If LINK1 and LINKSTA1 are active when NCP2 is deactivated, LINK1 and LINKSTA1 are automatically deactivated, unless you directly or indirectly activate them.

Therefore, if the link between NCP1 and NCP2 continues to carry session traffic after NCP2 is deactivated by HOST1, you should ensure that LINK1 and LINKSTA1 are directly or indirectly activated. This can be verified by entering a DISPLAY command for the link or link station (a DISPLAY of either resource displays the status of both). As a result, the only path available for session traffic to flow using the link between NCP1 and NCP2, given that HOST1 is deactivated, is from NCP1 to NCP2 to NCP3 to HOST2 for PLUs in the host. If PU type 2.1 nodes are attached to NCP1, NCP2, or NCP3, that link can also be used for session traffic.

The order in which the NCPs are deactivated determines how a VTAM® domain contracts. The deactivation of an NCP by a VTAM host removes that NCP from the domain of that host. After an NCP is deactivated in a domain, all links leading to it are considered cross-domain links. During an NCP deactivation, then, same-domain links might become cross-domain links. If two or more NCPs are deactivated simultaneously (except as a result of a HALT command; see Halting VTAM), the time when the change occurs is unpredictable, and it might be difficult to apply the previously described rules for not disrupting sessions. Unless these rules are followed so all links have the same final disposition (active or inactive), regardless of which rule applies, do not deactivate the NCPs simultaneously.