a) Infrastructure Access, Maintenance, and Costs With containers, there is a fundamental requirement: antennas at fixed locations. There is a need for physical infrastructure and equipment on the ground, either fixed, or handheld. Handheld transceivers bring in the human element with the resulting higher costs, damage, maintenance, or loss. Regardless, they are needed so when changes in the container status are, they can be transmitted by RF signals when, and only when, the container is interrogated by a transceiver physically positioned or used in the case of handhelds. somewhere along the global supply chain. The fixed transceiver, through an antenna, sends the triggering frequency, which carries a request for a return transmission of any change of status of the container since the last time it passed an antenna and transceiver. The message could be that the container was breached somewhere in-route.

Since the transmission of these data is by radio frequency, the successful transmission is subject to not only the use of government-approved frequencies or waves, but also the absence of distortion like noise or same-frequency emissions from competing antennas whose direction (footprint) unintentionally or intentionally obstructs or interferes with the intended RFID transmissions of the intended transponder. Thus, so far there are some very clear weaknesses: first, the need to own or lease property to place an antenna; second the absence of interfering RF signals which cannot be guaranteed; and third the historical nature of what information is transmitted, a very critical weakness. For instance, the last place one wants to learn that the container was surreptitiously accessed and an explosive device placed in it destined for the United States is at the foreign port of departure or at the U.S. port of arrival since these ports are where most of the transmissions take place. Finally, all these multiple antennas and transponders at fixed sites must first be permitted to be installed and then must be maintained and functional.

b) Frequencies and Protocols There are no global standards for frequencies or protocols. Protocols are basically the instructions on how the messages are transmitted over a certain frequency or carrier of the message. Imagine the lack of standardized instructions for a container and its transponder on a global voyage, i.e. China to South Africa to Europe and then to the U.S. Different regions will have different standards. There are national standards like ANSI ( ), international standards like ISO (International Organization for Standardization), and industrial standards like EPC (EPCglobal, Inc. which alone is in about 100 countries).

For instance, RFID frequencies on which the data ride in the United States will not work in another part of the world. The foreign transceiver cannot trigger the data transmission because the U.S. may use a different frequency or protocol. Therefore, RFID for container security is applicable only to those areas of the world which have agreed on the same frequency. This weakness is in addition to the corresponding need for a land-based infrastructure of antennas and readers. Unlike RFID tags used in products and pallets that are read in controlled distribution systems, active RFID devices in containers that move around the world through uncontrolled environments, require the construction of antennas at global chokepoints where containers are interrogated. Who determines the number and location of these points?

Constructing a controlled distribution path globally is really impossible. Typically, chokepoints are locations where readers could be positioned that cannot be avoided by the carrier of the container. They include the spot where a truck is loaded or unloaded, on a crane that transfers containers, a weigh station, the port of loading, or at the port of discharge. Only for these obvious chokepoints at origin and destination, is a land-based system a reasonable option. In areas along the route of the container's movement, a land-based system is virtually impossible to establish.