WAP is an application protocol for providing communications
and connectivity to the Internet using digital mobile phones,
pagers, personal digital assistants, and other wireless devices.
It allows a user to navigate a text menu on his phone and click
on a menu item to select the next action.
Unlike other standards, however, the WAP standard was
not created by an industry consortium like the European
Telecommunications Standard Institute (ETSI) or
Telecommunications Industry Association (TIA). It began as
the idea of a small group of men with a vision at a company
called Libris. Out of that vision, a standard was born. Wireless
Application Protocol is based on a client–server architecture
much like that used on computers. Because of the complexity
and size of the cellular phone, a decision was made to place the
server on the back end.
The programming model for WAP as in Figure 2-7 consists
of a WAP Gateway and a Wireless Application Environment
(WAE) User Agent in the wireless device. Data flows from the
wireless device to the Gateway in encoded requests. These are
forwarded on to the Internet. The response, in the form of
Internet content, is returned to the Gateway where it is encoded
and forwarded to the User Agent in the wireless device.
Applications are written in Wireless Mark-up Language (WML)
and can reside on the WAP Gateway or an application server.
The Gateway converts protocols between message origins and
destinations. WAP also includes WMLScript and Wireless
Telephone Application Interface (WTAI). The script provides a
simple, yet fully functional programming language to run within
WML applications. WTAI is an interface to the telephone
functions of the device. For example, if you send a request to
directory assistance for a new restaurant that you want to try,
the phone number is sent to your user agent; by highlighting
and clicking Enter, the number is dialed automatically.
Libris developed a computer-generated prototype in early
1995 that was used to demonstrate WAP principles to potential
customers and investors. The key to getting WAP started
was buy-in from carriers and phone manufacturers. The Big
Three phone manufacturers—Motorola, Ericsson, and
Nokia—had to be convinced to drop proprietary plans and back
a standard-based proposal. Through relationships with some
key carriers like GTE and AT&T Wireless Services, Libris convinced
manufacturers to support the WAP initiative. The only
way for WAP to succeed was as an open standard: It could not
remain the sole property of its inventor and achieve widespread
usage. With a potential market of more than 1 billion cellular
phones by 2002, it was in the best interest of all manufacturers
to agree to standardization. By mid-1996 Libris changed its
name to Unwired Planet.
The first commercial server and browser software was
released in June 1996. During the next twelve months,
Unwired Planet collaborated with Ericsson, Motorola, and
Nokia to create the first WAP architecture, and published it on
the Internet in September 1997. Figure 2-8 shows some of the
WAP milestones.
A single focal point for WAP development, the WAP Forum,
was created in January 1998. The WAP Forum was created as
an open membership organization to promote Wireless
Application Protocol, write and issue new revisions to the WAP
standard, and to develop a quality-assurance function to verify
compatibility issues between members. In May 1998, the WAP
Forum released the first, open-version WAP 1.0 specifications.
WAP, however, has not been an instant success. The biggest
complaint about WAP is that it required the Internet community
to rewrite sites to support WAP. WAP proponents are quick
to point out, however, that the mobile phone is an entirely different
user interface compared to the typical Internet application.
The display is much smaller and the keypad lacks the full
alphanumeric keyboard that computer users enjoy. It should
not be expected that Internet content could appear the same
on a phone as on a computer monitor. Internet content must
be optimized for presentation to the phone and that presented
the next big challenge—getting application developers to commit
to WAP development.
Another problem common to WAP is inconsistent adherence
to the WAP standard—every phone seems to behave differently
and support different features. This occurs not only
between manufacturers, but between different phones of the
same manufacturer. One phone may center-justify text and the
next ignores all text justification. Displays vary in size and the
number of characters or lines, creating a different look to every
phone. A common mistake in WAP design is to include too
many nested menus for navigation. Better user interfaces and
larger displays and easier-to-use keypads must be created to
improve adherence to the standard.
To prevent wars between rivals, proponents of WAP have
agreed to make XML (Extensible Markup Language) WAPcompliant.
The expectation is that WAP will merge with another
popular application protocol, i-Mode, to become Extensible
Hypertext Markup Language (XHTML). An example of WML
is illustrated in Figure 2-9.
Wireless Application Protocol is a major player in the
microbrowser market. It was first launched in Europe, where
consumers already enjoyed SMS on GSM networks.
Competition was tough in Europe, however—although WAP
was launched, there was a shortage of WAP-enabled phones.
Content was lacking and no two phones worked or displayed
WAP the same. A running joke in Europe described WAP as
standing for “Where Are the Phones?” Despite everything,
Europe is estimated to have over 16 million WAP subscribers.
In the United States, the situation is even worse. Not only is
there a shortage of WAP phones and applications, but TDMA
carriers never deployed WAP gateways because of delays in getting
licensing from manufacturers. Meanwhile, in Japan, WAP
is deployed on CDMA phones that compete directly with i-
Mode. Japanese sources estimate that there are about 6 million
WAP users compared with over 20 million i-Mode subscribers.
One important distinction should be made between today’s
WAP phones and next-generation phones. Until recently the
current generation of standards could only support circuitswitched
connections. Packet data on digital networks did not
exist. Just like CDPD, these phones remained on a dedicated
channel assignment as the user browsed the WAP application.
The launching of GPRS in the GSM world enabled the first
packet-data network.
Wireless Application Protocol will continue to exist but the
big question is “in what form?” Many industry experts believe
that the window of opportunity is closing on WAP. The WAP
Forum is a large and strong industry body, however, and a great
deal of investment has already been made in WAP. The industry
will continue to launch the technology wherever there is a
possibility to create new revenue streams for all.