This part of ISO/IEC 15045 specifies a gateway architecture that provides an interconnection between one or more Wide Area Networks (WANs) and one or more Home Area Networks (HANs). This standard is not needed for a"simple gateway" linking one WAN to one HAN where there is no intention of future expansion, as illustrated in Figure 1. The scope of this standard applies to a"distributed gateway," as illustrated in Figure 1 and is also referred to in ISO/IEC 15045-1 as the Complex Modular Gateway. Also, this standard specifies how separate gateways in a single house can interoperate to provide co-ordinated functions.