The need for interoperability is very clear in end-to-end supply chain applications where goods move through dozens of different trading partners and businesses, each with potentially unique implementations of RFID infrastructure and application requirements. Thus, the need to have a common means of data formatting, processing, and exchange that helps these unique systems to interoperate becomes obvious. A standards organization called EPCglobal helps address this need through creation of EPCglobal standards. In the following sections, we describe the key components that enable the creation of RFID systems that are EPCglobal standards-compliant. The components are collectively referred to as the EPCglobal Network. In Chapter 4, we discuss key EPCglobal and other standards that have been ratified or are under consideration. Because EPCglobal standards are evolving rapidly, we recommend that you consult the EPCglobal Web site (www.epcglobalinc.org) to obtain information on the latest advancements and developments related to these standards or ask your vendors for the latest update.
Electronic Product Code (EPC)
EPC is a numbering scheme that allows assignment of a unique identifier to any physical object. It can be regarded as the next generation Universal Product Code (UPC), which is used on most products today. EPC enables the means to assign a unique identifier to each item, thus allowing every item to be uniquely identified. The current format of EPC type I data that allows this unique identification includes the following fields (see Figure 3.8):
Figure 3.8. EPC Numbering Format
This 96-bit EPC specification provides unique identifiers for 268 million companies. Each company can have 16 million object classes, with 68 billion serial numbers in each class.
The ID System
The ID system refers to the tag and reader components. EPC codes are stored on EPC tags that are read by EPC readers. This is the area where significant EPCglobal standards activities are focused today. Currently, several standards describe tag formats, functionality, and tag-reader communication for different types of tags (see Chapter 4 for details). The ultimate goal is to drive standards that provide common means for tags and readers from all compliant vendors to function similarly and communicate seamlessly.
In a supply chain environment where readers are picking up a nearly constant stream of EPCs, managing the data is a significant task. The EPC Middleware (sometimes known by its old name, the Savant) is responsible for managing EPC data flow between readers within an enterprise and the enterprise's existing application software. Similar to what we described earlier as RFID middleware, the EPC Middleware functions consist of collection, processing, filtering, and aggregation of data.
Object Name Service (ONS)
The ONS matches the EPC of a product to information about that product. When the EPC Middleware receives EPC data, it can query an ONS server to find out where more detailed product information is stored.
This system has been modeled after the highly scalable, reliable, and high-performance Domain Name System (DNS) system used in the Internet. When using the Internet, you can provide a URL to a DNS server and expect to receive the associated IP address. Because it is anticipated that RFID will scale to identifying trillions of products from thousands of companies using public network infrastructure, DNS design concepts were used in the design of ONS.
EPC Information Services (EPCIS)
The EPCIS component specifies the services and interfaces that are necessary to facilitate data exchange among trading partners' applications across an entire supply chain. A key feature consists of a central repository of EPC data that is shared and updated by supply chain trading partners globally. When fully implemented and adopted, EPCIS will provide the infrastructure necessary to accelerate true end-to-end supply chain integration.
For additional technical details on the EPCglobal network architecture, see Appendix B, the white paper titled "The Sun EPC Network Architecture." This paper describes a typical system architecture based on the EPCglobal specifications. It demonstrates the way in which some of the key EPCglobal components come together to form the basis for building a large-scale supply chain application.