a) DEFINITION AND SCOPE
WAP stands for Wireless Application Protocol. WAP links devices with small displays such as cordless or corded phones to the Internet and enables information display on small screens. WAP was evolved mainly to combat slow data transmission and enable smaller displays. Initially it was used in mobile phones and then the technology migrated to cordless and corded phones.
There are two general versions of WAP protocol, WAP1.x and WAP2.x.
WAP1.x is useful for retrieving condensed short information such weather reports, news headlines, business quotes, sports results, entertainment etc. WAP is convenient in terms of providing the information from the Internet without the user having the need to connect to a PC and the Internet.
There have been user reservations about the speed of retrieving information using WAP technology. This is mainly to do with the network rather than WAP. The GSM network used by WAP is slow in terms of data transmission (9.6 Kbps). The scene has changed with the introduction of GSM?s General Packet Radio Service (GPRS). Speed 3 to 12 times higher can be expected.
When WAP is used over a fixed network connection, transmission rates more than 5 times faster as compared to GSM can be achieved which allows instant information retrieval with the cost of a key click and a satisfactory WAP user experience.
b) WAP OPERATIONS
WAP technology is similar to the way in which the Internet works on the PC. Basically the Internet utilizes two types of computers: servers and clients. Servers are the computers that host the pages that the user views. The clients are the computers from which these pages are viewed. The differences are:
The Internet is accessed from the phone instead of the computer. The phone becomes the client and the servers remain the same that host the pages the user views. Between the server and the client is the WAP Gateway. A WAP Gateway is an intermediary between the Internet and the network on which it is accessed. It converts the WAP request into a Web request when information is sent from the telephone to the Internet and from Web to a WAP request when information is sent back from the Internet to the telephone.
The web site that is being viewed must be presented to the terminal in WAP format. Today Web pages are written using many reach capabilities of the HTML (Hyper Text Mark up Language), which can prove to be too complex for mobile phones with slower operating speeds and small screens. The mark up language used by WAP is WML (Wireless Mark up Language) which simplifies down load time and presentation. The web site presentation takes into account display size and the business model supporting the WAP service.
The viewing device should be WAP enabled, that is the device must understand the WAP protocol and be able to display the information. Similar to the HTML browser in a PC, the telephone needs a (mini) WAP browser to display the WML.
To retrieve information from the WAP enabled terminal, connection between the terminal and the WAP service provider is required similar to the dial up modem required to access the Internet with the PC. The user can make a request by activating a combination of buttons on the terminal that will initiate special WAP protocol exchange activities. The WAP protocol exchange will utilize a selected bearer for the transmission, e.g. SMS, GPRS, USSD, UDP/IP, i.e. the WAP protocol data units will be encapsulated into the protocol data units of one of the bearer types and sent over the network in use. After the connection with the service provider is established, using the mini browser, the user will select the web site to be viewed and the request will be received by the WAP Gateway. The WAP Gateway will retrieve the information from the Internet using the normal HTTP way, will encode the data as WML, and send it to the user terminal which in turn will display it on its screen.
