PI69975: FORMER SYSPLEX DISTRIBUTOR DISCARDS PACKETS IMMEDIATELY AFTER V TCPIP,,SYSPLEX,DEACTIVATE,DVIPA=X.X.X.X COMPLETES

APAR status

• Closed as fixed if next.

Error description

• A sysplex distributor gracefully surrendered a DVIPA to a
  backup distributor when processing a deactivate DVIPA command
  (V TCPIP,,SYSPLEX,DEACTIVATE,DVIPA=x.x.x.x). Packets destined
  for the DVIPA address continued to arrive at the original
  distributor and were discarded with discard code 4167
  (IP_NO_FWD) until the network routers were updated with the new
  DVIPA distributor information.
  The delay in the network update and subsequent packet discarding
  may cause delays on connections due to retransmits or depending
  on the applications tolerance to delays the termination of
  connections.
  
  Verification Steps:
  A packet trace at the original distributor shows that packets
  arriving after the deactivate DVIPA completed were discarded
  with a discard code 4167 (IP_NO_FWD).
  

Local fix

• Enable datagram forwarding by specifying DATAGRAMFWD in the
  IPCONFIG statement to allow packets to be forwarded to the new
  DVIPA distributor.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * All users of the IBM Communications Server                   *
  * for z/OS Version 2 Releases 1, 2 and 3.                      *
  * IP:  Sysplex Distributor                                     *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * Packets directed to a DVIPA on a sysplex distributor that    *
  * recently gave up distributing the DVIPA will be discarded.   *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * FIN                                                          *
  ****************************************************************
  A V TCPIP,,SYSPLEX,DEACTIVATE,DVIPA=x.x.x.x command was issued
  at a sysplex distributor to move a distributed DVIPA from the
  original sysplex distributor to the backup sysplex distributor.
  Packets may continue to be directed to the original sysplex
  distributor until the network routers are updated,. The original
  distributor will discard the packets. Usually the packets will
  be retransmitted and after router updates they will eventually
  be directed to the new sysplex distributor. However different
  applications may be less tolerant of the delays associated with
  the retransmissions and cause the associated connections to be
  terminated.
  

Problem conclusion

Temporary fix

Comments

• The solution for this APAR is included in CS for zOS Version 2
  Release 4.
  
  This APAR is being closed FIN (Fixed If Next) with concurrence
  
  from the submitting customer. This means that a fix to this
  
  APAR is expected to be delivered from IBM in a release (if any)
  
  to be available within the next 36 months.
  

APAR Information

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

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

Fix information

Applicable component levels