CLOSE LINK command: Model 204 non-CNOS intersystem link

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Summary

Privileges
User 0, system administrator, system manager
Function
Disable an opened link.

Syntax

CLOSE LINK linkname [FORCE | IMMD | ABANDON]

Where:

  • linkname is the link specified on the DEFINE LINK command.

  • FORCE specifies that any conversations using the link are ended immediately, the SNA Communications Server ACB is closed, and all internal buffers and control blocks are released. If a more gradual termination of network activities is desired, refer to STOP command: Stopping a Horizon or Model 204 SQL link or processgroup.

  • IMMD specifies that the ACB for the link in question should be closed immediately. By closing the ACB inline, you can significantly speed up CLOSE LINK processing, because it supplanted the scheduling of the CLOSE ACB on a Horizon pseudo subtask.

  • ABANDON specifies that if the FORCE argument has not successfully closed the link, because there are VTAM requests outstanding, ABANDON processing will deactivate the link and reclaim as much storage as possible. You can reestablish communication using an alternate link.

Usage notes

CLOSE LINK FORCE disables the link specified in a DEFINE LINK command for any Model 204 non-CNOS intersystem link except TPROCESS, Transfer Control, and UL/DB2. Conversations using the link are ended immediately and no new ones can start. The SNA Communications Server ACB or CRAM or IUCV channel is closed, and all internal resources, buffers, and control blocks are released.

If the link you are closing supports a combination of CNOS and non-CNOS sessions, the CLOSE LINK without the FORCE parameter drains the conversations on CNOS sessions first, and then it forces the conversations on non-CNOS sessions.

The CLOSE LINK ABANDON command eliminates the need to bring down an Online if a VTAM link fails, allowing the possibility to establish communications using an alternate link. (It is sometimes possible to open a new Horizon VTAM link to replace the abandoned link, using the OPEN LINK command with the REPLACE keyword. For details, see OPEN LINK command.)

The CLOSE LINK command is not required at shutdown; an implicit CLOSE LINK is performed during Model 204 termination.