RFID readers route tag traffic

At every turn, networks must handle additional traffic from new sources. One of the latest and soon-to-rise sources of increased network traffic arises from the implementation of radio frequency identification , which is being used for needs such as supply-chain management, tracking airport baggage and prescription medication shipments. These examples alone suggest a growing volume of TCP/IP network traffic and data.

While conventional RFID readers were essentially data radios, today's enterprise-grade RFID tag readers - created specifically for electronic product code (EPC) usage - have been designed to be full-fledged network devices that can support mission-critical operations. In addition to managing a dynamic population of tags, then routing data into networks, databases and business applications, these RFID readers have to speak TCP/IP natively and fully support standard network technologies such as DHCP, User Datagram Protocol (UDP)/IP over Ethernet, 802.11x, HTTP, SNMP and remote upgrades.

This design lets RFID be widely deployed in an economical, scalable, secure and manageable manner on WANs and LANs, even with the two-way demands of RFID data for networks and changes to RFID tags emanating from within the network.

Driven by speedy network processors and advanced software, RFID readers provide the same load balancing, QoS and security found in high-end IP routers. A tag reader will facilitate advanced applications by acting as a gateway between an IP network and tags that provide read-write data storage, on-board sensors and other features.

The network gateway functionality of RFID readers becomes even more critical in light of the channel-sharing, data-exchange and air-interface protocols required to accommodate two-way TCP/IP traffic. Before exchanging information with a tag, a networked reader searches for and retrieves the ID of each tag in its read zone. This discovery process produces a list of IDs, which then must be made available to an external software system such as a warehouse management system that resides on a remote networked server.

When the warehouse management system wishes to read, write and update data on the tag, it routes the updated data back to the tag via the reader through which the tag was orignally read. This is analogous to an IP routing procedure in which a reader forwards an encapsulated data packet to a specific tag.

The scenario is clearer in the case of sensor or actuator tags, which typically contain a miniature battery and are used for applications such as time-temperature monitoring of perishable goods in the supply chain.

First, the same networked discovery process applies in the case of sensor tags. Then, bidirectional communication occurs between the tag and software residing on a networked server. In some cases, such as time-critical movement of tagged packages on a conveyor belt, the reader might be given authority to act quickly on a networked server's behalf. This can be accomplished by running specialized software on the reader, or by implementing and populating a policy-based decision-making mechanism, mimicking those employed by high-end IP routers.

The new RFID readers are designed to provide the functionality of a gateway for large networks. RF interfaces to the tags reside on one side of a reader, with a database server and a TCP/IP network interface on the other side, fully equipped to be part of a networked-distributed data aggregation and analysis system.

How it works: RFID tag reader

Wasserman is vice president of development for ThingMagic, serves on the IETF Steering Group and is a member of the Board of Trustees of the Internet Society. She can be reached at margaret@thingmagic.com.

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