Page 125 - DCAP311_DCAP607_WIRELESS_NETWORKS

Unit 7: Wireless LAN

Goals Notes
The utility's work and inventory management application is MAXIMO*, a system that
uses an Oracle database, developed by PSDI (Bedford, MA, http://www.psdi.com/).
Since MAXIMO is developed for specific types of job functions, it can be considered a
vertical market-type application. From the point-of-view of providing wireless access to
an enterprise database, however, it is similar to any number of other applications based
on SQL (Structured Query Language), one of the most common protocols used today for
client/server applications.
The office-based applications that the utility intends to extend to the field include Novell's
GroupWise* and Web-hosted applications on the utility's intranet. These are horizontal
market applications in that their use is not restricted to any particular job function or type
of industry. In addition, the utility plans to make a GIS (graphical information system)
available eventually, though it realizes that current wireless networks are not well-suited
for such intensive graphical content. The goal for all these applications is to provide reliable
remote operation with preferably the same user interface as a direct LAN connection.
Though slower response times are acceptable and somewhat inevitable, applications must
operate in a reliable and effective manner.
The utility has two types of remote workers who will use the wireless system: leads that will
use MAXIMO primarily and crew chiefs that will use the office applications in addition to
MAXIMO. Because it is difficult to predict what applications may be needed in the future,
a key goal is to provide a flexible wireless architecture that allows new applications to be
added easily.
Another goal is security. Wireless connections should be no less secure than existing
remote access methods based on dial-up connections. Finally, while the utility is willing to
commit to a particular wireless technology in its initial deployment, it wants an approach
that allows it to migrate easily to other wireless technologies in the future.
Choosing the Computing Platform
The utility recently adopted the Microsoft Windows* 95 platform across multiple
departments. For the wireless IP project, it needed to decide whether to use Windows
95 notebook computers or to consider a somewhat more specialized platform such as
Windows CE.
Though MAXIMO client software is not available for Windows CE, Windows CE was an
option because Syclo Corporation (Barrington, Illinois) supplies middleware that enables
Windows CE computers to access MAXIMO databases through a gateway. Using Windows
CE would have provided advantages such as lower device cost, greater portability and
longer battery life.
Despite some of the advantages of Windows CE, the utility was concerned about the range
of applications it could deploy on the platform. Because the utility expects the requirements
for mobile workers to evolve over time, and for the types of work performed in the field to
expand, it needs the greatest degree of flexibility possible for the types of applications it can
deploy. For this overwhelming reason, the utility chose Windows 95 over Windows CE.
In addition, because the computers are mounted in the vehicles and not used outside the
vehicles, the extra portability Windows CE was not a factor. Finally, there are a number of
ruggedized laptops available that can address the demanding field conditions that utility
workers encounter.
Choosing the Wireless Network
The utility faced a bewildering situation when it began evaluating the wireless networks
available. There was the analog cellular network, new digital cellular and PCS technologies,
and four wireless packet networks with service in the Seattle area.
Contd...

LOVELY PROFESSIONAL UNIVERSITY 119