OA26082: CROSS DOMAIN LU TO LU SESSION FAILS WITH SENSE 08120000.

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• Cross domain session failure to TSO with sense 0812.  Module
  ISTTSCTK set sense 0812 while processing outbound BIND request.
  The BSBADD failed with Rtnd code '08', indicating LFSID address
  limit reached.
  

Local fix

• A temporary solution is to V NET,INACT and V NET,ACT
  the AHHC connection from the VTAM which is setting
  the UNBIND 08120000.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: All using VTAM boundary function.            *
  *                 (i.e. AHHC, switched XCA LAN)                *
  ****************************************************************
  * PROBLEM DESCRIPTION: BIND request fails with SENSE           *
  *                      08120000 across FID2 connection.        *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  Sample Configuration:
  
     VTAMA===AHHC===VTAMB
     APPLA          APPLB
  
  1) APPLA sends a BIND to APPLB across an AHHC connection.
  2) VTAM boundary function on VTAMA generates an LFSID to
     be used for this session.
  3) When the session is terminated on APPLA, module ISTTSCPS
     will set TSCHSIMD bit to indicate an internal UNBIND
     response is required even though the UNBIND type is not
     an immediate flavor.
  4) When this occurs, VTAM boundary function must not reuse
     the LFSID for this connection until VTAMB responds to
     the UNBIND request.  At that time, VTAMA must revalidate
     the LFSID for this connection.
  5) On VTAMA, the TSCHSIMD bit will be propagated to the
     BSB_HSIMD bit within the BSB.
  6) When the UNBIND request is written out, module
     ISTTSCIB issues a BSBREX DELETE to free the
     BSB from the REX hash table.  Module ISTTSCB1 will
     remove the BSB from the REX hash table but will not
     free the LFSID as the BSB_HSIMD bit is on.
     A specific BSBREX DELETE FREEADDR macro must be issued
     later when the real UNBIND rsp is received from VTAMB.
  7) In our case the SIO which writes out the UNBIND request
     is hung in the channel end appendage long enough for
     VTAMB to send an UNBIND cleanup (x'0F') request to end
     the session.
  8) When VTAMB sent the UNBIND cleanup, it deleted its BSB
     representing the session from the Rex hash table.  This
     means no more data will flow out from  VTAMB for this
     session.
  9) When VTAMA processes the UNBIND request, module ISTTSCNT
     discards it with reason code 9, indicating the BSB
     LU session state is reset.
  9) Now when the write channel program completes the
     BSB is REX deleted and the LFSID is not freed.
     An UNBIND response is never going to be received from
     VTAMB to cleanup the LFSID.
  
     Over time this timing problem can lead to many LFSIDs
     being lost by the AHHC connection.  Eventually BIND
     failures will occur with SENSE 08120000.
  
     A temporary solution is to V NET,INACT and V NET,ACT
     the AHHC connection from the VTAM which is setting
     the UNBIND 08120000.
  

Problem conclusion

• ISTTSCB1 - Added a TSNS VIT entry to trace when a FREEADDR
             (LFSID free) is not performed during a BSBREX
             DELETE call.
  ISTTSCBD - After the BSB for the session is located, code
             has been changed to set the BSB_FREE_LFSID bit
             on when processing an UNBIND request or response
             from the partner (TSCIMMED not on) and the NCB
             which this process is running under is not an
             RPNCB.  This allows the BSBREX DELETE call for
             the internal UNBIND rsp to free the LFSID
             immediately.
  ISTBSCRT - Included for maintenance purposes.
  

Temporary fix

• *********
  * HIPER *
  *********
  

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

  UA43104 UA43105 UA43106 UA43107

Modules/Macros

• ISTBSCRT ISTTSCBD ISTTSCB1
  

Fix information

• Fixed component name

  VTAM V4 MVS/ESA

• Fixed component ID

  569511701

Applicable component levels

• R1A0 PSY UA43104

     UP08/09/19 P F809

• R170 PSY UA43105

     UP08/09/19 P F809

• R180 PSY UA43106

     UP08/09/19 P F809

• R190 PSY UA43107

     UP08/09/19 P F809

Fix is available

• Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.