WAP Development - Wireless deliveryby Aswathi P P (Software Programmer, Excellone Technologies)
WAP the new Avenue Wireless Application Protocol
(WAP), the standard moulded and nurtured by the WAP forum (Nokia,
Ericsson, and Phone.com & Motorola) supplies a uniform technology
platform with consistent content format for delivering Internet
and Intranet based information and services to digital mobile phones
and other wireless devices. WAP development facilitates easy and
fast rendering of needed information and services to mobile users.
According to the WAP development forums official
definition, WAP is, The de-facto worldwide standard for providing
Internet communication and advanced telephony services on digital
mobile phones, pagers, personal digital assistants and other wireless
terminals
Basically WAP is designed to make customer-friendly
and fresh data applications for mobile phones. Three types of terminals,
in use have been defined
- Featured phone, which offers high voice quality with the capability
of text messaging and Internet browsing.
- Smart phones with similar function along with large display.
- The Communicator, an advanced terminal for mobile professional
similar in size to a palm top with a larger display.
The WAP forum had set the following goals for WAP
- Independent wireless network standard.
- Open to all Internet users
- Proposed to the appropriate web standard bodies.
- Scalable across transport options.
- Scalable across device types.
- Extensible overtime to new networks and transports.
The WAP development forum has also made WAP accessible
to GSM - 900, GSM 1800, GSM 1900, CDMA IS 95, TDMA IS 136,
3G systems IMT 2000, UTMS, W-CDMA Wideband IS 95.
WAP services in actual scenario
In the actual business scenario, services of WAP
development can be adopted for transferring information. WAP development
can provide its services by using inexpensive devices with built
in barcode scanners, keypads and simple digital display. WAP allows
a suite of client application to be built which reuses existing
server applications and database. Further more, these applications
can be dynamically downloaded and run on any of these devices. Wireless
application in every industry will certainly need WAP services.
Coming to the grass root level, this is how a WAP service works.
- The client makes a request.
- The WAP gateway receives the clients request (which is received
by a WAP gateway).
- The request is processed and formulated using WML and the result
is back to the client.
Communication between the client and the server
through these layers, Wireless Application Environment (WAE), Wireless
Session Protocol (WSP), Wireless Transaction Protocol (WTP), Wireless
Transport Layer Security (WTLS), Wireless Data gram Protocol (WDP),
Beares (GSM, IS - 136, CDMA, GPRS, CDPD etc.).
Communications Between Client and Server
The WAP development Protocol Stack is implemented
via a layered approach, which is similar to the OSI network model.
The different layers are,
- Wireless Application Environment (WAE)
- Wireless Session Protocol (WSP)
- Wireless Transaction Protocol (WTP)
- Wireless Transport Layer Security (WTLS)
- Wireless Datagram Protocol (WDP)
- Bearers (GSM, IS-136, CDMA, GPRS, CDPD, etc.)
According to the specifications for WAP development,
WSP offer means to provide functionality, extensible request - reply
methods, composite objects, content type negotiation, exchange client
and web server session headers, interrupt transactions in process
and push content from web server to client in an unsynchronized
manner, negotiate support for multiple, simultaneous and asynchronous
transactions.
Further more it specifies, that WAP the protocol
that allows for interactive web browsing applications supports three
transaction classes.
- Unreliable with no result message,
- Reliable with no result message and
- Reliable with one reliable result.
WTP also defines the transaction environment in
which clients and servers interact and exchange data.
WTLS that provide security is based on SSL and
TLS.
WDP layers, allow applications to operate transparently
over varying bearer services.
The Wireless Mark up Language (WML) is, in fact,
an XML document type defined by a standard XML Document Type Definition,
or DTD.
WMLScript facilitates client side procedural logic
which is based on ECMA script based on Java script language.
WMLScript is a case-sensitive language that supports
the standard variable declarations, function and other common constructs
such as if-then statements and for / while loops. Among the standards
more interesting features are the ability to use external compilation
(units via the use url pragma), access control (via the access pragma)
and a set of standard libraries defined by the specification including
the Lang, Float, String, URL, WML Browser, and Dialogs libraries.
WAP Forum
The team behind WAP development is the WAP forum
founded by Nokia, Ericsson, Phone.com & Motorola. Now the software
giants like Microsoft, Oracle, IBM & Intel have joined hands with
the forum along with hundreds of others.
These huge supports are one of the greatest strengths
of WAP development. WAP's approach to content distribution and the
way of distributing contents to remote devices using inexpensive,
standardized client software is also adding to its popularity. WAP
technologies, which rely on back-end service to handle user authentication,
database queries, intensive processing and the usage of mark up
languages derived from SGML for delivering content to client, may
all have positively affected it.
WAP development being an extremely novel technology,
is gaining increasing popularity. WAP has the image of a powerful
tool for software developers.
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