ISO 17261:2012 describes the conceptual and logical architecture for automatic vehicle and equipment identification (AVI/AEI) and supporting services in an intermodal/multimodal environment. It presents a high level view of AEI intermodal and multimodal system architecture, and describes the key sub systems, their associated interfaces and interactions and how they fit into system wide functions such as management, security and information flow. ISO 17261:2012 identifies the context of intermodal/multimodal AEI within the overall AVI/AEI context and key external inter-dependencies and interfaces to the intermodal/multimodal sector IT infrastructure. These include interfaces to the external and internal users of the intermodal/multimodal system services and their associated IT systems, interfaces to intermodal/multimodal management systems, existing intermodal/multimodal networks and system operations, and specifically interfaces to item identification and the domain of JTC 1/SC 31, item logistics International Standards. As an architecture it is designed to be complementary and interlocking to that domain. ISO 17261:2012 is intended to be complementary and consistent with the work of ISO/TC 104, Freight containers. It extends the conceptual and communication AVI architecture determined in ISO 14814 and is neither frequency nor air interface protocol specific. It provides maximum interoperability, has a high population capability, and provides the possibility of upwards migration to more capable systems. It does not include the air interface nor any implementation aspect, only the reference architectures. Subsequent International Standards define data structures for general AVI/AEI and for specific sectors of application.