Path of message issued from a local processor

Figure 1. Simplified path of a message issued from a local processor

When a message originates A from a local processor, MPF B can alter the message's routing and presentation characteristics.
Next, MVS™ places the message on the subsystem interface (SSI). The SSI C is the portion of the system on which other subsystems, such as JES3, can access and alter the path of a message.
While on the SSI, JES3 (IATUX57 and MSGROUTE processing specifically) can modify the message's original routing information D . JES3 calls exit 69 to process the message. The message is sent to the global processor in a staging area E if the JES3 global and local are below a minimum release level of HJS7705 and any one of the following conditions exist:
- The message needs to be logged in the joblog data set (JESMSGLG).
- The message requires special processing, for example, it is a message related to a JES-managed device.
- Exit 69 indicates the message needs further processing.
Note: If the JES3 global and local are BELOW a minimum release level of HJS7705 and exit 69 indicates that the message should be sent to the global address space, the message is sent to exit 70. When the JES3 global and local are at a minimum release level of HJS7705, the message is NOT sent to the JES3 global, but processed on the user's address space.
The message is also placed back on the SSI for processing by an automation package F if present, or for display on MCS consoles.
In addition to JES3 processing G , MCS routes a message for presentation to consoles attached to other systems in the sysplex. MCS routes a message only if there is an active receiver (for example, a console eligible to receive the message) on the system.
The message is placed on the SSI on all systems that receive the message. MPF processing takes place only on the originating system. The GLOBMPF parameter on the JES3 CONSTD initialization statement can be used to indicate MPF should be invoked on the global processor for all messages routed to the global processor regardless of the originating system.