This unsolicited message is issued when HPR detects that data flow for an RTP pipe stalled. The data flow is considered stalled because the RTP partner requested retransmission of at least one NLP, but the request cannot be honored. It might be an indication of either a device problem or an internal software problem.
Tip: It is not unusual for a stall to be detected on an RTP pipe that is in the process of pathswitching.
puname is the name of the HPR PU.
cpname is the name of the CP at the other end of the pipe.
HPR attempts to make an internal copy of the NLPs causing the data flow stall (known as NLP recovery). If the copy is successful the recovered NLPs are retransmitted. If the stall persists, IST1956I is issued every 30 seconds until the stall is alleviated.
The operator can use the DISPLAY NET,ID=puname or DISPLAY NET,RTPS,STALL=YES commands to monitor stalled RTP pipes.
If the data flow stall persists, issue VARY procname,INACT,ID=puname,TYPE=FORCE to deactivate the HPR PU and end the hung sessions.
If you want VTAM® to automatically deactivate stalled RTP pipes after a specified amount of time, use the HPRSTALL start option. See the HPRSTALL start option information in z/OS Communications Server: SNA Resource Definition Reference.
If data flow stalls are prevalent and persistent, contact VTAM support for instructions about gathering documentation for problem determination.
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