IV31960: TCP CONNECTION MAY HANG - LAST FEW BYTES MAY NOT EVER BE SENT APPLIES TO AIX 7100-02

Obtain the fix for this APAR.

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 7100-02 Technology Level with
  * bos.net.tcp.client below the 7.1.2.15 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 IV31960.
  ****************************************************************
  

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 is sysrouted FROM one or more of the following:

  IV31959

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

  U856845

Fix information

• Fixed component name

  AIX V7.1

• Fixed component ID

  5765H4000

Applicable component levels

• R710 PSY U856845

     UP12/11/26 I 1000