EPCglobal’s adoption of tag specifications is paralleled by the construction of a vast item tracking infrastructure. The EPC Network is designed to allow RFID users to share information about the condition and transit of goods as they move through the supply chain. The system allows trading partners to share some or all data gathered by automatic identification, securely and in real time.
The Electronic Product Code (EPC) is a 96-bit code that indicates a manufacturer, class and unique serial number. A class is a ‘type’ of item as defined by its manufacturer. An EPC code is unique and represents a unit or group.
The ability to create official EPCs is delegated by EPCglobal, and requires a “subscription” (membership) with the organization. Subscription pricing is based on a company’s revenue and the number of EPCs it plans to assign. According to EPCglobal’s Senior Director of Public Relations Jack Grasso, large companies have no pricing advantage. There are no guidelines for who can or cannot join EPCglobal and thus produce EPC codes, although Mr. Grasso assured RFID News that reasonable limits do apply. An EPCglobal subscription can range into the hundreds of thousands of dollars for large organizations.
The EPC is the basic unit used to querying the following services. Each exists at a different level of abstraction. The highest level, ONS, essentially provides a map to other resources, both in and outside the EPC Network.
The Object Naming Service (ONS) is a directory service that provides references to resources specific to an EPC. The service is similar to the Internet’s Domain Name System (DNS) that maps a domain name to a network address of a computer.
The ONS operates as a hierarchy. The topmost level, run by VeriSign and called the “Root ONS” is a directory of manufacturers. After reaching this level, a request would be forwarded to the appropriate manufacturer’s “Local ONS,” a directory of that manufacturer’s products. This directory offers resources specific to EPCs, such as EPC-IS, Discovery Services, trust services, ERP systems, PIM’s, or GDSN Datapools. The ONS will only be implemented by manufacturers, who will likely buy local ONS hosting services from VeriSign or one of its competitors.
The EPC-IS provides product information such as an item’s manufacture date or point of origin.
The EPC Information Service (EPC-IS) offers information specific to individual EPCs. It is accessible through several methods, such as a web service or serialized data stream, although not necessarily a particular method. An EPC may have information about it stored at more than one EPC-IS.
While ONS is the central access point for information on an EPC, it only references other information sources. The EPC-IS provides serial-number specific information. While the manufacturer controls ONS records, it would use EPC-IS to provide real-time information specific to each of its tagged products.
Any party can create an EPC-IS. Distributors and retailers might use EPC-IS to supplement the manufacturer’s EPC-IS.
EPC Discovery Service
The EPC Discovery Service allows an interested party to find records internal to the EPC Network relating to a specific item, but spanning companies or divisions.
The EPC Discovery Service is a comprehensive directory of EPC-IS instances. If an EPC-IS contains information about an EPC, it registers itself with the EPC Discovery Service. Querying the Discovery Service with an EPC provides a list of all EPC-IS instances that contain information about that EPC.
EPC Trust Services
EPC Trust Services allow owners of an EPC-IS instance to regulate access. They use a hierarchy of trusted parties and digital certificates to verify a network user’s identity at run-time.
Tight access control of an EPC-IS is crucial to the EPC Network. Inventory information is highly confidential, yet has enormous utility to an organization’s customers or suppliers.
The coordinating components of the EPC Network give manufacturers, distributors and retailers unprecedented inventory visibility. While most contemporary RFID systems are not yet a part of the EPC Network, the economic necessity of sharing vital inventory information make broad adoption very likely.
More information on the EPC Network is available at VeriSign’s website.