To interconnect subarea networks, at least one gateway NCP is required. The gateway NCP performs the address translation necessary for cross-network session traffic.

To illustrate how a gateway NCP is defined, consider NCP A03 in the network depicted in Figure 1. The NCP major node for A03, as shown in Defining a channel-attached NCP, specifies the GWCTL and NETID operands on the PCCU definition statements, defining the NCP as a gateway NCP. The NETID operand on the BUILD definition statement specifies NETA as A03's native network. The NETWORK definition statement defines NETB as the network identifier of the non-native network (the network attached to the gateway NCP). The GWNAU definition statements that follow the NETWORK statement define cross-network CDRMs to the non-native network. Finally, the PATH definition statements that follow those GWNAU statements define routes for NETB that originate in the gateway NCP subarea.

For sample CDRM major nodes used in SNA network interconnection, see Connecting multiple networks using SNA network interconnection.