primary LU Name Address

The address of a 16-byte field that includes the NETID and the Network Qualified LU name of the resource functioning as primary LU (PLU) for the requested session. The NETID is an 8-character string left-justified and padded with blanks. The name, which immediately follows the NETID, is also an 8-character string left-justified and padded with blanks.

Requesting Session Termination Interface


Table 9. Request Session Termination Interface

Label Length (In Bytes) Description
ISHLREQ 1 Deactivate Session Request (X'02')
ISHLTYP 1 Type of Deactivation
  1. Normal (X'01')
  2. Forced (X'02')
ISHLRC 1 Return Code (output only)
  1. X'00' Request scheduled
  2. X'11' PLU name conversion error.
  3. X'12' ISHLPNAM is not defined as a primary LU.
  4. X'21' SLU name conversion error.
  5. X'24' ISHLSNAM is defined as a primary LU.
  6. X'28' SLU is not in session.
  7. X'29' SLU is not in session with ISHLPNAM.
  8. X'2A' A zero PSV index is found in PSV name table.
  9. X'41' Invalid request code.
  10. X'42' System is not in NORM state.
  11. X'43' CSCD can not schedule the request.
  12. X'44' Invalid deactivation type requested.
ISHLSW 1 Indicator, reserved for TPF internal usage.
ISHLSNAM 4 Secondary LU Name Address

The address of a 16-byte field that contains the NETID and the Network Qualified LU name of the resource functioning as secondary LU (SLU) for the requested session. The NETID is an 8-character string left-justified and padded with blanks. The name, which immediately follows the NETID, is also an 8-character string left-justified and padded with blanks.

ISHLPNAM 4 Primary LU Name Address

The address of a 16-byte field that contains the NETID and the Network Qualified LU name of the resource functioning as primary LU (PLU) for the requested session. The NETID is an 8-character string left-justified and padded with blanks. The name, which immediately follows the NETID, is also an 8-character string left-justified and padded with blanks.