OA25586: ABEND0A9 WITH REASON CODE FF27 AT OFFSET X'C9A' IN ISTTRQNW.

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• The problem is that the TGREC was freed, but the trees were
  not marked so that they could be rebuilt.  The Abend0a9 occurred
  when finding a free record in the tree.
  Abend savearea chain:
   TRCRT -> TRRRR -> TRROB -> TRRCT -> TRRGT -> TRQNW -> TRCLT
   CURRENT SAVE AREA = TRQNW
  

Local fix

• Contact Level/2 support.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: All APPN users who change an APPN node from  *
  *                 a network node to an end node.               *
  ****************************************************************
  * PROBLEM DESCRIPTION: ABEND0A9 FF27 in ISTTRQNW attempting    *
  *                      to set up a session.                    *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  In the following configuration, XN2 is an NN and a session is
  set up between the PLU on NN1 and the SLU on NN3:
  
  NN1 ------ XN2 ------ NN3
  
  This creates a routing tree in NN1: NN1->XN2->NN3. The XN2->NN3
  TGs are queued on the NN3 tree record.
  
  All connections are inactivated and XN2 is restarted as an EN.
  When the TG between NN1 and NN2 is activated, NN1 detects the
  node role change from NN to EN. Since the existing TGs that
  originated in XN2 are known throughout the network, NN1 must
  make sure that they are no longer used by other NNs for route
  calculation. To do this, NN1 marks them INOP and sends out TDUs
  to inform all other NNs, then frees the TG records in its own
  database.
  
  To make sure all of the existing routing trees that contain
  XN2 are rebuilt, a call is made to the modules that mark trees,
  passing indicators that a node (XN2) has changed. However, a
  type of "change" means that a node's weight might change, not
  that the node should be removed from the tree. So when the
  tree is used for an new session request later, the existing tree
  records for XN2 and NN3 are reused. Since the freed TG records
  are still queued on NN3's tree record, ISTTRQNW issues an
  ABEND0A9 when it finds that these TG records no longer exist.
  
  In this case, since ENs should never be part of a routing tree,
  the indicator should have been "delete" instead of "change". A
  "delete" will cause the tree record for XN2, and every tree
  record in the tree below XN2, to be deleted and the tree is
  rebuilt without XN2.
  

Problem conclusion

• Modules ISTTRTTG and ISTTRINP have been changed to indicate
  a node is deleted, not changed, when a node role change from
  NN to EN is detected. ISTTRTTG detects a node role change
  for an adjacent node when the first TG to that node is
  activated. ISTTRINP detects a node role change for a
  non-adjacent node when a TDU is received for the node.
  
  Module ISTTRCRT has been included for maintenance purposes.
  

Temporary fix

Comments

APAR Information

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

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

  UA41975 UA41976 UA41977 UA41978 VM64609 DY47019

Modules/Macros

• ISTTRCRT ISTTRINP ISTTRTTG
  

Fix information

• Fixed component name

  VTAM V4 MVS/ESA

• Fixed component ID

  569511701

Applicable component levels

• R1A0 PSY UA41975

     UP08/08/12 P F808

• R170 PSY UA41976

     UP08/08/12 P F808

• R180 PSY UA41977

     UP08/08/12 P F808

• R190 PSY UA41978

     UP08/08/12 P F808

Fix is available

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