OA41151: DURING PSRETRY PROCESSING THE OPTIMAL PATH IS NOT CHOSEN

A fix is available

Subscribe

You can track all active APARs for this component.

APAR status

  • Closed as program error.

Error description

  • During a network outage an RTP PU is path switched to a back up
    route that has a higher weight then the original path. When the
    original path becomes available PSRETRY should switch the route
    back to the lower weight path. However the route remains on the
    higher weight path.
    

Local fix

  • Issue a Modify RTP ID=CNRxxxxx to force the path switch.
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED: All users of VTAM/RTP connections.           *
    ****************************************************************
    * PROBLEM DESCRIPTION: PSRETRY does not pick the best path.    *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    The problem may be summarized as follows:
    1. There is an RTP connection between zOS CS and a non-z/OS
       CS HPR node. PSRETRY is coded for VTAM.
    2. The non-VTAM HPR node sends in a Route Information segment
       as part of a path switch process, but THD_RIN_WEIGHT
       had a value of 0 set, indicating a path weight of 0.
    3. At the next PSRETRY interval, VTAM's RTP code sees the
       path weight of 0 and assumes that this is a special case
       where it needs to learn the weight of the route without
       path switching.  This leads to VTAM associating an
       incorrect weight with the HPR pipe.
    4. Later, when a better path is available, VTAM does not
       path switch to use that route because the weight that it
       mistakenly associated with the route selected by the
       non-VTAM HPR node makes that path appear to be just as good
       or better.
    

Problem conclusion

  • ISTRPCRI has been updated to set RPN_PATH_WEIGHT to x'FFFF'
    if the Route Information Segment arrives with a weight of
    0 and RPN_PATH_WEIGHT is non-zero. After this occurs, at
    the next PSRETRY interval, VTAM should force a path switch
    to the optimal weight and set the correct weight.
    
    ISTRPNCB defined a new constant for x'FFFF'.
    
    ISTRPCRT is included for maintenance purposes only.
    

Temporary fix

Comments

APAR Information

  • APAR number

    OA41151

  • Reported component name

    VTAM V4 MVS/ESA

  • Reported component ID

    569511701

  • Reported release

    1C0

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2013-01-09

  • Closed date

    2013-01-11

  • Last modified date

    2013-07-02

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

    OA41007

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

    UA67688 UA67689

Modules/Macros

  • ISTRPCRI ISTRPCRT ISTRPNCB
    

Fix information

  • Fixed component name

    VTAM V4 MVS/ESA

  • Fixed component ID

    569511701

Applicable component levels

  • R1C0 PSY UA67688

       UP13/06/10 P F306

  • R1D0 PSY UA67689

       UP13/06/10 P F306

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.



Rate this page:

(0 users)Average rating

Document information


More support for:

z/OS family

Software version:

1C0

Operating system(s):

z/OS

Reference #:

OA41151

Modified date:

2013-07-02

Translate my page

Machine Translation

Content navigation