Here is my understanding:
The PDL timeout only has to do with when a message is received and it is not complete (this can happen if the TCP packets are broken up). PDL will wait a certain length of time for the rest of the message to appear.
Typically the PDL timeout is not involved in the situation you are experiencing.
When a message is sent out of the outbound thread Cloverleaf(R) will wait for the prescribed time for a response (if the ‘Wait replies’ switch is set and the timeout time is set).
IF the ‘Outbound only’ box is checked, Cloverleaf(R) throws an ‘await reply’ switch after the message is sent. That switch being thrown indicates to Cloverleaf(R) that the next mesage received on the thread is to be treated as a reply (the appropriate metadata field gets set to REPLY not DATA).
IF the ‘Outbound Only’ box is not checked, Cloverleaf(R) does not throw that switch and all messages received are treated as DATA. That can still work but now it is your responsibility to provide appropriate Tcl procedure(s) to interpret the actual message and determine yourself whether the message is a reply or data.
In most situations the outbound thread is intended to be ‘broadcast’ in nature. That is the messages go out and the only thing expected back inbound is an acknowledgment the message was received so message pacing can be controlled.
There are cases wherein asynchronous message deliver technique (Query/Response paradigm) is attempted over a single port that the situation is (typically) a Query message is sent; an acknowledgment is received; but at the same time and at any time a response to the current or previous Query is received. One of the inbound mesages is an acknowledgment and the other is a requested response to a query. The acknowledgment has to be treatred properly for message pacing, but the Response has to be recognized as well so that it can be routed and potentially translated to the original Querying system. In this case the ‘Outbound Only’ box should not be checked – and special Tcl coding needs to occur to handle the various types of inbound messages appropriately.
I should mention another method for achieving asynchronous message delivery. That is to have the outbound thread for the Queries (and their acknowledgments) set up in the normal outbound thread fashoin (Outbound only checked). A separate inbound thread for the asynchronous Responses to the Queries. This is set up as a normal inbound thread. For Asycnhronous message delivery (Query/Response), I personally favor this method.
I do not think you should necessarily lose any messages if you do not have the ‘Outbound only’ checked, but since I can’t say I have ever run for very long with that situation, I really have not paid attention to the recovery aspects.
If I accidently set up an outbound thread with the incorrect setting, I detect it early in the testing or configuration process, correct it and move on.
Suffice to say if you do not expect actual inbound data on your outbound thread, set the ‘Outbound only’ on.
If my interpretation of the process is off , I am sure someone will offer corrections.