An NCP major node, which is a type 4 subarea node, is defined by filing NCP definition statements in the VTAM® definition library. The name under which the major node is filed must match the NCP load module name on the NEWNAME operand of the BUILD definition statement.

Additional information required by VTAM to communicate with the NCP and its attached devices is provided to VTAM by coding VTAM-only definition statements and VTAM-only operands on NCP definition statements. The VTAM-only definition statements and operands must appear in the NCP definition statements that define this NCP to VTAM, even though they provide no information to the NCP. If VTAM-only operands are changed or replaced, no new NCP generation is required.