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RAM Mobile Data Another large packet switching wireless WAN provider is RAM Mobile Data, which has a multiuser packet radio data communications network that covers the largest 266 US metropolitan areas, and also airports and major transportation corridors. This includes more than 92% of the urban business population. British Airways uses RAMs wireless service to decrease the time for passenger check-in for its international flights by obtaining better control over baggage and cargo handling and decreasing aircraft servicing time. With RAMs service, British Airways can now liberate passengers from long lines at the check-in counter and customs desks by bringing portable terminals directly to the passengers waiting in line. The portable computers contain the same passenger, flight, and fare information as the airline's traditional counter-top computers. AT&T Wireless Services McCaw (now AT&T Wireless Services) has a service called AirData that uses cellular digital packet data (CDPD). CDPD, which was developed by McCaw and cellular carriers, is a standard specifying the transmission of data at 19.2K bps over analog cellular telephone networks. CDPD sends data over unused voice channels. The advantage of CDPD is that it is becoming an open standard. Intermountain Health Care, Inc. (Salt Lake City UT), has embraced AirData for a variety of health-care applications. AirData addresses important health-care needs by providing speedy access to mission-critical information (e.g., patient records, lab reports, and reference materials). IMPLEMENTATION ISSUES If a wireless solution is feasible, it is important to consider the following issues before purchasing the components and beginning the installation: potential security problems, potential radio interference, and lack of interoperability (i.e., lack of mature standards). The main difference between wireless and wireline networks is that wireless networks propagate their signal over larger areas, making the signal easier to receive by an intruder. However, with proper data encryption, an intruder is unable to decipher and understand the data. Electronic sabotage with wireless networks is a much greater risk than with conventional wireline networks. A saboteur, from outside the facility of a wireless network, can easily block the transmission of data by continually transmitting a signal on the same frequency band. This can be a serious problem if an organization stands a great deal of risk if their computer network ever becomes inoperable. With wireline networks, this process would be more difficult and risky for the saboteur because a device would have to be directly attached to a cable within the facility. As mentioned earlier, wireless products using the ISM bands do not need special FCC licensing. Therefore, the FCC does not manage the use of products operating within the ISM bands. This often sets the ground for interference between products operating within close proximity. This interference temporarily blocks network components from being able to send data across the network, resulting in delays lasting as long as the interference is present. The key to a successful installation is to survey the location where the wireless components will reside and ensure that there will not be significant interference. Organizations are busy developing standards for wireless LANs and WANs, but official standards have been slow to emerge. As a result, current wireless networks products from different manufacturers are not directly compatible. Until standards are finalized, the only method to provide interoperability between dissimilar wireless LAN products is through the use of network bridges, which can tie the dissimilar LANs to a common protocol (e.g., Ethernet). SUMMARY The need for wireless networks is becoming more solid as organizations require mobility and alternatives to expensive cable installations and reconfigurations. Is a wireless network a feasible alternative for every organization? Wireless solutions for LAN and WANs are definitely available, and future developments in technologies and standards will only increase data rates and decrease product costs. For example, research groups are actively finding ways to improve portable computer battery use that will leave more power for wireless communications signals, therefore supporting higher data rates. In addition, research dealing with compression techniques should lead to better use of existing bandwidth. The finalization of standards (e.g., IEEE 802.11), will lower product development costs, allowing hundreds of smaller companies to develop and sell wireless adapters at relatively low costs.
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