IMS Connectivity in an On Demand Environment: A Practical Guide to IMS Connectivity

Chapter 15. IMS Connect client diagnostics 303

15.3.1 Duplicate clientID (reason code 56)

This error occurs when you send IMS Connect an interaction on a given port using a clientID

that is already in use on that port. There can be several reasons that this can occur:

 You are executing two concurrent interactions using the same clientID. This can happen

when you are running more than one instance of an application in the same or different

machines, or in cloned environments, especially if you are using dedicated persistent

sockets, which require user-specified clientIDs, with IMS Connector for Java.

You must ensure that the same clientID is not associated with more than one connection

to a given IMS Connect port. In particular, it is not possible to both send transactions and

recover asynchronous output messages (RESUME TPIPE) on different connections to the

same IMS Connect port using the same clientID at the same time. For example, if you are

executing a receive asynchronous output interaction (RESUME TPIPE) using clientID

12345abc on a socket connected to PORT 5678 of IMS Connect ICON01, you are not able

to submit transaction requests using the clientID 12345abc on another socket connected

to PORT 5678 of IMS Connect ICON01.

Note that it is possible to use the same clientID on two different sockets connected to the

same IMS Connect, provided that the sockets are connected to different ports on that IMS

Connect.

 You are executing an interaction with a clientID that is the same as that used by another

interaction that ended as a result of a socket timeout. If this new interaction is received by

IMS Connect while IMS Connect is still waiting for a response from IMS for the original

interaction that received the socket timeout, a duplicate clientID error might occur.

This can happen if you set the socket timeout to a value that is less than the timeout set by

the IRM_TIMER (or ExecutionTimeout in the case of IMS Connector for Java) or the IMS

Connect default timeout set in the HWSCFGxx member if that is the timeout being used

for the original interaction. IMS Connect is not aware that the original socket has been

disconnected as a result of the socket timeout until it does a subsequent read on that

socket, so it would consider the original socket still active, even though that socket has

already been disconnected from the client end. Figure 15-2 on page 304 shows the

sequence of events that lead to this problem. After you get to this situation, you will receive

DUPECLNT errors until:

– The IRM_TIMER expires on the IMS Connect side.

– You issue a STOPCLNT command to kill the client on the IMS Connect side. A

DELETE PORT command also kills the client, but we do not recommend this, because

it disables that port for all clients.

Example 15-7 shows the message IMS Connect writes in the system log when a

DUPECLNT occurs.

Example 15-7 IMS Connect JES2 DUPECLNT error message

HWSS0742W MESSAGE FAILED, ORIGIN=7003 _CLIENT01 TO DESTID=IMSG ; R=8, S=DUPECLNT,

M=SRE4