The Wireless Application Protocol (WAP) is an application environment and a
set of communication protocols for wireless devices. It is designed to enable
access to the Internet and advanced telephony services. This access is
independent of manufacturer, vendor, and technology.
WAP bridges the gap
between the mobile world and the Internet or corporate intranets. It gives
pocket-sized mobile device users access to the same information that they can
access from their desktops.
WAP is a global standard that is not
controlled by any single company. Ericsson, Nokia, Motorola, and Unwired Planet
founded the WAP Forum in 1997. There are now over one hundred members. The WAP
specifications define a set of protocols for the application, session,
transaction, security, and transport layers.
WAP also defines a wireless
application environment (WAE), which enables operators, manufacturers, and
content developers to create advanced differentiating services and
applications. Types of applications include micro-browsers, scripting
facilities, e-mail, WWW-to-mobile messaging, and mobile-to-telefax access.
WAP utilizes Internet standards such as XML, UDP, and IP. Many of the WAP
protocols are based on Internet standards, such as HTTP. The WAP protocols have
been optimized for the unique constraints of the wireless environment, which
include low bandwidth, high latency, and less connection stability. Standard
HTML content cannot be effectively displayed on the small screens of
pocket-sized mobile devices.
The lightweight WAP protocol stack shown in
Figure
is designed to
minimize the required bandwidth and maximize the number of wireless network
types that can deliver WAP content. Multiple networks will be targeted,
including GSM, TDMA, PCS, and CDMA. All network technologies and bearers will
also be supported, including short message service (SMS), circuit-switched
cellular data (CSD), cellular digital packet data (CDPD), and GPRS.
WAP
content is converted into a compact binary form known as a byte code for
transmission over the air. The WAP micro-browser software interprets the byte
code and displays the interactive WAP content.
The WAP browser may do
for the mobile Internet, what the Web browser did for the Internet. Over 75
percent of the leading mobile device manufacturers in the world are involved in
the WAP Forum and have announced WAP-compatible devices. Web browsing is not
expected to be the main selling factor for WAP. Real-time applications and
services that supply important pieces of information are expected to promote
the success of WAP. Examples include stock prices, weather, and restaurant
locations.