Because there is no resource hierarchy among major nodes, any NCP major node can be deactivated at any time. The deactivation of an NCP does not cause VTAM® to deactivate any other NCP. However, there are physical dependencies you must consider. When an NCP is deactivated, all paths using the NCP are also deactivated. Therefore, any NCPs that are link-attached to the NCP being deactivated are rendered inoperative. In addition, deactivation of an NCP or a cross-subarea link or link station can have significant and disruptive effects on other subarea nodes.

To avoid disrupting sessions, you need to be concerned about the status of cross-subarea links and link stations after an NCP deactivation.

Same-domain links are governed by the following rule: when you enter a VARY INACT command for an NCP, VTAM automatically deactivates any link or link station in an adjacent subarea node that was automatically activated when the NCP was activated. VTAM does not perform these automatic deactivations if you activate links and link stations directly or indirectly.