2. 2
Mention the devices for which WAP is designed.
The devices for which WAP is designed are
mobile phones, pagers, PDAs
Devices with limited CPU, memory and battery life
Devices with simple user interface
Low bandwidth and high latency environments
Unpredictable availability and stability
1. Why HTTP, TLS and transmission control protocol (TCP) are inefficient over mobile
networks?
Internet standards such as hypertext markup language (HTML), HTTP, TLS
and transmission control protocol (TCP) are inefficient over mobile networks because they require
large amounts of mainly text-based data to be sent over a network. This requirement for large amounts
of data to be transmitted is not optimal for mobile networks because mobile networks
currently are characterized by lower bandwidths then normal web networks. In addition, any protocols
with large data transmission requirements must overcome the difficult challenge of intermittent
coverage, another characteristic of wireless networks
2. What are the goals of WAP architecture?
The goals of the WAP architecture are as follows.
Provide a web-centric application model for wireless data services that utilizes the telephony,
mobility, and other unique functions of wireless devices and networks while allowing maximum
flexibility as well as ability for vendors to enhance the user experience.
Enable the personalization and customization of the device, the content delivered to it, and the
presentation of the content.
Provide support for secure as well as private applications and communication in a manner that is
consistent and interoperable with Internet security models.
3. 3
Enable wireless devices and networks that are currently or in the near future being deployed,
including a wide variety of bearers from narrowband to wide-band.
Provide secure access to local handset functionality.
Facilitate network-operator and third party service provisioning.
Define a layered, scalable and extensible architecture.
Leverage existing standards where possible, especially existing and evolving Internet standards.
WAP architecture provides layered design of the entire protocol stack. Each of the layers of the
architecture is accessible by the layers above, as well as by other services and applications.
3. What are the differences between HTML and WML?
Major difference between HTML and WML is that the basic unit of navigation in HTML
is a page, while that in WML is a card. A WML file can contain multiple cards and they form a deck.
When a user goes to a WAP site, the mobile browser loads a WML file that contains a deck of cards
from the server. Only one card will be shown on the screen of the wireless device each time. If the user
goes to another card of the same deck, the mobile browser does not have to send any request to the
server since the file that contains the deck is already stored in the wireless device.
WML is designed in this way because wireless devices have a high latency for connecting to the server.
Downloading a deck of cards at a time can lower the number of round trips to the server. You can put
links, text, images, input fields, option boxes and many other elements in a card.
4. Explain the use of type attribute.
The type attribute is another useful attribute of the <input> element. Its value can be either text
(default value) or password. If the value of the type attribute is text, the characters in the input field will
be visible; if you change it to password, all characters in the input field will be displayed as asterisks
(*). Note that data in password input fields will not be transmitted in a more secure way than that in
ordinary input fields.