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PK70363: LU6.2 CONNECTION BETWEEN 2 CICS REGIONS DO NOT RECONNECT AFTER NETWORK ERROR.REGION WENT MAXTASK MANY ALLOCATES DFHZC2411 0805

A fix is available

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APAR status

  • Closed as program error.

Error description

  • You are running CICS Transaction Server 2.3 and have 2 regions
    connected via LU6.2 (APPC).  The connection is acquired, when
    a network error occurred. Every session on both sides received
    the following message:
    DFHZC3471 Virtual route inoperative.
    The action taken on both sides for the SNASVCMG winner sessions
    included SIMLOGON.
    The timing of the sessions going away caused one side to think
    it needed CNOS - change number of sessions, to be redriven
    while the other side did not think CNOS was needed to be
    redriven- call this region A. The other region B. After this
    error we could see the following:
    Region A, went maxtask, due to many tasks being in ALLOCATE
    waits to region B.  The message log showed it established
    its SNASCVMG winner, but did not drive CNOS since it did not
    believe it was needed. Region B then bound its SNASVCMG winner,
    and is waiting for region A to drive CNOS, which it will never
    do.  Region A does attempt to bind its user session winners,
    but each is rejected by region b, since it is waiting for CNOS
    to be driven by region A. Here is the message issued on Region
    A for each user session it attempts to bind:
    DFHZC2403 E applid -AAO CSNE Bind failure. VTAM RETURN CODE 1001
              SENSE CODE 0805 0000 ((1) Module name: DFHZSYX)
    .
    Here is the corresponding message  issued on region B:
    DFHZC2411 E applid DUMY CSNE xxxxxxx attempted invalid logon.
               SENSE CODE 0805 0000 ((37 Module name: DFHZBLX)
    .
    Addional symptom(s) additional keyword(s):
    KIXREVBDB
    TCMEINT TCMECNO session limit exceeded
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED: All CICS users.                              *
    ****************************************************************
    * PROBLEM DESCRIPTION: Following a virtual route inoperative   *
    *                      network failure (DFHZC3471), the LU6.2  *
    *                      user sessions do not recover.           *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    A network failure occurs which results in a number of virtual
    route inoperative error messages DFHZC3471.
    
    In attempting to reestablish the APPC connection the OPNDST of
    the SNA Service Manager (SNASVCMG) Winner on one side fails with
    DFHZC2405 (Node not Active) which allows all the user sessions
    to be CLSDST. The TIDYUP routine in DFHZCLS then sets the
    maximum number of user sessions to zero.
    
    Meanwhile the partner, binds his SNASVCMG Winner but does not
    send CNOS because it is still in the process of CLSDST all the
    user sessions.
    
    The APPC connection appears to be ACQuired but because one side
    has run TIDYUP and set the maximum number of user sessions to
    zero it is impossible to bind any of the user sessions
    (DFHZC2411 instance 37). CNOS on the connection is not
    reinitiated by either CICS region and so it is not properly
    acquired.
    
    Additional Keywords
    ZC3471 ZC2411 ZC2405 DFHZC2403 ZC2403 DFHZC3470 ZC3470
    DFHZC3474 ZC3474
    

Problem conclusion

  • Error processing in DFHZNAC has been altered:
    (a) DFHZC3471 has been changed in the S12 exit so that a new
        flag (TCMENWF - network failure) is set when this error
        occurs.
    (b) DFHZC3461 has been changed in the S51 exit so that the check
        for whether CNOS has started (TCMECNO) is bypassed if a
        network failure (TCMENWF) has occurred. CNOS processing
        will then be reinitiated when the SNA Service Manager
        (SNASVCMG) Winner is rebound.
    
    DFHZCLS has been altered so that if neither of the SNASVCMG
    sessions are rebound before all the user sessions are CLSDST
    then CNOS will be reinitiated after DFHZCLS processes TIDYUP,
    only when this type of network failure has occurred.
    
    
    The following manuals have been changed :-
    (1) The CICS Transaction Server 3.1 Data Areas manual
    (GC34690200) will be updated as follows. The description
    of the TCME will be amended, and the reserved 1 byte slot
    at offset x'64' will be redefined to read:
       (64) BIT(8)        1   TCMECOM   Flags for comms failures
             1...  ....        TCMENWF  Network failure
    
    (2) The CICS Transaction Server 3.2 Data Areas manual
    (GC34686300) will be updated as follows. The description
    of the TCME will be amended, and the reserved 1 byte slot
    at offset x'64' will be redefined to read:
       (64) BIT(8)        1   TCMECOM   Flags for comms failures
             1...  ....        TCMENWF  Network failure
    

Temporary fix

  • FIX AVAILABLE BY PTF ONLY
    

Comments

APAR Information

  • APAR number

    PK70363

  • Reported component name

    CICSTS V3 Z/OS

  • Reported component ID

    5655M1500

  • Reported release

    400

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2008-08-12

  • Closed date

    2009-02-10

  • Last modified date

    2009-03-03

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

    PK66506

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

    UK43793 UK43795

Modules/Macros

  •    DFHBSM62 DFHTCPLR DFHTCTTE DFHTCTZE DFHZCLS
    DFHZGCN  DFHZNAC  DFHZNCA
    

Publications Referenced
GC34690200GC34686300   

Fix information

  • Fixed component name

    CICSTS V3 Z/OS

  • Fixed component ID

    5655M1500

Applicable component levels

  • R400 PSY UK43793

       UP09/02/13 P F902

  • R500 PSY UK43795

       UP09/02/17 P F902

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.

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Document Information

Modified date:
03 March 2009