Wireless Application Protocol (WAP)
Herinta Yogi Rostana, ST
KEMENTERIAN PENDIDIKAN NASIONAL DIREKTORAT JENDERAL PENINGKATAN MUTU PENDIDIK DAN TENAGA KEPENDIDIKAN
PUSAT PENGEMBANGAN DAN PEMBERDAYAAN PENDIDIK DAN TENAGA KEPENDIDIKAN MATEMATIKA
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What is the Wireless Application Protocol (WAP)? The delivery of interactive and real-time information services over a mobile network to conforming hand-held digital devices. Examples of such devices are PDAs and mobile telephones with displays. WAP aims to integrate Internet, wireless data, and telephony. WAP works with all types of wireless networks including GSM, TDMA, CDMA, and the upcoming 3G networks. WAP is the wireless counterpart of the Internet protocol HTTP and the Web markup language HTML. WAP addresses issues relating to wireless interaction, which is characterized by low bandwidth and devices with small displays, limited processing power and memory, and batteries that can operate only for limited periods without being recharged. Although WAP follows the client-server Web model of interaction, WAP is incompatible with HTTP and HTML. Consequently, WAP gateways (proxies) are needed to sit between the client (WAP device) and the Web servers. Incidentally, the newer version of WAP, WAP 2.0, supports HTTP, but a gateway is still required for reasons such as WML compression, dynamic conversion of HTML to WML, etc. WAP gateways intercept and handle user requests to Web servers and process the responses. A Web server may generate WML content for WAP devices or it may simply dish out HTML (or XML). In case the Web server generates HTML (XML), the WAP gateways must convert the HTML (XML) to WML. Before sending the WML to the WAP device, the gateway compresses it to WMLC (the C in WMLC is for compressed). If the WML generated by the Web sever is already WMLC,
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then the compression step is skipped and the server response passed on to the WAP device.
What are the Advantages of WAP? Using WAP, which is a global and open standard, has the following advantages: * Portability: A WAP application on one network should be easily portable to a different environment with little or no change. The alternative to using WAP is to write applications using proprietary protocols. Such applications will require substantial code rewriting when porting to a − different type of network (examples of network types are GSM and CDMA), − different bearer protocol (examples of bearer protocols are SMS, short message service or CSD, circuit switched data), or − a new device type. * User Experience: WAP aims to enhance the user experience by addressing characteristics of wireless environment: − Narrow bandwidth connection. − Devices with small screens, limited battery use without recharging, limited memory, and limited processing power.
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Cost and Application Development Time Reduction: New services can be added quickly and at a lower cost using WAP. This is made possible by the easy availability of standardized WAP tools and platforms such as WAP software development tool kits, WAP gateways, and WAP devices.
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Operators For wireless network operators, WAP promises to decrease Churn, cut costs, and increase the subscribers base both by Improving existing services, such as interfaces to voice-mail and Prepaid systems, and facilitating an unlimited range of new value-added services and applications, such as account management and billing inquiries. New applications can be introduced quickly and easily without the need for additional infrastructure or modifications to the phone. This will allow operators to differentiate themselves from their competitors with new, customized information services. WAP is an interoperable framework, enabling the provision of end-to-end turnkey solutions that will create a lasting competitive advantage, build consumer loyalty, and increase revenues.
The WAP Model The WAP programming model (Figure 2) is similar to the WWW programming model. This provides several benefits to the application developer community, including a familiar programming model, a proven architecture, and the ability to leverage existing tools (eg, Web servers, XML tools, etc.). Optimisations and extensions have been made in order to match the characteristics of the wireless environment. Wherever
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possible, existing standards have been adopted or have been used as the starting point for the WAP technology.
WAP content and applications are specified in a set of well-known content formats based on the familiar WWW content formats. Content is transported using a set of standard communication protocols based on the WWW communication protocols. A micro browser in the wireless terminal co-ordinates the user interface and is analogous to a standard web browser. WAP defines a set of standard components that enable communication between mobile terminals and network servers, including: · Standard naming model – WWW-standard URLs are used to identify WAP content on origin servers. WWW-standard URIs are used to identify local resources in a device, eg call control functions. · Content typing – All WAP content is given a specific type consistent with WWW typing. This allows WAP user agents to correctly process
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the content based on its type. · Standard content formats – WAP content formats are based on WWW technology and include display markup, calendar information, electronic business card objects, images and scripting language. · Standard communication protocols – WAP communication protocols enable the communication of browser requests from the mobile terminal to the network web server.
Example WAP Network The following is for illustrative purposes only.
In the example, the WAP client communicates with two servers in the wireless network. The WAP proxy translates WAP requests to WWW
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requests thereby allowing the WAP client to submit requests to the web server.
The proxy also encodes the responses from the web server into the compact binary format understood by the client.
If the web server provides WAP content (e.g., WML), the WAP proxy retrieves it directly from the web server. However, if the web server provides WWW content (such as HTML), a filter is used to translate the WWW content into WAP content. For example, the HTML filter would translate HTML into WML. The Wireless Telephony Application (WTA) server is an example origin or gateway server that responds to requests from the WAP client directly. The WTA server is used to provide WAP access to features of the wireless network provider’s telecommunications infrastructure.
What are the Components of WAP? The major components of the WAP specification are: * Protocol Support − IP networks: Protocols supported include the wireless“profiled” versions of TCP (called WP-TCP), TLS, and HTTP (called WP-HTTP). ‒ Non-IP networks: Wireless Session Protocol (WSP), Wireless Transaction Protocol (WTP), Wireless Transport Layer Security (WTLS), and Wireless Datagram Protocol (WDP). * Application Environment − WML Specification: WML is a markup language like HTML based on XML and XHTML (the XML version of HTML). WML
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is designed for devices with small screens, limited processing power, and low bandwidth connection to the servers. − WMLScript Specification: WMLScript is a scripting language, similar to JavaScript, for running code on clients. − WAP Micro Browser. The WAP micro browser is designed especially for operating in the limited resource environment of WAP devices. * Services and Capabilities − Real-time Content Delivery: WAP provides facilities for asynchronously “pushing” content to WAP devices allowing the immediate delivery of real-time messages, alerts, and other content that needs to be delivered immediately. − Customization of User Profile: WAP allows servers to customize content delivered to users based on user preferences and client device capabilities. − Telephony Support: WAP enables telephone services to be operated from within a data environment. Consequently, WAP phones can operate as integrated voice and web devices.
Components of the WAP Architecture The WAP architecture provides a scaleable and extensible environment for application development for mobile communication devices. This is achieved through a layered design of the entire protocol stack (Figure 4). Each ofthe layers of the architecture is accessible by the layers above, as well as by other services and applications. Wireless Application Environment (WAE) The Wireless Application Environment (WAE) is a general-purpose application environment based on acombination of World Wide Web
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(WWW) and Mobile Telephony technologies. The primary objective of the WAE effort is to establish an interoperable environment that will allow operators and service providers to build applications and services that can reach a wide variety of different wireless platforms in an efficient and useful manner. WAE includes a micro-browser environment containing the following functionality: · Wireless Markup Language (WML) – a lightweight markup language, similar to HTML, but optimised for use in hand-held mobile terminals; · WMLScript – a lightweight scripting language, similar to JavaScript™; · Wireless Telephony Application (WTA, WTAI) – telephony services and programming interfaces; and · Content Formats – a set of well-defined data formats, including images, phone book records and calendar information. Wireless Session Protocol (WSP) The Wireless Session Protocol (WSP) provides the application layer of WAP with a consistent interface for two session services. The first is a connection-oriented service that operates above the transaction layer protocol WTP. The second is a connectionless service that operates above a secure or non-secure datagram service (WDP). The Wireless Session Protocols currently consist of services suited for browsing applications (WSP/B). WSP/B provides the following functionality: HTTP/1.1 functionality and semantics in a compact over-the-air encoding, Long-lived session state, Session suspend and resume with session migration, A common facility for reliable and unreliable data push, and Protocol feature negotiation.
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The protocols in the WSP family are optimised for low-bandwidth bearer networks with relatively long latency. WSP/B is designed to allow a WAP proxy to connect a WSP/B client to a standard HTTP server. Wireless Transaction Protocol (WTP) The Wireless Transaction Protocol (WTP) runs on top of a datagram service and provides as a light-weight transaction-oriented protocol that is suitable for implementation in “thin” clients (mobile stations). WTP operates efficiently over secure or non-secure wireless datagram networks and provides the following features: · Three classes of transaction service: · Unreliable one-way requests, · Reliable one-way requests, and · Reliable two-way request-reply transactions; · Optional user-to-user reliability - WTP user triggers the confirmation of each received message; · Optional out-of-band data on acknowledgements; · PDU concatenation and delayed acknowledgement to reduce the number of messages sent; and · Asynchronous transactions. Wireless Transport Layer Security (WTLS) WTLS is a security protocol based upon the industry-standard Transport Layer Security (TLS) protocol, formerly known as Secure Sockets Layer (SSL). WTLS is intended for use with the WAP transport protocols and has been optimised for use over narrow-band communication channels. WTLS provides the following features: · Data integrity – WTLS contains facilities to ensure that data sent between the terminal and an application server is unchanged and
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uncorrupted. · Privacy – WTLS contains facilities to ensures that data transmitted between the terminal and an application server is private and cannot be understood by any intermediate parties that may have intercepted the data stream. · Authentication – WTLS contains facilities to establish the authenticity of the terminal and application server. · Denial-of-service protection – WTLS contains facilities for detecting and rejecting data that is replayed or not successfully verified. WTLS makes many typical denial-of-service attacks harder to accomplish and protects the upper protocol layers. WTLS may also be used for secure communication between terminals, eg, for authentication of electronic business card exchange. Applications are able to selectively enable or disable WTLS features depending on their security requirements and the characteristics of the underlying network (eg, privacy may be disabled on networks already providing this service at a lower layer).
Wireless Datagram Protocol (WDP) The Transport layer protocol in the WAP architecture is referred to as the Wireless Datagram Protocol (WDP). The WDP layer operates above the data capable bearer services supported by the various network types. As ageneral transport service, WDP offers a consistent service to the upper layer protocols of WAP and communicate transparently over one of the available bearer services. Since the WDP protocols provide a common interface to the upper layer protocols the Security, Session and Application layers are
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able to function independently of the underlying wireless network. This is accomplished by adapting the transport layer to specific features of the underlying bearer. By keeping the transport layer interface and the basic features consistent, global interoperability can be achieved using mediating gateways.
Exercise : Open website http://mywibes.com - interface homepage mywibes.com
then click on the list of accounts‌..
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then the page will look like this. on this page, you can fill in the fields that are already available.
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after you have successfully done filling in the available field, the page will appear beriku website like this. This page shows some examples of the WAP page design property of others. You can view or retrieve the page for you to use as reference in making your WAP pages.
then on the next activity, you can select the menu maker. makers on the menu, there are various kinds of facilities like building, style, site description, site logo, extra domains, paging makers, IP statistics and backlist. for each facility, can be tried on learning sessions with teachers.
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the next can lead to a content page, this page contains any material that we will use in making your own WAP site.
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The next page is a community page, where on this page you can create a variety of easy to establish communication with others.
This page contains on the subject of advertising
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