Console Automation Recovery and the Defer Host Disconnect (DHD) Option

Document ID : KB000055434
Last Modified Date : 14/02/2018
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With Unicenter Automation Point r11.1, you can establish direct MCS console connections to an Open Systems Adapter-Express Integrated console Controller (OSA-ICC) using native protocol support for TN3270E. This article describes how the OSA-ICC session parameter, Defer Host Disconnect (DHD), impacts Unicenter Automation Point's MCS console automation when the OSA-ICC server detects a TN3270E client (Unicenter Automation Point MCS console session) disconnect.

The DHD option is primarily intended for use by z/OS operator console sessions. When DHD is enabled, the OSA-ICC controller defers reporting the console disconnect status to z/OS for a designated period.

If a client reconnects before the designated period times out, the OSA-ICC controller automatically simulates the 3270 CLEAR key, triggering z/OS to reformat the console screen and to continue sending console messages. This makes it unnecessary for an operator to have to manually vary the MCS console device back to ONLINE status. The DHD option is described in detail in IBM Redbook, OSA-Express Integrated Console Controller Implementation Guide. See www.ibm.com/redbooks/

A TN3270E console client disconnect occurs in the following situations:

  • The Unicenter Automation Point MCS console session is stopped and restarted. This occurs every time the Automation Point Desktop is recycled, the Unicenter Automation Point server is rebooted, or a power-on-reset is issued for the MCS console session.

  • A network connection is momentarily down or becomes unavailable. Unicenter Automation Point automatically responds to unexpected network connection errors by periodically attempting to reconnect.

When a Unicenter Automation Point MCS console session is disconnected for any of the reasons mentioned above, the OSA-ICC server handles the subsequent reconnect according to the settings configured for the DHD option. Once reconnected, Unicenter Automation Point resumes MCS console automation (when the console session is in a recognized state), enabling Unicenter Automation Point MCS session scripts to control the console session.

Upon session reconnect, operator intervention may be necessary to recover the MCS console and restart Unicenter Automation Point MCS console automation. The following scenarios help you determine how to adjust your site automation, if necessary:

  • DHD disabled: Once a Unicenter Automation Point MCS console session reconnects, the session window displays the OSA-ICC connection status screen. Before MCS message traffic resumes, each corresponding MCS console device must be manually varied to ONLINE status. Once the MCS console is active, Unicenter Automation Point MCS console automation is automatically restarted in the usual manner.

  • DHD enabled (reconnect before user-defined deferment expires): Unicenter Automation Point MCS console sessions that successfully reconnect within the user-specified deferment time can resume automation without further operator intervention. See *Note below.

  • DHD enabled (reconnect after user-defined deferment expires): Unicenter Automation Point MCS console sessions that reconnect after the user-specified deferment time expires displays the OSA-ICC connection status. The corresponding MCS console device must be manually varied to ONLINE status before MCS message traffic resumes and Unicenter Automation Point console automation can automatically restart. See *Note below.

  • DHD enabled with no deferment timeout: Unicenter Automation Point MCS console sessions that successfully reconnect at any time can resume automation without further operator intervention. See *Note below.

*Note: Be aware that while the UnicenterAutomation Point MCS console session is disconnected, the OSA-ICC controller continues to allow z/OS to direct messages to the MCS console until the deferred disconnect period expires. While disconnected, those messages are not monitored by Unicenter Automation Point and therefore are not automated.