Registering independent LUs

Because the characteristics of an independent LU and of the node on which it resides are not recorded by VTAM®, it is difficult to determine the appropriate level of registration for all cases. Therefore, independent LUs are not registered by default because registration of the same resource from multiple nodes can result in the generation of alerts in the APPN network or sub-optimal routing of LU-LU sessions.

However, if an independent LU is owned by a LEN node (that is not acting as an end node in the network), the registration of the independent LU is recommended. Because LEN nodes cannot participate in APPN searches, their LUs cannot be found unless the LUs are defined to an APPN node connected to the LEN node. In this case, you can code the REGISTER operand on the CDRSC or LU definition to register the independent LU to the network node server, or to the network node server and the central directory server. If a large group of independent LUs requires registration, the REGISTER operand can be specified on a higher level definition statement to take advantage of the sift-down effect.

Note: Do not specify the REGISTER operand on CDRSC statements on which the CPNAME operand has been coded because the CPNAME operand indicates that the independent LU resides on another APPN node that will be responsible for registering the LU. If the two operands are coded on the same CDRSC statement, either explicitly or by the sift-down effect, the REGISTER operand will default to NO and be ignored.

If you dynamically change an independent LU, the rules cited in Rules for multiple definition of resources are followed.