|By Sergey Ruseev||
|October 5, 2000 12:00 AM EDT||
The rapid expansion of wireless access technologies, the implantation of the Internet into all spheres of human activity, and the pressure of mobile communication markets - these factors represent the development of wireless services.
Standards for mobile communications have been developing rapidly in the last few years. The sequential appearance of analog (AMPS, NMT-450) and digital standards (GSM, D-AMPS, DCS), and their gradual movement to a universal standard, resulted in the formation of mobile communications companies all over the world. A new community of wireless subscribers is being created.
New services, like roaming and data transfer, formed the basis for the globalization of services provided. Mobile subscribers need data availability. This is now possible due to wireless applications that have been developed based on standards that are applicable for any type of wireless carrier.
It's impossible to overestimate the penetration of the Internet into all areas of human activity; it's become the environment of information distribution and storage. The Internet is also a fast-growing business media. During the past 10 years Internet technologies have progressed greatly. Now there are several typical solutions in the fields of access authorization, database publication, remote monitoring and Internet services integration to Web servers.
To save investments, developers want to get maximum usage and create new usage for existing technologies.
Market pressure is also a major influence. For example, there are more than 100 million Internet users, but the number of cellular network subscribers is more than double that number. Another example, the coefficient of penetration into the PC market (principal users of the Internet) is much lower than the one for cellular set owners - even in the U.S., a very computer-oriented country. So the Internet services and features that are required beyond the bounds of the Internet community already have a huge audience.
The wireless application protocol (WAP) specification is one of the main technologies in wireless applications - the software that's based on the specification. The main technology components are the WAP browser, WAP gateway and WAP server (in its turn, it may consist of HTTP, and application and database servers). A detailed description of all WAP-specification peculiarities is beyond the limits of the article.
- WAP Browser: Usually it's a built-in wireless terminal, but in certain cases it may be executed as loaded software (Palm Pilot).
- WAP Gateway: Used as an intermediary between the WAP client and the HTTP server, it adapts the data that's received by HTTP queries from the WAP server to specialties of transmission environment within the cellular communication network. Common restrictions to the environment are:
- Connection instability
- Considerable service activation time
- Limited rate of data transmission to the cellular terminal
- Limited memory of the cellular terminal
- Limited calculating capacity of the cellular terminal
- Limited possibilities of information and graphical representation on the cellular terminal
- Truncated capacities of information input
- WAP Server: Includes the HTTP server of the WML content, the database server, and the application server as a binder element.
ColdFusion as a WAP Application Server
The basic requirements for the development of wireless application software are:
- Development simplicity: The high dynamics of new services imply a simple method for their creation and modification. A program interface that allows developers to use their acquired skills when developing applications is also required.
- Wide integration: Databases, Internet services, Web servers on the Net, and the phone services of cellular companies are indispensable for their dynamic content. The means for wide integration are contained in ColdFusion at the necessary level of tag development. A number of tags have already been created - some available free of charge. It's also possible to create tags independently. For example, to select and publish a recordset of two linked tables from the database, write some statements in CFML. To send this set as an e-mail, you need three more lines; to design the result as an XML set - one more line.
- Interoperability: Usually reached by using a WAP compatible browser that can interpret WML v.1.1. With ColdFusion it's possible to adapt WML contents to a specific cellular terminal type. To carry this out, a user variable that stores data on a terminal and a microbrowser type are analyzed.
- Independence on the cellular communication standard: Usually obtained by the WAP interface adjustment, it's an essential property of the WAP application.
- Personalized user interface: The CF developer may personalize the data published on request. The various possibilities of customizing WML page generation relies on client variables.
- Strong security: There are several levels of data protection. The basic ones are encoding and both database and application access control.
- Portability: CF is available on all widespread hardware platforms. The software operates under Windows 95/98, Windows NT, Sun Solaris, HP UX, Linux and BSDI. There are also free versions of CF Express with limited functionality.
- Price: CF version 4.5 costs $1,500, and doesn't depend on a concurrent number of users.
Wireless Application Sample Pilot by Peter Service, Ltd.
The scheme of a wireless application that demonstrates the main features of the ColdFusion application server is shown in Figure 1.
This approach is realized on http://wap.billing.ru and http://wap.nwgsm.com. We used WAPLITE gateway from Infinity Technologies (www.waplite.com) in the production mode for all our wireless solutions. Full-range WTLS-enabled applications for the corporate market are supported. In addition, WAPLITE gives the best solution for middle-sized wireless carriers worldwide.
A sample staff list from a wireless carrier involved in WAP is described below:
- The manager marks data on the current number of cellular company subscribers using a WAP interface. This data modification should always be controlled.
- The customer service employee enters the data into a specified DB table. After data has been marked, the session is terminated and the subscriber is transferred to waiting mode.
- The CF application dispatcher starts up the tracking application (frequency is set by the user) that checks the parameter that indicates changes in the DB table. If the variance value exceeds the quantum specified, then a request-on-notification will be sent via three gateways - e-mail, HTML/SMS and HTML/pager.
The application server may also appear as a mediation device that realizes the initial processing of Call Data Record (CDR) from the WAP gateway.
At last, all features that are related to displaying database contents on a cellular terminal may be published via the same Web server using practically the same application server modules.
Figure 2 shows a demo variant of a WAP interface for a cellular network subscriber that allows (after authorization) modification of the service status. Next to this one, a variant of a similar interface on a cellular communications operator's Web server is shown for comparison.
The CF application server realizes several integration levels:
- Interaction with a WAP gateway on receipt of the CDR acting as a mediation device
- Interaction with active regional wireless networks
- Interaction with Internet services
- Application for protection from unauthorized access
- Establishing a session with a WAP terminal and access authorization
- Establishing a session with a visitor who orders services in standard HTML using a standard Web browser.
Allaire's CF application server allows you to create new services for cellular communications operators and corporate customers, to scale these applications as well as adapt them to new conditions. It enables the wide integration that's required by wireless applications for cellular operators, public Internet services and service providers, and corporations.
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