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Feature Article
August 2004

RFID: Should Networkers Care?


Department store product security tags, electronic toll collection, ID badges, and electronic automobile engine disablers are all being widely deployed. By the end of 2005, Wal-Mart expects to be electronically tracking pallets and cases for all products from its top 100 U.S. suppliers. The Healthcare Distribution Management Association (HDMA) in the U.S. is setting a goal for manufacturer and wholesaler deployment of tags bearing electronic product codes at the case level by the end of 2005 and for pharmaceuticals at the selling unit level by 2007. Healthcare is also looking to electronic tags to track patients to make sure they receive the correct treatment and drugs. Delta Airlines just completed a trial of radio frequency identification tags to track 40,000 pieces of luggage from check-in to loading on planes, achieving accuracy levels from 96.7 to 99.9 percent � 10 to 20 percent better than bar code scanners used today. The U.S. Department of Defense plans to require suppliers to use active and passive radio tags � at the lowest possible piece part/case/pallet level � on shipments to the military by January 2005, aiming to improve data quality, item management, asset visibility, and maintenance of material.

What do all these have in common? They are all using Radio Frequency IDentification (RFID) technology. RFID is an electronic way to collect identification, place, time, or transaction data on products and traceable items (including personal ID badges), quickly and easily without human error. Though originally invented in the 1950s, standards and technology evolution has brought the price down to enable mass deployment. RFID is a subset of a broader developing area called sensor networking.

Tag, You�re It
Every RFID system consists of a radio frequency (RF) tag, a transceiver/decoder and some form of antenna; and an event manager with interfaces into enterprise information systems. The antenna can be packaged with the transceiver/decoder to become a reader (or interrogator), which can be configured either as a handheld, or a fixed device. With few exceptions (e.g., retail security tags), the information gathered by an RFID system is networked in real-time, unlocking the power of the information systems and opening the door for more effective B2B systems.
RFID tags are attached to or embedded in the objects to be tracked, such as shipping pallets, product packages, bracelets, or ID badges. They come in a wide variety of shapes and sizes. Animal tracking tags, inserted beneath the skin, can be as small as a pencil lead in diameter and one-half inch in length. Tags can be screw-shaped to identify trees or wooden items, credit-card shaped for use in access applications, or embedded in paper labels. The anti-theft hard plastic tags attached to merchandise in stores are RFID tags. In addition, heavy-duty small pocketbook-size rectangular transponders used to track intermodal containers or heavy machinery, trucks, and railroad cars for maintenance and tracking applications are RFID tags.

RFID antennas transmit radio signals either continuously or are activated by readers, when they want to read and possibly write data to RFID tags. Antennas come in a variety of shapes and sizes; they can be integrated into handheld devices, built into a door frame to receive tag data from persons or things passing through the door, or mounted on an interstate toll booth to monitor traffic passing by on a freeway.

The reader controls the system�s data acquisition and communication functionality. The reader emits or receives radio waves in the range of one inch to 25 feet or more, depending upon power output of the transmitter and the radio frequency used. The reader most commonly interfaces to an event manager over a wireless or wired LAN, though the former will be preferred in factory and warehouse applications where wiring may be limited. The event manager is a RFID data collector, processor, and router that performs operations such as data capture, error handling, filtering, and monitoring, and is highly scalable and resilient to meet application needs. The primary benefits of an event manager are:

  • RFID reader functionality and protocols vary by vendor and model. Event managers are designed to manage this complexity without exposing it to back-end applications.
  • The volume of data coming in from readers can be enormous (even with some built-in filtering from readers themselves). An event manager is critical to filtering those data and routing only ones that matter based on business rules.
  • Warehouse applications and back-end supply chain systems present a heterogeneous enterprise environment. The event manager is a key component that provides abstraction from these different systems while offering a common format and protocol for communication.

An RFID tag is passive and is an alternative to a printed barcode. Passive RFID tags operate without a separate external power source. When an RFID tag passes through the electromagnetic waves generated by the reader, it becomes activated, allowing the reader to decode the data encoded in the tag�s integrated circuit. Passive tags are generally read-only and programmed with a unique set of data (usually 32 to 128 bits) that cannot be modified. Passive tags are light and small, inexpensive, and offer a virtually unlimited operational lifetime. On the other hand, they require a reader with adequate power to cover the range of the application.
RFID tags can also be active devices. Active RFID tags are powered by an internal battery and are typically read/write, that is tag data can be rewritten and/or modified. An active tag�s memory size varies according to application requirements, with some systems operating with up to 1MB of memory. An example of the application of an active RFID tag might be on an assembly line in a manufacturing plant. An RFID tag might give a machine a set of instructions, and the machine might then report its performance to the tag. This encoded data would then become part of the tagged part�s history. The battery-supplied power of an active tag generally gives it a longer read range. While active RFID tags provide greater functionality and run over longer ranges, the tradeoff is greater size, greater cost, and a limited operational life (depending upon operating temperatures and battery type).

RFID systems are also distinguished by the frequency ranges in which they operate. Low-frequency (135 KHz and 13 MHz bands) systems have short reading ranges and lower system costs. They are most commonly used in security access, asset tracking, and animal identification applications. High-frequency (UHF at 850 MHz to 950 MHz) systems are medium cost and will be the foundation for supply chain management environments. Yet higher frequency systems operating in the 2.4 GHz band are higher cost systems, offering long read ranges (up to 90 feet and more) and high reading speeds, and are used for such applications as railroad car tracking and automated toll collection. The significant advantage of all types of RFID systems is the automated, non-contact, non-line-of-sight nature of the technology. Tags can be read through a variety of substances such as snow, fog, ice, paint, crusted grime, and other visually and environmentally challenging conditions, where barcodes or other optically read technologies would be useless.

RFID tags can also be read in challenging circumstances at remarkable speeds, in most cases responding in less than 100 milliseconds. The read/write capability of an active RFID system is also a significant advantage in interactive applications such as work-in-process or maintenance tracking. Though it is a costlier technology (compared with barcode), RFID has already become indispensable for a wide range of automated data collection and identification applications that would not be possible otherwise.

At this time, there are a number of incompatible RFID systems for rail, truck, air traffic control, and toll-road authority usage. The lack of open systems interchangeability has impacted RFID industry growth as a whole, and kept RFID costs higher than would be achieved with broad-based inter-industry standards-based use. The good news is that a number of organizations have been working to bring about some commonality among RFID systems. For example, the ISO18000 standard has opened the door for RFID tag and reader manufacturers to begin producing products that conform to the standard. In addition, the market is moving towards a standard Electronic Product Code. EPC was developed by MIT�s Auto-ID Center (now called the Auto-ID Labs) and is now primed by EPCGlobal, a member-driven organization entrusted by industry to create global standards for efficient supply chains across multiple industries.

The Four Impacts of RFID
Firstly, many RFID applications require a networking solution that can reliably support connectivity between hundreds of readers and the event manager on the one hand, and between event managers and enterprise applications on the other. Clearly, loss of connectivity would be highly disruptive in a large distribution center and intolerable in a manufacturing facility. While the captured information per item is typically four to eight bytes, a superstore can generate a Terabit of information per day, and this data has to be delivered reliably and securely. Furthermore, as RFID moves to active sensors (e.g., for control of building security and environment), the amount of information captured will increase to Kilobytes/capture and the requirements for reliability and low latency can increase substantially. In addition, read/write active RFID tags likely will require a separate IP address, increasing the demand on the enterprise addressing space.

Secondly, RFID and WLANs are highly synergistic. Whether RFID readers are fixed devices or handheld devices (e.g., built into phones, PDAs, tablet PCs and laptops), they can take advantage of the attributes of WLANs. These can take the form of distributed WLAN Access Points (APs), leveraging power over Ethernet wired connectivity to the network, or wireless mesh networks, which can provide auto-configuration and dynamic routing for large areas such as warehouses without requiring Ethernet connectivity to each AP. These WLANs will not be dedicated to the RFID application, but will support a range of data and voice applications. They will be QoS enabled, secure, centrally manageable, and scalable, supporting tri-mode operation via 802.11a, 11b, and 11g. The optimal placement of WLAN Access Points is based on the desired coverage area for WLAN users, and that of RFID readers is based on the location of the objects being tracked. Therefore, while both are RF devices, integrating WLAN AP and RFID readers in a single unit may be of limited value.

Thirdly, as standards-based RFID systems start being deployed across industries, there will be an increasing opportunity for networking vendors to add RFID content intelligence to routing and switching products. This could be used to better secure and manage the flow of information across the network or to provide load balancing across servers, while increasing the reliability and security of the overall RFID system.

Lastly, when RFID-based employee ID badges or patient bracelets are networked, the information captured can be retrieved by presence management systems to enhance collaborative rich media communications and provide location-based and presence services. For example, in healthcare environments, calls to a surgeon in an operating room should be routed elsewhere; security staff should be alerted if a newborn is removed from the pediatrics ward; or a doctor wishing to examine a radiologist�s report may be able to use a display device next to which he is standing.

Taking Tags to the Bank
RFID systems are proliferating across a broad range of environments. Improved supply chain management, inventory controls, location services, and sensor networks will have significant impact on both business applications and B2B processes. As networkers, we have to understand this technology, and the opportunities and impacts it represents on our networks and on our businesses, so that we can deliver the optimal benefits of RFID to our enterprise.

Tony Rybczynski is the director of strategic enterprise technologies for Nortel Networks. He has over 30 years experience in the application of packet network technology. For more information, please visit the company online at www.nortelnetworks.com.

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