IV45924: HPR HANG DUE TO HOST GAP MESSAGE PACKET BEING DROPPED IN THE NETWORK

Communications Server for AIX, Version 6.3 -- Last PTFs

APAR status

• Closed as program error.

Error description

• A remote VTAM host has fixed pacing window size of 1.  As the
  VTAM attempts to send data which needs more than 1 RU to
  complete it requests another pacing window to complete its
  transfer with a pacing indicator.  CS/AIX sends an IPR with a
  status request (SR) with RASAP set.  The remote VTAM host
  responds with a status with the Received Sequence Number (RSN)
  set to our BSN before the IPR, indicating that the remote host
  never received the IPR.  However, the session continues to hang
  as CS/AIX never attempts to retransmit the IPR packet.
  

Local fix

Problem summary

• USERS AFFECTED:
  All users of HPR
  
  PROBLEM SUMMARY:
  Directly connected HPR/IP connection can hang up if packets are
  lost in both directions in quick succession and there is no
  other activity on the connection to drive retries. The gap
  detected packet from the mainframe was dropped in the network.
  

Problem conclusion

• Code has been changed to restart the short request timer when a
  status packet is received which has an implicit gap detected,
  i.e. the partner system indicates that it has not seen the last
  system sequence number transmitted but has not reported the gap
  detected yet (it is waiting for the refifo timer to expire).
  

Temporary fix

• sna_v5router64
  

Comments

APAR Information

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

  IV41297

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

Fix information

• Fixed component name

  CS AIX V6.X

• Fixed component ID

  5765E5100

Applicable component levels

• R631 PSY U860529

     UP13/09/18 I 1000