Going mobile has its price. Extending the reach of corporate networks to support a more mobile work force is fraught with problems such as immature technology, indifferent support and a lack of a nationwide wireless infrastructure, according to early corporate adopters. Nevertheless, the time is ripe to examine this technology and determine pilot project requirements. Current wide-scale wireless implementors such as United Parcel Service package delivery drivers and IBM's own field service technicians use specialized devices that have built-in wireless communications, rather than using commonly available PCs. Part of the problem lies with the traditional networking vendors such as Novell, IBM, and others who have not -- until recently -- considered the kinds of free-flowing connectivity that is offered by wireless attachment. And part of the problem is that users are still in the dark as to the most effective deployment of wireless applications, even those who are enamored with the technology. "Most people haven't figured out what wireless networks are good for, why they need it, and what it does," says Dick Shaffer, editor of ComputerLetter in New York City and a long-time follower of the technology. (See Sidebar 1 on obstacles.) One that has figured it out is the Swiss Bank Corporation, with offices around the world. "We needed mobility, because we wanted to hire technical support people in the US and compensate them to be on call 24 hours a day," says Dwight Koop, Executive Director of Information Technology for the bank. Koop has bought thirty mobile palmtops for his support staff and executives, and plans on deploying more. There are principally two different types of wireless connections that corporate networkers can take advantage of: in-building and around town. In-building products include those from Motorola's Altair division, Xircom's Cordless adapters, Proxim, and AT&T's NCR WaveLAN group. These are essentially wireless network bridges, devices that have both an ordinary network adapter to connect to the wired network and radios that support small groups of mobile users within a very small roaming area. They typically have speeds less than 2 megabits/second and a range of a few hundred meters. The second type, and the focus of this feature, concerns extending mobility to a nationwide level. Here, users subscribe to a utility similar to a cellular phone provider that connects their computers via a network of radio towers placed around metropolitan areas and alongside highways. Special radio modems are connected to the computer's serial port and transmit and receive data to the nearest radio tower owned by the provider, which in turn sends signals to the ultimate destination. This could be applications running on the user's own mainframe computers or another computer system owned by a service bureau. The point of this nationwide network is to enable users (such as travelling executives or salespeople) to roam freely about the countryside, keeping in constant touch with their cleitns and home office colleagues via electronic mail without the need to find a telephone connection.This becomes a tremendous boon to travelling salepeople, for example: Eric Rupert is a Delware-based consultant who "travels to many clients where I might not have a [wired] modem or even a desk. The ability to send and receive messages anytime and stay in touch with the manufacturer's sales reps is very convenient." Swiss Bank's Koop agrees that wireless email is convienent: "When I travel, I don't have to rip apart the hotel's phone system to get connected anymore." Wireless computing makes it possible to compute anywhere, at anytime, even at times that are ordinarily impossible: "While sitting at a conference, I arranged a visit for the next day, dinner that evening, and who would be picking me up the next morning, and made arrangements for a fax to be sent to my hotel," says Dr. Mark Weiser, Director of the Computer Science Laboratory at Xerox's Palo Alto Research Center. Three systems: RAM, Ardis, and CDPD For two-way data communications, there are three main wireless carriers that are currently operating across the country: RAM Mobile Data, Ardis, and a new group formed around the Cellular Digital Packet Data (CDPD) specification that is just getting started this summer. Each of the three systems has different technical specifications and geographic coverage. And each uses different sets of transmission equipment, switchgear, end-user radio modems and protocols. None are compatible with the others. For example, both Ardis and CDPD operate at 800 Mhz frequencies, but space their signals differently. RAM operates on a completely different frequency (900 MHz) and spacing. This means that radio modems have to be built to work with one system only. Ardis is the oldest of the three systems and has the broadest coverage in over 400 metropolitan areas. They claim this covers over 90 percent of the business locations in the US. They also have the greatest number of subscribers (estimates vary, but Ardis claims more than 35,000). Ardis was started in 1984 to provide wireless service to IBM and Motorola field service representatives, and became a private enterprise in 1990. Ardis also claims its coverage inside buildings is the best of the three providers. Indoor coverage is critical if users want to be able to send and receive information while at their desks, as opposed to having to bring their computer outdoors or close to a window. (see sidebar 2 on Throughput) RAM began operations in 1991 and built its coverage rapidly, with service presently in over 100 metropolitan areas. RAM is designed for nationwide roaming, so that a user doesn't have to do anything when he or she gets off an airplane to send information through the RAM network. Ardis has not yet implemented nationwide roaming. [CHECK] Because of its relative youth, RAM has fewer subscribers than Ardis (analysts have pegged RAM at less than 10,000 users). Most users of RAM were satisfied with the coverage received: "I travel all over the U.S. and the only time I didn't get coverage was at a ski resort in Utah," says Mark Weiser. "The service is quite weak in some areas, although it still works. I have a found a few places that I could not get coverage, usually rural areas," says Eric Rupert,. "It doesn't work at my house, so what I am supposed to do: move?" asked Dwight Koop of the Swiss Bank, who lives in the Chicago area."For general business applications, the coverage meets our needs," says Michael Mushet, General Manager, power systems for Southern California Edison, Rosemead, Calif. "As an electric utility, our service areas extends to many locations that do not have any type of coverage other than our own radio system. We are currently satisfied with RAM and see no reason to switch." The two networks have different typical users. The vast majority of Ardis users are field personnel or delivery drivers, versus RAM's bent towards supporting more mobile office workers and executives. To mirror this focus, RAM and its partners sell a one-stop kit to get a single user up and running on its network that includes the wireless modem from Ericsson GE (called a Mobidem) and software from RadioMail Corporation. (The kit costs $995 including an HP palmtop, or $775 without it for just the Mobidem and software. There is a one time $99 fee to start service and a monthly charge of $89 for unlimited messages sent through the system.) PSI, Inc. also sells software at roughly similar prices that works with the HP palmtop and the Mobidem, and has the additional advantage of being able to communicate with ordinary land-line modems when RAM coverage is not available. RadioMail: enabling messaging anywhere RadioMail works as follows. Subscribers require a wireless modem, a computer, software and an account. RadioMail creates a mailbox at their computer center in San Mateo, Calif. This mailbox is separate from any other electronic mail identities that a user may have, and is identified as "user@radiomail.net" on the Internet. Users connect to this mailbox via the RadioMail software, which is available as an application running on DOS, Macintosh, or several palmtops. Mail that is destined for other Internet users goes through the RadioMail computer center and out via ordinary telephone circuits to other computers on the Internet. However, unlike most Internet connections, RadioMail is limited to just messaging and does not provide full Internet access to file transfer (called ftp) and remote connection service (called telnet). "I have been pushing RadioMail for several months now to provide telnet and ftp to provide more remote support from the road," says one user of the service who wishes to remain anonymous. "The ability to do ftp and add files as an attachment to an email message would make the service more useful," says Eric Rupert. Currently, the sole wireless modem that can be used to access the RAM network is the Mobidem, from Ericsson GE Mobile Communications. It weighs about a pound, has rechargable batteries that last about six hours of continuous use, and connects to the serial port of a computer with a special cable. Ericsson and Intel are working on a second version of the Mobidem which will be compatible with the Hayes AT modem command set. According to company representatives, it will be available this fall. This AT Mobidem is not compatible with the existing Mobidems, however. Third parties such as AT&T's Easylink and Lotus' ccMail have promised to ship products that make use of the AT Mobidem this fall. And to top off the list of promised devices, Motorola has announced a PC credit-card adapters to be available next year that will communicate on the RAM network, and a separate adapter for Ardis as well. There are several devices that connect to the Ardis network. One is Motorola's InfoTac, similar to the Mobidem in that it provides two-way connections and connects to a PC's serial port. However, unlike the Mobidem the InfoTac can also function independently of a PC and has the ability to store and respond to messages. Motorola also manufactures a number of other wireless modems that are OEM products and have been incorporated into a number of field-service-specific data terminals, such as "the brick" carried by IBM sevice technicians. This device is about the size of a block of masonry with a small LCD display and keyboard. And Ardis also supports RadioMail [check - is this now available on the InfoTac?]. CDPD: on the horizon CDPD is still new, with the specifications just finished within the past month. McCaw, GTE, and other cellular carriers and equipment providers are still in the test and development phases. The specifications describe how existing cellular voice carriers can augment their systems by carrying digitial data "conversations" during the lulls of voice calls. Many companies have promised end-user equipment, but the system has no paying customers and no current production applications. Here is how CDPD will work. Cellular carriers will have to upgrade each cell site in their network to be able to handle data communications. These upgrades will not be cheap: analysts estimate many millions of dollars will be required to add the necessary switches and radio gear. And given that there are nine thousand cell sites around the country, these upgrades will take time. McCaw representatives have stated that they will have at least 50 of their major market areas upgraded by the end of 1993 (about half of their national network), although many industry observers think this schedule is overly optimistic and think it will take at least till the end of 1994 to reach this penetration. "It took the telephone 70 years to go from product introduction to where half the US population had them. Cable TV took 40 years. This stuff isn't going to happen overnight," says Technologic's Shaffer. McCaw and GTE have been conducting field trials on their systems in San Francisco/San Jose coridor and McCaw has said its first CDPD implementation will occur in Las Vegas later this summer. In addition to new cell site equipment, manufacturers will have to produce new customer radio modems to work with CDPD radios. These could take the form of a combined cellular modem that communicates on both the existing analog network as well as over the CDPD network, or it could be separate devices: there haven't been any actual products as yet. Which of the three systems will win? No one wants to make that call, although Shaffer thinks CDPD will drive developments on Ardis and RAM: "CDPD is an important potential solution, since people understand what cellular phones do and the level of potential coverage is greater than RAM or Ardis," says Dick Shaffer. "However, if your application has to work today, and workers must communicate, the only answers are RAM and Ardis." (end of main story) ________________________________________________________________________ Sidebar 1: Issues and Obstacles to Wireless Networking There are eight critical issues that need to be resolved before nationwide mobility will become as easy as connecting two computers via Ethernet cable. 1. Synchronicity. Perhaps the biggest issue for the current crop of RadioMail users is being able to keep up with their various electronic mail addresses and synchronize their information. Most of them have a RadioMail account in addition to whatever electronic mail systems they use at their offices. RadioMail is connected to the overall Internet mail network, and as long as the office network email system has some means of getting messages to the Internet, the two systems can communicate with each other via gateways. These users offered several ways that they are working around this problem. One method is to use the RadioMail computer for just email, and do all other applications on other platforms. "I keep no information on the various platforms that I use for RadioMail," says Xerox' Dr. Weiser, who uses the HP palmtop and a Macintosh for his RadioMail and has a second email account on his office network. " I just real the mail there and either throw it away or forward it to my main account at the office. I use RadioMail for those urgent little things, and only when people specifically send them to me there." Delaware-based consultant Eric Rupert agrees: "I only do email on the palmtop." But what about the situation where you need to transfer files back to the office computer? Users offered two solutions: email or file transfer. "I use [the built-in Travelling Software's] Laplink to move files back and forth from the HP palmtop," says Rupert. Still, having two email accounts is one more than most people want to deal with. "An issue is the multitude of email address each of us is developing: someone needs to solve that problem," says Southern California Edison's Michael Mushet, who uses both RadioMail and PROFS at his office. "We have discussed internally developing a redirector and while easy, we have not yet done it. We still need to retrieve our PROFS messages separately." Edison's PROFS email system is connected to the internet via two gateways: Softswitch and ATTMail. 2. Coverage. National coverage is still not a sure thing. While coverage for RAM and Ardis is good in many metropolitan areas, that isn't the same as being able to connect from any location. "In many respects, the issues surrounding coverage are identical to when I first got my cellular car phone," says the Swiss Bank's Koop. "Coverage will continue to improve as vendors continue to deploy their networks." What is needed though are more solutions like PSI, that offer alternatives to radio connections: "When we get to a place where we can't get coverage from RAM, I would like to be able to have a convienent way to get email over regular land telephone lines," says Koop. CDPD is still a wild card in terms of coverage, since the system is just getting started. However, there are already some weak links, as US West has dropped out of the consortium. This means that coverage might not be as good in its service area of the Rocky Mountain and plains states, according to some analysts. 3. Marketing. Most of the wireless products have not been marketed as computing devices, reflecting their telephony heritage. Some of this is because they have sold as replacements for beepers, rather than as extensions to the LAN. For example, "the Mobidem has an RJ45 connector, showing that telephone engineers originally designed it," says Bill Frezza, director of marketing for Ericsson. The pager nevertheless is a good model to follow: "RAM and others have done an inadequate job of marketing, and the gadgets have to as easy to use as a pager," says Technologic's Shaffer. Koop agrees: "We want to evolve from beepers to more sophisticated applications." 4. User interface. "RadioMail for many users is still a first-generation product," says Frezza. This means that many user interface issues still need improvement. "RadioMail should work like Unix mail: a reply sends the entire previous message, a built-in intelligent address book, make good use of an 80-character screen, and so forth," says Swiss Bank's Koop. 5. Better standards. CDPD is still evolving, with the complete specifications only finished last month. RAM uses the Mobitex standard, which covers how data is put into packets and transmitted over a radio frequency. This standard, which has evolved over many years, has been adopted by several European countries. However, there is one catch: they use different radio frequencies to transmit the data, meaning that the US Mobidem won't work overseas. This presents issues for customers such as the Swiss Bank, according to Koop: "We are a global bank, and we need coverage world-wide. We support our customer's globally. Very little of our travel is confined to the US." 6. Cost. Sending messages via whatever wireless service will still be more costly that sending them via long-distance telephone, almost every analyst and user agrees. But quantifying these costs is another matter. "We are glad to see RadioMail charging a fixed fee for usage, but how long will that last?" asked one user who is developing an application for a field-service force of over 1,000 users. 7. No single source for the total solution. The many different wireless solutions all have one thing in common: they all require products to work together from multiple vendors. Take RAM, for example. Mobidems are supplied from Ericsson, RadioMail (or Lotus or AT&T) for the software, and a fourth vendor provides the laptop or palmtop computer. Coordinating these many actors is not easy, not to mention troubleshooting problems. "The less integration we have to do, the better," says the Swiss Bank's Koop. 8. Lack of support by existing LAN OS vendors. Novell, Microsoft, IBM, and others have yet to consider how to support users who one day connect to the network in St. Louis and are next heard from in New York. These software vendors have not incorporated the tools or functions to enable users to move about the enterprise with ease. While efforts are underway at several of these vendors to support more mobile users, according to company product managers, these will still take some time to implement into their mainstream software products. -- D.S. ________________________________________________________________________ SIDEBAR 2: It's Only Physics: Determining Throughput Each of the three carriers claims their system has the best throughput, measured in terms of how long it takes to move a message or a file from the end-user's computer to its ultimate destination over the various radios and networks. Ardis claims its network supports 9,600 bps and this year has begun to upgrade a few of the connections to 19,200 bps, the speed CDPD carriers will initially implement. RAM claims 8,000 bps. However, these figures are more the maximum possible throughput and don't necessarily reflect actual user experiences. Wireless communications are very dependent on three things: packet size, available bandwidth, and the strength of the radio signals between the base station and the wireless modem. Only the first is a fixed and known entity. RAM uses 512 bytes, CDPD uses 114 byte packets. [check on Ardis packet size] The smaller the packet, the more overhead required and the longer the amount of time it takes to move data across the network. Bandwidth is a function of how many other users are competing for radio connections in a given geographic area, something that the networks monitor closely and fine-tune continuously. This is especially true for CDPD connections, which can only use idle time that is not being used to carry voice conversations on the cellular telephone network. Signal strength is tremendously site-specific, determined by the transmission power of the device, the physical proximity of the user's modem to the base station, and any obstacles in-between. Objects such as buildings or natural obstacles such as mountains and valleys can block signals, and other radios nearby can create interference. Both the devices supported by RAM and Ardis currently use two watts of power to transmit their signals. CDPD specifications call for a range of power from .6 watts to 3 watts, depending on the ultimate device manufactured -- this is similar to many cellular phones that can adjust their power requirements according to conditions. If all three items are working together, the maximum system throughput will be obtained. Otherwise, users will be faced with re-transmissions and throughput decreases. Consider the situation where a user is driving over a mountain and using his or her car phone. Cellular coverage can be spotty in these areas, and calls can be interrupted or even disconnected in these situations. So it is with wireless data, decreasing throughput from thousands of bps to a few bits per second trickle in these geographically undesirable locations. "Your signal strength can greatly affect how quickly you receive files and this depends greatly on your location," says Eric Rupert, a consultant who uses RAM and RadioMail. -- D.S. ________________________________________________________________________
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