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IV20656: TCP CONNECTION MAY HANG - LAST FEW BYTES MAY NOT EVER BE SENT APPLIES TO AIX 7100-01

A fix is available

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APAR status

  • Closed as program error.

Error description

  • A tcp connection can hang and never send the last bytes
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED:
    * Systems running the 7100-01 Technology Level with
    * bos.net.tcp.client below the 7.1.1.18 level.
    ****************************************************************
    * PROBLEM DESCRIPTION:
    * An established tcp connection can hang and never send the last
    * bytes.  This has been seen primarily on VIO Clients, when
    * transferring large amounts of data.
    *
    * It happens when the send for the previous packet is
    * ACKed all at once before the call to ip_output returns back to
    * tcp_output.
    *
    * To determine if you're experiencing this problem, run
    * 'netstat -an' in a 5 sec loop.
    * If you notice the Send-Q value has the same non-zero value for
    * the same established connection after a couple of iterations,
    * you may be experiencing this problem.
    ****************************************************************
    * RECOMMENDATION:
    * Install APAR IV20656.
    * Prior to fix availability, an interim fix is available from
    * ftp://public.dhe.ibm.com/aix/ifixes/iv20656/
    ****************************************************************
    

Problem conclusion

  • TCP code is modified to record all acknowledgement recepits
    and make sure those last bytes were also sent. This change
    solves tcp hang issue
    

Temporary fix

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

Comments

APAR Information

  • APAR number

    IV20656

  • Reported component name

    AIX V7.1

  • Reported component ID

    5765H4000

  • Reported release

    710

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    YesHIPER

  • Submitted date

    2012-05-04

  • Closed date

    2012-10-02

  • Last modified date

    2013-11-23

Fix information

  • Fixed component name

    AIX V7.1

  • Fixed component ID

    5765H4000

Applicable component levels

  • R710 PSY U859421

       UP13/04/30 I 1000

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Document Information

Modified date:
23 November 2013