PI15839: SERVER USING FRCA WILL OCCASIONALLY NOT RESPOND TO LOCAL CLIENT

Obtain the fix for this APAR.

APAR status

• Closed as unreproducible in next release.

Error description

• .
  The web server is setup to use the Fast Response Cache
  Accelerator (EnableFRCA On is specified in the httpd.conf file).
  When clients are running on the same system, occasionally the
  first (only) request sent on a connection will not get a
  response from the server.  The server's logs will not show any
  information for the affected connections.
                                                                 .
  

Local fix

• .
  Use one of the following options to avoid this problem:
  
   - Disable FRCA on this server.
  
        EnableFRCA Off
  
   - Enable a packet trace, even if filters prevent any packets
     from being recorded:
  
        VARY TCPIP,tcpipname,PKKTRACE,ON,PROT=240
  
   - The following command may be entered every time TCPIP is
     recycled:
  
        MODIFY tcpipname,FRLSOFF
  
  
  
  Other symptoms:
  
  A SYSTCPIP CTRACE with OPTIONS=(AFP,TCP) will show an 'FrLS
  exit' record for the client side of the affected connection
  before the 'Afpa Add Connection Entry' record for the server
  side of the connection.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: All users of the Communications Server for   *
  *                 z/OS Version 1 Release 13 IP                 *
  ****************************************************************
  * PROBLEM DESCRIPTION: TCP/IP client connections to Web Server *
  *                      using FRCA time out.                    *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  TCP connection times out attempting to connect to a Web Server
  using FRCA. This occurs when the client and server are on the
  same TCP/IP stack. In this scenario, the Faster Local Sockets
  function may be employed on the first write of data before the
  connection has transitioned to use FRCA. This invalid scenario
  should be protected with locks. However, the client side does
  not obtain the correct tcb lock preventing the necessary
  synchronization.
  +-------------------------------------------------------------+
  + Please check our Communications Server for OS/390 homepages +
  + for common networking tips and fixes.  The URL for these    +
  + homepages can be found in Informational APAR II11334.       +
  +-------------------------------------------------------------+
  

Problem conclusion

Temporary fix

Comments

• EZBTCFWR and EZBT6FWR have been changed to first check if the
  connection is still on the server's accept queue before
  obtaining the appropriate tcb lock.
  This APAR is a logical route of defect 20229.
  

APAR Information

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

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

  UI17335 PI17154

Modules/Macros

• EZBTCFWR EZBT6FWR ITTIMER
  

Fix information

• Fixed component name

  TCP/IP V3 MVS

• Fixed component ID

  5655HAL00

Applicable component levels

• R1D0 PSY UI17335

     UP14/05/31 P F405

Fix is available

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