WAP Technology


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  • Sessions by WSP – Sessions are assumed to be long-lived, so problem of lost connections is addressed by allowing lost sessions to be resumed even when dynamically assigned IP addresses are used
    Since no connection is set up, the effects of lost connections and other times of inactivity are minimized
    The unpredictable nature of wireless connection means that small segments of message are often lost
    Selective retransmission – meaning that only lost segments arev retransmitted and not the entire message as in TCP
    Card - is a single unit of interaction with the end-user, such as a text-screen, a selection list or a combo of these.
    A card is typically small enuff to be displayed on a small screen
    DECK – Series of cards used for making an application
  • WAP Technology

    1. 1. WAP Mrs. Vasanthi Muniasamy
    2. 2. WHAT IS WAP? WAP is Wireless Application Protocol WAP is an open international standard for application layer network communications in a wireless communication environment. Its main use is to enable access to the Internet (HTTP) from a mobile phone or PDA.
    3. 3. WHAT IS PROTOCOL? A Protocol is a set of guidelines or rules. In computing and internet
    4. 4. FEATURES OF WAP          WAP stands for W ireless A pplication P rotocol WAP is an application communication protocol WAP is used to access services and information WAP is inherited from Internet standards WAP is for handheld devices such as mobile phones WAP is a protocol designed for micro browsers WAP enables the creating of web applications for mobile devices. WAP uses the mark-up language WML (not HTML) WML is defined as an XML 1.0 application
    5. 5. WAP Micro Browsers    To fit into a small wireless terminal, WAP uses a Micro Browser. A Micro Browser is a small piece of software that makes minimal demands on hardware, memory and CPU. It can display information written in a restricted mark-up language called WML. The Micro Browser can also interpret a reduced version of JavaScript called WMLScript.
    6. 6. COMPONENTS OF WAP WML   WML stands for W ireless M arkup L anguage. It is a mark-up language inherited from HTML, but WML is based on XML, so it is much stricter than HTML. Differs from HTML in the following    WML was specifically designed for wireless terminals with a target screen that is only a few lines long and about an inch wide. WML is case sensitive , and all tags and attributes should be in lowercase. WML doesn't assume that a keyboard or a mouse is available for user input
    7. 7. WAP Components (contd)…  WAP Gateway   Encoder: converts WML to binarized WML Adaptor: provides additional information through HTTP header    Translate HTTP requests to WSP. Convert between SSL and WTLS Convert transport protocols (TCP and WDP
    8. 8. WML Script  WML uses WML Script to run simple code on the client. WML Script is a light JavaScript language. However, WML scripts are not embedded in the WML pages. WML pages only contains references to script URLs. WML scripts need to be compiled into byte code on a server before they can run in a WAP browser.
    9. 9. WAP Homepages   WAP homepages are not very different from HTML homepages. The markup language used for WAP is WML (Wireless Markup Language). WML uses tags - just like HTML - but the syntax is stricter and conforms to the XML 1.0 standard. WML pages have the extension *.WML, just like HTML pages have the extension *.HTML.
    10. 10. WML Tags   WML is mostly about text. Tags that would slow down the communication with handheld devices are not a part of the WML standard. The use of tables and images is strongly restricted.  Since WML is an XML application, all tags are case sensitive (<wml> is not the same as <WML>), and all tags must be properly closed.
    11. 11. Example of WML … . Navigation Variables Input Elements <WML> <CARD> <DO TYPE=“ACCEPT”> <GO URL=“#eCard”/> </DO Welcome! </CARD> <CARD NAME=“eCard”> <DO TYPE=“ACCEPT”> <GO URL=“/submit?N=$(N)&S=$(S)”/> </DO> Enter name: <INPUT KEY=“N”/> Choose speed: <SELECT KEY=“S”> <OPTION VALUE=“0”>Fast</OPTION> <OPTION VALUE=“1”>Slow</OPTION> <SELECT> </CARD> </WML> Card
    12. 12. WML Decks and Cards WML pages are called DECKS. They are constructed as a set of CARDS, related to each other with links. When a WML page is accessed from a mobile phone, all the cards in the page are downloaded from the WAP server. Navigation between the cards is done by the phone computer inside the phone - without any extra access trips to the server.
    13. 13. Limitations of Internet for Wireless Applications  Traditional Internet applications cannot run on mobile devices because of the following limitations:        Low bandwidth network High Latency network Limited connection stability Small display size Limited input facility Limited memory Limited processing power
    14. 14. WAP brings Internet to Handheld Devices  WAP handles limited bandwidth     Minimizes traffic over wireless interface WSP layer, too, is binary encoded WTP is not only designed to minimize amount of data but also number of transactions WAP handles high latency   WAE uses scripting to avoid round trip delays, e.g. by validating user input locally WTAI environment introduces a repository to hold services that should be started in response to an event in mobile network, e.g. incoming call.
    15. 15. WAP brings (contd)…  WAP handles less stable connections     The sessions supported by WSP are assumed to be long-lived. WTP layer has been kept very simple compared to TCP WTP supports selective retransmission of data WAP handles small displays   WML structures its documents in ‘Decks & Cards’ When an application is executed, user navigates through a series of cards
    16. 16. WAP brings (contd)…  WAP handles limited input facilities     The WML elements can be easily be implemented without much input required from the key-board Deck & Cards model requires minimal navigation between pages Soft buttons or user-definable keys are also supported by WML WAP handles limited memory and CPU    Defining a light weight protocol stack Limited functionality provided by WML & WMLScript Binary encoding of WML & WMLScript
    17. 17. Some WAP applications  Location-based services      Real-time traffic reporting Event/restaurant recommendation Highly customized ads Instant messaging-type “buddy” location Enterprise solutions     Email access Database access A “global intranet” Information updates “pushed” to WAP devices Financial services – – – – Banking Bill-paying Stock trading Funds transfers Travel services – Schedules and rescheduling – Reservations