SUPPLY CHAIN OVERVIEW
1.4 RFID TECHNOLOGY INFRASTRUCTURE
Lesson learned: Eliminate the costly mistake of delivering the pallets to the wrong distributors and customers.
to log data into a database or remote servers, monitors for event changes, and sends alerts to its intended recipients.
The Savants then forward data to the ERP systems, including SCM and Supply Relationship Management (SRM), virtualized databases, and SAP via middleware technologies through a full-time connection to the readers, or synchronizing data on an “as needed” basis. The Savant’s real-time in memory database (RIED) structure is used to store event information, sup- port SQL queries, and take “snapshots” of the database at different times.
Savant software works with Windows 9X, NE, NT, 2000, and XP and can be downloaded at no cost fr om Savant Web Server’s Web site at http://savant.sourceforge.net/. The original version of this software running on distributed servers was designed by the Auto-ID Center for its EPC Figure 1.4 RFID Technology Infrastructure
Retailer’s EPC IS
Retailer’s EPC IS
Retailer’s EPC IS
Windows 9X, ME.NT
2000.XP Savant server
collects data, monitors events and manages tasks
Tag Tag Tag Tag
Tag Tag
Tag Tag Tag Tag
Tag Tag
Tag Tag
Tag Tag
Tag Tag Reader
Reader Reader
Reader Reader Reader
EPC Global Network ONS
Service
EPC Middleware Application server
Manufacturer’s EPC IS
Supply Chain Management Supplier Relationship
Management
electronic applications–
internal and Internet New or wrap up
systems Legacy systems Virtualized databases API
Integration hub Middleware technologies Customer Relationship
Management Savant
server
Savant server
Savant server
network infrastructure. For the software to work properly, the Internet Information Services (IIS), at least, must be turned off.
The Savant server can be customized to receive all the different data communications among readers, RS232, RS485, TCP/IP, and Ethernet. You can connect mini-servers to communicate with the main Savant server or mini- Savants. These mini-servers can convert all data signals to an Ethernet that has the ability to multiplex 900 readers or more—passive and active—at a time.
The time elapsing between the client request and the server response is extremely fast and can serve over 100 simultaneous connections. These two features allow a reader to scan multiple tags at one time in a second or two.
Sun’s version of Savant is available for managing the flow of RFID information between the readers of RFID tags and the back-end enterprise system. It contains reader failover features to allow the RFID information to continue to flow to its intended destination. Resource [7] gives details on Sun’s EPC Networking Architecture.
ConnecTerra is another company that offers a middleware RFTagAware 1.0, the first version of its EPC Savant and reader management software.
This software provides an Application Programming Interface (API) for data filtering and integration in various formats with enterprise software.
RFTagAware also monitors the health of remote readers, upgrades soft- ware, runs diagnostics, and performs other maintenance operations.
1.4.2 Major Vendor Servers
When a Savant server reaches its disk capacity limit, the organization needs to consider RFID servers from major vendors, such as IBM, Oracle, and MS SQL Server.
Some issues to be considered are whether the organization should treat RFID technology as one of the sensor-based services or it should focus on a RFID database middleware that collects and interprets RFID events and escalates them to critical operational events or both. Oracle and IBM are examples of each, respectively.
Oracle Sensor-Based Services [8], an RFID-ready Oracle Warehouse Management was demonstrated at the RFID Journal Live! Conference in late March 2004. Based on Oracle Database 10g, Oracle Application Server 10g, Oracle Enterprise Manager 10g, and Oracle E-Business Suite 11i, Oracle Sensor-Based Services enable companies to integrate sensor-based informa- tion into their enterprise systems to achieve supply chain visibility in real-time.
Making up the Sensor-Based Services are primarily two middleware components: the Compliance Package and RFID Pilot Kit. The Compliance component allows companies to address the specific and unique reporting requirements coming down from major retailers and the U.S. Department of Defense. The Pilot Kit is more suited for smaller companies that only
need drivers for the major RFID readers, and some reporting and analytic tools to process RFID data.
Oracle Sensor-Based Services provide capabilities to capture, manage, analyze, access, and respond to data from sensors such as RFID, location, and temperature. It allows users to query and audit specific events occurring in the system, and to receive alerts on recalls of a bad batch of products.
IBM, known for providing the overall systems integration for RFID at the METRO Group, is integrating RFID with DB2 Information Integrator for Con- tent. It provides structured enterprise information via connectors to DB2 rela- tional databases. The IBM product is made of three different elements: Devices, WebSphere RFID Premises Server, and a WebSphere integration server.
Readers, scanners, and printers are embedded with the first element, Web- Sphere RFID Device Infrastructure. They also include other sensor devices that come with RFID, such as temperature. The second element, IBM WebSphere RFID Premises Services is a middleware product that interprets RFID events to detect operational events, such as the sudden change in temperature of perishable products while being transported in a vehicle. The third element is an IBM integration server, such as WebSphere Business Integration Server or Server Foundation, unlike Oracle that offers an application server and E-Business Suite applications for a variety of data types across the enterprise.
As of January 2005, IBM has planned for a SAP-specific database, that is, DB2 specifically tailored to run SAP applications (e.g., DB2 for SAP). So what is the relationship between Oracle and IBM as a result of the People- Soft acquisition? Because PeopleSoft includes J.D. Edwards, with a strong legacy of applications running on IBM’s iSeries (or AS/400) platforms, even though the bulk of PeopleSoft applications run on Oracle databases, Oracle has made commitments to support customers running Oracle/Peoplesoft wares on IBM middleware and databases. Improving Oracle’s rapport with IBM is a number one priority.
1.4.3 Tags
RFID tags for a case hold a wider range of data about the product and the manufacturer than the tags for individual items. This saves time and cost of opening the case, taking out each product to read its label, putting back the products, and repacking the case, as the cases or pallets move from one end to another in the supply chain. The amount of data a tag can read depends on the memory size in the tag, the frequency range for it, and the tag class it is assigned.. Tags work as long as they do not fall off cases or pallets, are not affected by the offending materials, and are highly visible during the transport.
When active tags with battery power come into the field of a reader, the reader switches to the read mode and interrogates the tag. Although these
tags are suitable for longer distance, they are more expensive than passive tags due to more complex circuitry of the tags and the battery’s weight.
However, RFID tags do not work with all material types. They work well as long as the packaging material and its contents do not contain offending materials, such as metal, liquid, and dense materials (frozen meat and chicken parts) that can adversely affect the tag readability. Readers will also have a hard time detecting tags that are near the nylon conveyor belts. The frozen meat and chicken parts will need to be packaged in plastic bags to which the tags can be affixed. The tags will need to be repositioned on bottles containing liquid, so that a tag would be optimally located (e.g., further away) on the dishwashing bottle from the liquid.
To distinguish tag types from each other, EPCglobal has established five tag classes to indicate capabilities a tag can perform as indicated in Table 1.2.
For instance, Class 0 tags are factory programmable. The EPC number is encoded onto those tags during manufacture and can be read by a reader.
Class 1 tags can be programmed by the retailer and supplier. They are manufactured without the EPC number which can be encoded onto the tag later in the field (i.e., by retailer and supplier).
The Class 3 tags have the Class 2 capabilities plus a power source to provide increased range or advanced functionality. The Class 4 tags have the Class 3 capabilities plus active communication and the ability to communicate with other active tags. The Class 5 tags have the Class 4 capabilities plus the ability to communicate with passive tags as well.
Not mentioned in the table are the Class 1, Gen. 2 tags which take into account the interoperability issues between Class 0 and Class 1 tags. It is not possible for the retailer or supplier to duplicate the EPC number in Class 0
Table 1.2 Tag Classes
EPC tag class Tag class capabilities
Class 0 Read only (i.e., the EPC number is encoded onto the tag during manufacture and can be read by a reader)
Class 1 Read, write once (i.e., tags are manufactured without the EPC number which can be encoded onto the tag later in the field) Class 2 Read, write many times
Class 3 Class 2 capabilities plus a power source to provide increased range or advanced functionality
Class 4 Class 3 capabilities plus active communication and the ability to communicate with other active tags
Class 5 Class 4 capabilities plus the ability to communicate with passive tags as well
Source: Hardware Program Configuration, EPCglobal, 2004 at www.epcglobalinc.com.
tags in Class 1 tags; that is, the EPC number in Class 0 tags is not transferable to Class 1 tags. Generation 2 consolidates multiple protocols specified in Generation 1 as a single protocol.
Obviously the Class 0 through Class 2 tags are passive communication types and Class 3 tags are semi-passive types which are the passive tags with a power source. The Class 4 and Class 5 are active communication types.
To sum it up, the complexity of an EPC tag depends on the functionality of the tag, how it communicates with the readers and other devices, and whether it has a power source. Increasing the complexity of tags also increases the cost. Tags with advanced functions require more expensive microchips, and tags with a power source require a battery.
1.4.4 Antennas
Of importance to antennas are orientation, position, proximity, and reading zone. All are related to one another. None can be isolated without consid- ering the other two. Chip antenna is not the same as the reader or conveyor antenna. If the vendor talks about an antenna, you may need to double- check to which antenna type the vendor is referring.
For instance, read-only RFID tags from Matrics (now known as Symbol Technologies) that come preprogrammed with customer-supplied EPC codes are available with one or two antennas. These tags have the read rate of up to 1000 tags per second and long read range of up to 30 feet.
Read-only tags with one antenna are available in five types (see Chapter 2,
“RFID Technology”). Each tag type indicates what materials it can be applied to, in what forms are available, and what the maximum reading distance is.
The read-only tags with one antenna of general-use type work best with general-purpose use on plastic, corrugated cardboard, bagtag, and plastic.
They are in the form of inlay, adhesive inlay, and label. Next in line are rubber encapsulated and UV-protected glass tags that have reading ranges of 15 feet for metal, and glass and windshield, respectively. The glass bottle and concrete tags have the lowest reading ranges.
The read-only tags with dual antennas can be read from any orientation and are available in three types (see Chapter 2). Each type indicates what materials it can be applied to, what forms are available, and what the maximum reading distance is. The smaller the tag, the more likely it is limited to one antenna.
The tags (generally passive) with one antenna must be in proper orien- tation, as some cannot be easily reoriented to receive adequate reception of radio wave signals. The antenna in tags usually cannot be oriented as you can do with the TV antenna to get better reception for a channel. When you place the products in a shopping cart in a random orientation given the restriction that the antenna cannot be reoriented, the reader may or may not be able to read all the tags in the cart. The antenna orientation in some
tags may interfere with the orientation in other tags. When a shopper uses a reader to get the information on all items in the cart, the information on some tags may not show up or may get distorted on a check-out computer screen. This means the tagged items in the shopping cart must be taken out on the check-out counter for proper alignment of the items’ orientation.
Even if the tagged items are placed in a proper orientation order in the cart to prevent signal interference, mobile RFID handheld readers (e.g., the shoppers) in close proximity to another may garble data while scanning the tags. The radio frequency field generated by one reader used to scan the items in one cart may overlap the field of another reader used to scan different items in a second cart that happens to be in close proximity to the first cart.
For active tags, the reader cannot communicate with a tag that is oriented perpendicular to the reader antenna. A minimum of one antenna must be located in one zone. Although several antennas enable more accurate tag positioning, improper positioning due to reflections from walls and equip- ment can adversely affect the transmission from the batteries. The tags that are not located in the correct horizontal or vertical levels in buildings also affect the transmission quality.
Let’s look at how Canus resolved the antenna problem. The Canus docking door allowed only three antennas to be set up. It found the third antenna did not allow enough reading area. Adjustments were made to this antenna by changing its orientation and position to provide a greater read- ing area for the antenna. A fourth antenna was added to ensure that a tag can be read regardless of its location on the pallet.
In sum, the antenna, orientation, position, proximity, and reading area as well as tag placement are important to ensure optimal reads provided, for instance, the tags are not attached or near the offending materials, and the speed of tags does not affect the quality of input reads into a laptop.
1.4.5 Readers
Readers come in four types: handheld, vehicle-mount, post-mount, and hybrid. The first three are dedicated to reading of the tags, active or passive.
The fourth type has the active/passive mode allowing it to switch from the passive to active mode and vice versa. Both handheld and hybrid readers are more expensive than the vehicle-mount and post-mount. Next genera- tion readers are expected to have less power consumption and fewer voltage requirements.
Passive RFID readers create a radio frequency field when they are turned on. When a reader detects passive tags, it activates them. These tags draw their power from the radio frequency field; they do not require battery power. Because they have no battery, the passive tags are smaller and lighter in weight than active tags. Some are as light or even lighter than the bar-coded labels.
When the active tags with power come into the reader’s field, the reader switches to the read mode and interrogates the tag. Although these tags are suitable for longer distance, they are more expensive than passive tags due to more complex circuitry of the tags, and the battery’s weight. Tag prices, however, will be less as the demand increases.
The proximity of the RFID-tagged items, cases, and pallets to the vehicle- mounted or post-mounted readers is predetermined for input reads optimi- zation. The proximity of the RFID-tagged items, cases, or pallets to a mobile RFID reader can vary if the reader is within the acceptable reading zone. If the proximity of this reader is too close to the RFID-tagged items, say, in a shopping cart, collisions may occur, as standards to share common radio frequency fields and bandwidths are either unavailable or not officially approved for industrial application. For this reason, RFID is more suited in manufacturing, retailing, and logistics supply chain where the readers are placed at strategic points in the supply chain such that one reader will not interfere with another reader while reading the items.
1.4.6 Electronic Product Code
So, what does an EPC look like? An EPC is a unique 96-bit or 64-bit number embedded onto an individual RFID tag. It divides the information into four partitions in respective order:
Header EPC Manager Object Class Serial Number
The first two are assigned by EPCglobal and the last two by EPC Manager [9]. Each partition is assigned a range of bits and separated with a dot something like this:
01.0000A13.0005E.000158DC0
As shown in the first highlighted portion of the code in Figure 1.5, the Header partition identifies the EPC’s version number and defines the num- ber, type, and length of all subsequent data partitions. Particularly for the 64-bit version, the Header partition specifies how the EPC coding scheme should be expanded, changed, or modified [10].
The second highlighted portion of the code in Figure 1.6 is the EPC Man- ager partition. It is concerned with the name of the enterprise, such as the name of the manufacturer. Your company reference number in your bar code should be consistent with what you would use in your EPC Manager Number.
In Figure 1.7, the third highlighted portion is the Object Class partition.
It refers to the class of product, such as the manufacturer’s laser paper item of certain brightness, weight, color, and number of sheets.
Figure 1.5 Header Partition
Figure 1.6 EPC Manager Partition
Figure 1.7 Object Class Partition
Figure 1.8 Serial Number Partition
01.0000A13. 0005E.000158DC0 EPC version number 01
01.0000A13. 0005E.000158DC0 Manufacturer’s name (Office Paper Supply, Inc.)
01.0000A13. 0005E.000158DC0 Class of product, usually the stock keeping number (SKU)
Laser paper
01.0000A13. 0005E.000158DC0 Serial number unique
to the item
In Figure 1.8, the fourth partition is the serial number unique to the item.
The 96-bit EPC provides unique identifiers for 268 million companies.
Each company can have 16 million object classes, with 68 billion serial numbers in each class. Because we do not need so many serial numbers, a 64-bit code, proposed by the Auto-ID Center (now EPC Global), has been used to help keep down the price of RFID chips. It costs somewhat more to encode additional bits on the RFID tags. Although the 64-bit code seems to be a good way to lower the costs, it may not “meet all the requirements of manager, object and serial numbers” [10]. To get around this problem you would need multiple versions of the compact version, as shown in Table 1.3.
Versions 1 and 3 are more appropriate for a single organization and Version 2 is better suited for a large global organization. The single organi- zation may have many object types and serial numbers. Not shown in the table is a possible version for a single organization with few object types and many serial numbers.
When RFID technology matures and the increased demand lowers the costs of implementing the technology, we will see the 96-bit code for more items, cases, and pallets, as it may be advantageous to encode additional information about the product. In the years to come, we may see a 128-bit code for all items around the world only if a new technology will help to keep down the costs of encoding many bits on electronic tags. How this code will interface with IPv6 which also has an identifier length of 128 bits in the world of grid computing is a good question.
1.4.7 Object Name Service
ONS is an automated networking service similar to the Domain Name Service (DNS). What DNS does is that it directs a computer’s Web browser to the correct Web server for the Web site an Internet user attempts to access. DNS is an Internet service that translates domain names that we can easily remember (www.yourdomain.com) into IP addr esses (e.g., 134.137.234.35). Every time we use a domain name, a DNS service must translate the name into the corresponding IP address. The DNS system is
Table 1.3 Three 64-Code Versions
Partition Version 1 Version 2 Version 3
Manager numbers Few Many Few
Object types Many Few Few
Serial numbers Many Few Many