Page 87 - DCAP512_WAP_AND_WML

Unit 6: Card Navigation

Internet standards such as hypertext markup language (HTML), HTTP, TLS and transmission Notes
control protocol (TCP) are efficient over mobile networks, requiring large amounts of mainly
text-based data to be sent. Standard HTML content cannot be effectively displayed on the small-
size screens of pocket sized mobile phones and pagers. WAP utilizes binary transmission for
greater compression of data and is optimized for long latency and low bandwidth. WAP sessions
cope with intermittent coverage and can operate over a wide variety of wireless transports.
WML and wireless markup language script (WML Script) are used to produce WAP content.
They make optimum use of small displays, and navigation may be performed with one hand.

!
Caution WAP content is scalable from a two-line display on a base device to a full graphic
screen on the latest phones and communicators.

The lightweight WAP protocol stack is designed to minimize the required bandwidth and
maximize the number of wireless network types that can deliver WAP content. The aim is to
support WAP on multiple networks. These include:

 Global System for Mobile communications (GSM) 900, 1800, 1900 MHz
 Digital European Cordless Communication (DECT)
 Time Division Multiple Access (TDMA)

 Personal Communication Service (PCS)
 FLEX
 Code Division Multiple Access (CDMA)
All network technologies and bearers will also be supported, including short message service
(SMS), USSD, circuit-switched data (CSD), cellular digital packet data (CDPD), and general packet
radio service (GPRS). As WAP is based on a scalable-layered architecture, each layer can develop
independently of the others keeping WDP constant. This makes it possible to introduce new
bearers or to use new transport protocols without major changes in the other layers.

Self Assessment

Fill in the blanks:

9. The <do> element is used to associate a task to a certain user interface element of a
………………………
10. Tasks such as <go>, ……………………… and <refresh> are enclosed in the <do></do>
tags.
11. The ……………………… element is usually the left softkey in mobile phone browsers,
since the left softkey is used as the “Yes” or “OK” softkey typically.
12. WAP utilizes ……………………… for greater compression of data and is optimized for
long latency and low bandwidth.

6.5 Types of WML Cards

WML pages are structured within “decks,” allowing several pages (“cards”) to be defined in
each WML file. This deck analogy allows multiple pages to be delivered to the mobile client at
the same time, minimizing the loading time between related pages. However, the limited
memory on most devices constrains the deck size, usually to less than 1024 bytes. Therefore,

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