Activation of the PU can be either DLUR-initiated or DLUS-initiated. For DLUR-initiated PU activation, no system definition is required. Instead, the dynamic switched definition facility is used to dynamically define the PU. For information about this facility, see the z/OS Communications Server: SNA Network Implementation Guide. Alternatively, you can code a switched major node for the DLUR-supported PU. For instance, where the DLUR is in Communications Manager/2, you can code a switched major node that specifies IDBLK and IDNUM values that, when combined, match the value specified for NODE_ID in the Communications Manager/2 DEFINE_DEPENDENT_LU_SERVER definition statement.