IBM Support

IT16726: PCOM: 3270 TLS 1.2 SESSION RUNS SLOW WITH SCREEN SIZE LARGER THAN 27X150

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APAR status

  • Closed as program error.

Error description

  • Replaced PCOMM v6.0.11 with v12 and any screen size larger than
    27X150 gets responses measured in minutes. Smaller screen sizes
    are fine. PCOM V6.0.12 had the same problem.
    

Local fix

  • Add keyword - ReceiveBufferSize=32768 to Telnet3270 section of
    WS profile
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * IBM Personal Communications secure sessions with screen      *
    * sizes 27x132 and larger.                                     *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * Slow secure emulator session response to host updates when   *
    * using screen size of 27x132 and larger.                      *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    IBM Personal Communications secure emulator sessions created
    with larger screen sizes (27x132 and beyond) may slow down when
    the emulator communicates with the host. For example, while
    using 62x160 screen size, page up and page down operations may
    show X-CLOCK for several minutes, and keyboard is inhibited
    during this period.
    

Problem conclusion

  • In a secure session, default buffer size of the receiving data
    buffer is set to 16K. This was found to cause issues when
    encrypted data was larger than the buffer size. PCSTLNET.DLL has
    been changed to set the default receive buffer size for a secure
    session to 32K. We recommend our users not to customize the
    receive buffer size while configuring the emulator sessions.
    Fix scheduled for IBM Personal Communications 6.0.18 Refresh
    Pack and 12.0.1.0 Refresh Pack
    

Temporary fix

Comments

APAR Information

  • APAR number

    IT16726

  • Reported component name

    PCOMM COMBO-ENC

  • Reported component ID

    5639I7000

  • Reported release

    C00

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2016-08-23

  • Closed date

    2016-09-16

  • Last modified date

    2016-09-28

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

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

Fix information

  • Fixed component name

    PCOMM COMBO-ENC

  • Fixed component ID

    5639I7000

Applicable component levels

  • R60G PSY

       UP

  • RC00 PSY

       UP

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Document Information

Modified date:
28 September 2016