User IDs checked for IMS connections

The user IDs checked for IMS connections depend on whether one or two checks are to be performed, and whether an alternate user ID is specified. If a second user ID is checked, it depends on the type of dependent region and on which user IDs are available.

Table 1. User ID checking against profile name for IMS-type user IDs
Alternate user ID specified on open?	hlq.ALTERNATE.USER.userid profile	hlq.CONTEXT.queuename profile	hlq.resourcename profile
*No, 1 check*	-	REG	REG
*No, 2 checks*	-	REG+SEC	REG+SEC
*Yes, 1 check*	REG	REG	REG
*Yes, 2 checks*	REG+SEC	REG+SEC	REG+ALT

Key:

ALT: Alternate user ID.
REG: The user ID is normally set through the STARTED class or the started procedures table or, if IMS is running, from a submitted job, by the USER JCL parameter.
SEC: The second user ID is associated with the work being done in a dependent region. It is determined according to Table 2.

Table 2. How the second user ID is determined for the IMS connection
Types of dependent region	Hierarchy for determining the second user ID
BMP message driven and successful GET UNIQUE issued. IFP and GET UNIQUE issued. MPP.	User ID associated with the IMS transaction if the user is signed on. LTERM name if available. PSBNAME.
BMP message driven and successful GET UNIQUE not issued. BMP not message driven. IFP and GET UNIQUE not issued.	User ID associated with the IMS dependent region address space if this is not all blanks or all zeros. PSBNAME.