IT27403: AMQ9213: A communications error for Unexpected flow

APAR status

• Closed as program error.

Error description

• When using SHARECNV(0) on MQ server connection channels whilst
  transferring messages that are greater than 32304 bytes in size,
  client connections may experience MQRC_CONNECTION_BROKEN or
  MQRC_UNEXPECTED_ERROR channel disconnects and the following
  errors may be logged:
  
  AMQ9213: A communications error for Unexpected flow received
  during MQDISC call occurred.
  AMQ9208: Error on receive from host <host name>
  AMQ9504: A protocol error was detected for channel '<channel
  name>.
  AMQ6183: An internal IBM MQ error has occurred.
  AMQ9999: Channel '<channel name>' to host '<host name>' ended
  abnormally.
  
  An First Data Capture (FDC) report with the following
  characteristics may also be logged:
  
   Probe Id          :- DN138001
   Major Errorcode   :- rrcE_COMMUNICATIONS_ERROR
   Probe Type        :- MSGAMQ9213
   Probe Description :- AMQ9213: A communications error for
  Unexpected flow
    received during MQDISC call occurred.
  

Local fix

• Alter the value of SHARECNV for the server-connection channel
  from 0 to 1 or higher (the default is 10).
  

Problem summary

• ****************************************************************
  USERS AFFECTED:
  Multi-threaded Windows .NET MQ client applications using the MQ
  .NET client library and a server connection channel with
  SHARECNV(0) configured. Problems are observed when such channels
   receive messages greater than 32304 bytes in size.
  
  
  Platforms affected:
  Windows
  
  ****************************************************************
  PROBLEM DESCRIPTION:
  A small timing window in the MQ .net client code can cause
  messages greater than 32304 bytes in size to be handled
  incorrectly in multi-threaded applications. This may cause MQ
  TSH packets to be corrupted resulting in channel disconnects and
  communication flow errors.
  

Problem conclusion

• The MQ .NET client code has been corrected to resolve this
  problem.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
  Version    Maintenance Level
  v8.0       8.0.0.12
  v9.0 LTS   9.0.0.7
  v9.1 CD    9.1.3
  v9.1 LTS   9.1.0.3
  
  The latest available maintenance can be obtained from
  'WebSphere MQ Recommended Fixes'
  http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006037
  
  If the maintenance level is not yet available information on
  its planned availability can be found in 'WebSphere MQ
  Planned Maintenance Release Dates'
  http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006309
  ---------------------------------------------------------------
  

Temporary fix

Comments

APAR Information

• 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

  IBM MQ BASE MP

• Fixed component ID

  5724H7251

Applicable component levels