August 2004
RFID: Should Networkers Care?
BY TONY RYBCZYNSKI
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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