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What is WAP
WAP (Wireless Application Platform) - an optimized application protocol developed by a consortium (Nokia, Ericsson, Phone.Com and others) to allow access
to the Internet applications from smart phones, PDAs, Windows CE compatible and similar handheld devices. It utilizes HDML
(Handheld Data Markup Language - subset of HTML) and a small foot-print browser. HDML essentially avoids graphics
and sends only required data stream to the device that these devices can display.
Mobile Internet is all about Internet access from mobile
devices. Well, it’s true, but the ground realities are different. No doubt Internet has grown fast, well really fast!
but mobile Internet is poised to grow even faster. The fundamental difference lies in the fact that whereas academics and
scientists started the Internet, the force behind mobile Internet access is the cash-rich mobile phone industry. Mobile industry
has always been looking for more avenues to make more money and in this attempt, the mobile industry besides carefully finding
about the needs and requirements for a mobile data user is also creating new demand patterns also. What makes things even
more favorable for the mobile Internet is that it already has a lot of Internet-based content from which to draw. This can
be adapted for display on mobiles in a number of ways. A website can be viewed using a phone that is WAP-enabled.
A mobile is something that we
take along with us where ever we go (unlike our computers) and that is one of the reasons many analysts believe that within
three years more people will be accessing the Internet from mobile phones than from office or home computers.
Well, a variety of mobile wireless
standards exist today, each have different levels of data capabilities. Thanks to the developments taking place in all the
2nd generation mobile wireless data technologies, and the high data speeds being promised by the 3rd generation systems, the
distinction between the wireless, wireline and the Internet service providers is beginning to blur. Mobile Internet access
surely is poised to be a major commercial success. While the underlying network technologies keep on evolving, what is going
to differentiate on network from the other is finally the services that it provides to the end user. Data services provided
by the mobile networks are fast becoming popular and in some countries in Europe people are spending more on mobile data access
compared to voice services. This presents a huge opportunity for the mobile data service developers.
The issue is that with a range
of mobile devices and underlying mobile wireless technologies, developing services specific to each type of equipment and
specific to a particular technology is troublesome. An application written for specific equipment and a specific technology
won’t work anywhere else. This calls for a standardization, which provides a generic model where applications can be
written without keeping in mind the equipment and the technology. On the equipment side, the wireless devices represent the
ultimate constrained computing device with:
Less powerful CPUs,
Less memory (ROM and RAM)
Restricted power consumption
Different input devices (e.g.,
a phone keypad, voice input, etc.)
and on the network side, wireless networks are constrained
Less connection stability
Less predictable availability
However, most important of all,
wireless subscribers have a different set of essential desires and needs than desktop or even laptop Internet users. With
the emergence of 3G technologies, the constraint on the low data rates may not be as limiting as it is today but is must be
understood clearly that, as bandwidth increases, the handset’s power consumption also increases which further taxes
the already limited battery life of a mobile device. Therefore, even as wireless networks improve their ability to deliver
higher bandwidth, the power availability at the handset will still limit the effective throughput of data to and from the
device. A wireless data solution must be able to overcome these network limitations and still deliver a satisfactory user
Short for the Wireless Application Protocol, a secure specification that allows users to
access information instantly via handheld wireless devices such as mobile phones, pagers, two-way radios, smartphones and
WAP supports most wireless networks.
These include CDPD, CDMA, GSM, PDC, PHS, TDMA, FLEX, ReFLEX, iDEN, TETRA, DECT, DataTAC, and Mobitex.
WAP is supported by all operating systems. Ones specifically engineered for handheld devices
include PalmOS, EPOC, Windows CE, FLEXOS, OS/9, and JavaOS.
that use displays and access the Internet run what are called microbrowsers--browsers with small file sizes that can accommodate
the low memory constraints of handheld devices and the low-bandwidth constraints of a wireless-handheld network.
Although WAP supports HTML and XML, the WML language (an XML application) is specifically
devised for small screens and one-hand navigation without a keyboard. WML is scalable from two-line text displays up through
graphic screens found on items such as smart phones and communicators.
and CPU power because it does not contain many of the unnecessary functions found in other scripting languages.
Because WAP is fairly new, it is not a formal standard yet.
It is still an initiative that
was started by Unwired Planet, Motorola, Nokia, and Ericsson.
HOW WAP WORKS
You and millions of other people around the world use the Internet every day -- to
communicate with others, follow the stock market, keep up with the news, check the weather, make travel plans, conduct business,
shop, entertain yourself and learn.
Staying connected has become so important that it's hard to get away from your computer
and your Internet connection because you might miss an e-mail message, an update on your stock or some news you need to know.
With your business or your personal life growing more dependent on electronic communication over the Internet, you might be
ready to take the next step and get a device that allows you to access the Internet on the go.
That's where wireless Internet comes in. You've probably seen news or advertising about
cell phones and PDAs that let you receive and send e-mail. This seems a logical next step, but there are some questions that
come up when you think about going mobile with the Internet. Will you still be able to surf the Web?
How fast will you be able to get
the information you need? You might have heard of the Wireless Application Protocol (WAP) and wonder how it works. Learn just
what WAP is, why it is needed and what devices use it.
the most important factor in the birth of wireless Internet has been the proliferation of digital cell phones in the last
few years. The expanding network of digital cellular and personal communication services (PCS) has created a solid foundation
for wireless Internet services.
It is estimated that there are more than 50 million Web-enabled cell phones in use. In 1997, Nokia, Motorola, Ericsson
and Phone.com came together to create the WAP because they believed that a universal standard is critical to the successful
implementation of wireless Internet. Since then, more than 350 companies have joined them in the WAP Forum.
Making a Web site accessible through a wireless device is quite a challenge. So far, only
a small portion of the more than a billion Web sites provide any wireless Internet content. As the use of WAP-enabled devices
grows, you can expect that many more Web sites will be interested in creating wireless content.
WAP is designed to work on any of the existing wireless services, using standards such as:
Short Message Service (SMS)
High-Speed Circuit-Switched Data (CSD)
Packet Radio Service (GPRS)
Unstructured Supplementary Services
Wireless Markup Language
uses Wireless Markup Language (WML), which includes the Handheld Device Markup Language (HDML) developed by Phone.com.
WML can also trace its roots to
eXtensible Markup Language (XML). A markup language is a way of adding information to your content that tells the device receiving
the content what to do with it. The best known markup language is Hypertext Markup Language (HTML). Unlike HTML, WML is considered
a meta language.
Basically, this means that in addition to providing predefined tags, WML lets you design your own markup language
components. WAP also allows the use of standard Internet protocols such as UDP, IP and XML.
There are three main reasons why
wireless Internet needs the Wireless Application Protocol:
Most cell phones and Web-enabled
PDAs have data transfer rates of 14.4 Kbps or less.
Compare this to a typical 56 Kbps modem, a cable modem or a DSL connection.
Most Web pages today are full of
graphics that would take an unbearably long time to download at 14.4 Kbps. Wireless Internet content is typically text-based
in order to solve this problem.
The relatively small size of the LCD on a cell phone or PDA presents another challenge.
Web pages are designed for a resolution of 640x480 pixels, which is fine if you are reading on a desktop or a laptop.
The page simply does not fit on
a wireless device's display, which might be 150x150 pixels.
Also, the majority of wireless devices use monochrome screens. Pages are harder to read
when font and background colors become similar shades of gray.
Navigation is another issue. You
make your way through a Web page with points and clicks using a mouse; but if you are using a wireless device, you often use
one hand to scroll keys.
WAP takes each of these limitations into account and provides a way to work with a typical wireless device.
Wireless Application Protocol
what happens when you access a Web site using a WAP-enabled device:
You turn on the device and open the minibrowser.
The device sends out a radio signal, searching for
connection is made with your service provider.
You select a Web site that you wish to view.
A request is sent to a gateway server using WAP.
The gateway server retrieves the
information via HTTP from the Web site.
The gateway server encodes the HTTP data as WML.
The WML-encoded data is sent to your device.
You see the wireless Internet version
of the Web page you selected.
To create wireless Internet content, a Web site creates special text-only or low-graphics
versions of the site.
The data is sent in HTTP form by a Web server to a WAP gateway. This system includes the WAP encoder, script compiler
and protocol adapters to convert the HTTP information to WML. The gateway then sends the converted data to the WAP client
on your wireless device.
What happens between the gateway and the client relies on features of different parts of the WAP protocol stack.
Let's take a look at each part of the stack:
- The Wireless Application Environment holds the tools that wireless Internet content developers use.
These include WML and WMLScript,
which is a scripting language used in conjunction with WML.
WSP - The Wireless Session Protocol determines whether a session between the device and
the network will be connection-oriented or connectionless.
What this is basically talking about is whether or not the device needs to talk back and
forth with the network during a session. In a connection-oriented session, data is passed both ways between the device and
the network; WSP then sends the packet to the Wireless Transaction Protocol layer (see below).
If the session is connectionless,
commonly used when information is being broadcast or streamed from the network to the device, then WSP redirects the packet
to the Wireless Datagram Protocol layer (see below).
WTP - The Wireless Transaction Protocol acts like a traffic cop, keeping the data flowing
in a logical and smooth manner.
It also determines how to classify each transaction request: Reliable two-way Reliable one-way
Unreliable one-way The WSP and WTP layers correspond to Hypertext Transfer Protocol (HTTP) in the TCP/IP protocol suite.
WTLS - Wireless Transport Layer
Security provides many of the same security features found in the Transport Layer Security (TLS) part of TCP/IP. It checks
data integrity, provides encryption and performs client and server authentication.
WDP - The Wireless Datagram Protocol works in conjunction
with the network carrier layer (see below).
WDP makes it easy to adapt WAP to a variety of bearers because all that needs to change
is the information maintained at this level.
Network carriers - Also called bearers, these can be any of the existing technologies that
wireless providers use, as long as information is provided at the WDP level to interface WAP with the bearer.
Once the information is received
by the WAP client, it is passed to the minibrowser. This is a tiny application built into the wireless device that provides
the interface between the user and the wireless Internet.
The minibrowser does not offer anything more than basic navigation. Wireless Internet is
still a long way from being a true alternative to the normal Internet. It is really positioned right now for people who need
the ability to connect no matter where they are.
The WAP Forum is continually working on the specifications of the WAP standard to ensure
that it evolves in a timely and useful manner.