gtps2m2hACF/SNA Data Communications Reference

Activating and Deactivating Cross-Domain Resource Managers

In the PU 5 environment, a CDRM to CDRM session must be established before resources in a TPF domain can communicate with resources in another domain. Here, the CDRMs work in tandem to activate, maintain, and terminate sessions between resources. The network address of the T5 SNA Network Interconnection (SNI) gateway CDRM is not defined to the TPF system until the session is activated. Therefore, the TPF system is unaware of the path the session will take. This enables the TPF system to dynamically discover the network address of the CDRM, which allows an alternate path to be used if the CDRM-CDRM session breaks.

Define to the TPF system each CDRM that can connect to the TPF system as a T5 node. See Defining SNA Resources to the TPF System for more information about defining CDRM resources to the TPF system.

When the TPF system is connected to a VTAM system using both PU 5 links through SNI NCPs and APPN links, you must define an alias name for the CDRM in VTAM. See SNI and APPN Considerations for more information.

A CDRM-CDRM session over a channel-to-channel link can be activated by the operator of either domain.

The operator of either domain can deactivate the CDRM-CDRM session. A deactivation request between domains is called a cross-domain takedown (CDTAKED). Cross-domain takedown requests include:

CDTAKED orderly:
Equivalent to TPF orderly deactivation.

CDTAKED forced:
Equivalent to TPF immediate deactivation.

CDTAKED cleanup:
Equivalent to TPF forced deactivation.

Either domain manager can perform two types of deactivation:

Support of nondisruptive CDRM inactivation and reactivation is specified during CDRM session establishment. Control vector 6 in the ACTCDRM request and response contains this information. Nondisruptive inactivation can be performed regardless of whether the adjacent SSCP supports nondisruptive inactivation.

When the adjacent SSCP supports nondisruptive inactivation, the same sequence of PIUs are used to perform both disruptive and nondisruptive inactivation. The only differences between nondisruptive and disruptive inactivation are the type of cross-domain takedown (CDTAKED) and deactivate CDRM (DACTCDRM) commands and the status of the LU-LU sessions after the inactivation is completed.

Note:
During nondisruptive CDRM inactivation, the associated LU-LU sessions which remained in session across the inactivation are disassociated from their owning CDRM. The consequence of this disassociation is the LU-LU sessions are not reassociated with the CDRM session when it is re-established. In order to inactivate the LU-LU sessions that survived a nondisruptive CDRM inactivation, an inactivation request must be specified on either NAU involved in the LU-LU session.

When the adjacent SSCP does not support nondisruptive inactivation, TPF treats the nondisruptive inactivation request as a session outage notification (SON). The operator should be aware that only the LU-LU sessions that support SON remain active across the inactivation. Both a nondisruptive immediate and forced inactivation of a CDRM that does not support nondisruptive inactivation results in SON, with only a flow of a single PIU (a DACTCDRM type 3). A nondisruptive immediate inactivation is escalated to a forced inactivation to perform SON.

Note:
When TPF initiates a nondisruptive inactivation, TPF always interprets the first ACTCDRM request from the remote SSCP as an attempt to automatically recover the CDRM session. TPF then sends an 0858 negative response to the ACTCDRM request. If an automatic recovery was not intended, the operator can reissue the CDRM activation request, and TPF completes the CDRM reactivation successfully.

Once the TPF domain manager is in session with another domain manager, resources within the domains can communicate. The ZNETW command activates and deactivates cross-domain resources.

Cross-domain resources are also deactivated if:

Path malfunctions can occur in the communication line, NCP, 37x5, and/or owning CDRM.

Activation of a CDRM is non-disruptive to any ongoing cross-domain LU-LU sessions that may exist at the time of the activation. This feature enables a VTAM CMC to restart a failed CDRM-CDRM session without affecting any cross-domain sessions that survived the failure.