Slide 1

Wireless Markup Language - Vedantis Slide 2 Copyright [Vedantis Inc.]. All rights reserved Wireless Markup Language o Introduction Internet today has made its impact felt in every field of life such as banking, research or healthcare. Till recent times people on move were not able to gain access to latest information or other vital services such as e-mail provided by internet. Now WAP (Wireless Application Protocol) facilitates mobile user to access internet through their handsets. WAP is defined as a communication protocol and application environment for deployment of information resources, advanced telephony resources and internet access. o Evolution Of WAP The trends towards smaller and faster devices coupled with need for information access on the move encouraged wireless industry to make efforts to provide internet access to its user. Evolution of WAP can be categorized as follows: Slide 3 Copyright [Vedantis Inc.]. All rights reserved Wireless Markup Language o Evolution Of WAP (.Contd) 1995 : Erricsion : Developed value added services for mobile networks. They developed a protocol, ITTP (Intelligent Terminal Transfer Protocol) to enable communication between a service node, which would provide information and mobile telephone that receives the information. 1996 1997 : Unwired Planet, Nokia : Introduced HDML a cut down version of HTML, designed to run on wireless devices. March 1997 : Nokia : Presented smart messaging concept which had a special internet access service technology for (Global System for Mobile Communication) GSM devices. They also introduced SMS and TTML that is Tagged Text Markup Language to enable communication to Server and handhelds. December 1997 : Nokia, Motorola, Ericsson, Unwired Planet : came together to form common forum called WAP forum to tackle issues with WAP technology. Efforts of this forum resulted in the emergence of the number of standards and their incorporation into the development of 1.0 that combined technology from ITTP, HDML and TTML. Slide 4 Copyright [Vedantis Inc.]. All rights reserved Wireless Markup Language o Advantages: Mobility: It is the ability to access the information and services any time any where. WAP enabled device can make full use of online services anywhere and any time. Interoperability between WAP Compliant devices: WAP is designed to encourage easy and open interoperability between WAP compliant devices. Handset manufacturers are clearly assured that if their device is made WAP compliant it will be able to interface with any WAP server regardless of manufacturer. Network Independence: Allows WAP applications to work across all networks and enables handset manufacturers to use common code across all product lines. Basic principle is that it works with any interface. Applications can now be developed using single standard that will work across variety of networks. WAP led to development of GPRS (General Packet Radio Service) which is a packet switched wireless protocol, is IP based and has higher data transfer speeds. EDGE is enhancement to GPRS, allows transmission speed of 384 KBitsPS. Slide 5 Copyright [Vedantis Inc.]. All rights reserved Wireless Markup Language o Advantages: (Contd) Network Independence: (Contd) 3G provides the next thrust to wireless internet revolution providing maximum speed of 2MBits/sec. Device Independence: WAP forum is promoting WAP specification for wide variety of mobile devices, including PDA. According to the specification, client side application should be easily accessible by all the devices. This ensures system is device independent. Slide 6 Copyright [Vedantis Inc.]. All rights reserved Wireless Markup Language o Introduction to WAP architecture: WAP architecture is based on client server model and closely follows the design of web architecture. Presence of WAP gateway is the only major difference between the WAP and web architectures. WAP specification lists the main system and the protocol architectures of WAP and facilitates the understanding of WAP technologies. Also provides range of framework for range of various protocols, features. WAP ClientGatewayServer Send request Sends Content Convert and Send request Send response Slide 7 Copyright [Vedantis Inc.]. All rights reserved Wireless Markup Language o Components of WAP Architecture: WAP Client. WAP Device. WAP Browser. WAP Gateway. Network operator. Application Server. Slide 8 Copyright [Vedantis Inc.]. All rights reserved Wireless Markup Language o Component of WAP architecture : WAP Client A WAP client is the logical entity that is operated by the user to communicate with the server. It is the entity that accesses content from internet through a WAP gateway. Specification to become WAP compliant: WAE User Agent. WTA User Agent. WAP Stack. WTA User Agent WAE User Agent WAP Stack WAE WSP WTP WTLS WDP Slide 9 Copyright [Vedantis Inc.]. All rights reserved Wireless Markup Language o Component of WAP architecture : WAP Client (Contd) WAE: Wireless Application Environment: Its the micro browser that delivers the content for display. Its the software allowing user to access the internet from a mobile device. It receives WML script, images from WAP Gateway. It also manage interaction with user such as text input or error or warning message. WTA: Wireless Telephony Application: Retrieves WTA functions receives files sent by WTA server and executes them. They store library that contain both local and network WTA functions. Provides interface on phone. Also access to network functionality such as number dialing, message management and location indication services. WAP Stack: Allows the mobile devices to connect to WAP gateway using the WAP protocol, such as WAE. Slide 10 Copyright [Vedantis Inc.]. All rights reserved Wireless Markup Language o Component of WAP architecture : WAP Device Any physical device that is WAP compliant, can be a mobile phone, PDA or handheld computer. o Component of WAP architecture : WAP Browser Its software that runs on WAP device. It reads content that arrives from internet and also displays it on WAP device. Also helps for navigation. The WAP client accesses the content from the internet and uses the WAP browser to display it to user. o Component of WAP architecture : WAP Gateway WAP gateway is situated between the WAP device and the server. It intermediates between the device and the server and enable them to communicate. It forms a bridge between 2 distinct worlds the internet and mobile network which is fundamentally different in their underlying technologies. Its a software that supports WAP and IP network. Comparison between Web and WAP models. Slide 11 Copyright [Vedantis Inc.]. All rights reserved Wireless Markup Language o Component of WAP architecture : WAP Gateway Processing of request in WAP world: WAP Client (WAE User Agent) Gateway (Encoder and Decoder WSP HTTP ) Server (CGI Scripts etc) Encoded Request: in WSP WSP is binary form of HTTP Address is preconfigured in mobile Request is parsed to resolve domain name Of URL to IP address. HTTP or HTTPS request is sent. Server returns static content. HTTP response sent back to Gateway Data is converted and sent to Mobile Slide 12 Copyright [Vedantis Inc.]. All rights reserved Wireless Markup Language o Component of WAP architecture : Network Operator Provides carrier services and usable value added services to subscribers. Network operator also offers more usable interfaces to current services, in addition to entirely new ones. Must support this by being interoperable, scalable, efficient, reliable and secure. Example paying telephone bills. o Component of WAP architecture : Application Server Functions same as that of web server and offers same features to client. The only difference lies in the content that they store and send back to client. Supports files such as HTML, JavaScript, multimedia, and other programming languages. Slide 13 Copyright [Vedantis Inc.]. All rights reserved Wireless Markup Language o WAP Protocol Stack: Introduction A protocol defines the type and the structure of messages that 2 devices use when they communicate over a network. Protocol stack is the set of layers that compose the set of protocols. o WAP Protocol Stack: Layers Application Layer: Wireless Application Environment (WAE) Session Layer: Wireless Session Protocol (WSP) Transaction Layer: Wireless Transaction Protocol (WTP) Security Layer: Wireless Transport Layer Security (WTLS) Transport Layer: Wireless Datagram Protocol (WDP) Bearers (SMS, CSD, USSD, DECT, CDMA) Slide 14 Copyright [Vedantis Inc.]. All rights reserved Wireless Markup Language o WAP Protocol Stack: Layers : Application Layer. Offers an application environment that forms the base for the creation and execution of WAP applications and services. WAE, which forms the application layer is the combination of www and Mobile Telephone technologies. The objective of the WAE is to establish the interoperable environment. o WAP Protocol Stack: Layers : Session Layer. Forms interface between application layer and transaction layer and delivers the functions that are essential for wireless connections. The session layer consists of the protocol WSP, enabling the exchange of information. It consists of 2 different services. Connection-oriented Session service: Operates above transaction layer protocol, WTP Connectionless Session service: Operates directly above transport layer, WDP. Binary transmission of the data between server and client is the essential adaptation that has bee done to tackle narrow bandwidth Slide 15 Copyright [Vedantis Inc.]. All rights reserved Wireless Markup Language o WAP Protocol Stack: Layers : Transaction Layer. It consists of WTP. WTP provides services to accomplish reliable and non- reliable transactions. It operates over transport layer or over the optional security layer. WTP supports binding of protocol data in chain and the delaying response to reduce the number of transmissions. This layer supplies 3 different classes: Unreliable requests Reliable requests Reliable requests with one result message. Unreliable Request: The application server, which is the initiator sends the request to the user agent which is the responder. User agent doesnt acknowledge the request. This transaction has no state and ends when invoked message is sent. Reliable Request: User agent acknowledges the request sent. However the user agent stores the acknowledgement for sometime, so that it can retransmit message to the server, if the server requests it again. Slide 16 Copyright [Vedantis Inc.]. All rights reserved Wireless Markup Language o WAP Protocol Stack: Layers : Transaction Layer.(Contd) Reliable request with one result message: User agent unconditionally acknowledges the request sent by the application server, replying with the result message. The application server acknowledges the result message and sends back the acknowledgement for the result message back to user agent. o WAP Protocol Stack: Layers : Security Layer. Consists of Wireless Transport Layer Security which is provided by the WAP forum as the solution to the security aspect of the wireless technology. WTLS is based upon industry based TLS protocol formerly known as SSL. An adaptation to internet, it attempts to lighten the overheads associated with establishing a secure connection between the two applications. Services provided by WTLS are: Data Integrity: Ensures uncorrupted data transfer to client. Privacy: Contains facilities to ensure data transmission between client and application server is secured and third party cannot understand the intercepted data. Slide 17 Copyright [Vedantis Inc.]. All rights reserved Wireless Markup Language o WAP Protocol Stack: Layers : Security Layer. (Contd) Client Authentication: Contains facilities to authenticate client. Server Authentication: Contains facilities to authenticate server. Applications can selectively enable or disable WTLS depending on their security requirements and characteristics of underlying networks. o WAP Protocol Stack: Layers : Transport Layer. Consist of WDP. WDP is bottom layer of stack and is one of the elements that makes WAP operable on extremely different mobile networks. WAP layer operates above the data capable services supported by various network types. WDP offers consistent service to the upper layer and communicates transparently over one of available services. Provides common interface to upper layer protocols, security, session and applications layers are able to function independently of underlying wireless network. Slide 18 Copyright [Vedantis Inc.]. All rights reserved Wireless Markup Language o WAP Protocol Stack: Layers : Bearers Integrates service and rest of WAP Stack. WDP specification lists the network that are supported and techniques used to allow WAP protocol to run over each network. They include SMS Send short messages. USSD Unstructured Services Service Data combine with GSM standard to form support transmitting information over GSM network DECT Digital Enhanced Cordless Telecommunications a digital radio access standard for wireless communications CDMA Code Division Multiple Access Supports voice and data requirements and provide fast access to mobile devices. Slide 19 Copyright [Vedantis Inc.]. All rights reserved Wireless Markup Language o Components of WAE: Introduction WAE includes all the elements essential for the creation and execution of applications. WAE specifies the formats of images and the text that user agents have to be compliant with. 2 different user agents that are located on client side are: WAE user agent. WTA user agent. o Components of WAE: Components The main components are: WML WMLScript WTA WML: WML is tag based, shares element of HTML, and is defined as an XML document type. Each WML is a single deck that is made up of one or more cards. A card is a unit of interaction on mobile device and is equivalent to HTML page. A set of cards constitutes to a deck. Slide 20 Copyright [Vedantis Inc.]. All rights reserved o Components of WAE: Components WML (Contd) When a user accesses the WAP site the whole deck is first loaded into the memory and the first card is shown to user. WML has very limited capabilities Wireless Markup Language FeaturesDescription Support textCan use emphasize element such as bold, Italics, line, breaks Support ImagesDisplay Wireless bitmap images Accept User InputSubmit text entries, choose list options.. Support VariablesCan include variables in WML code to keep track of information. Navigation and History stack Can include common navigation and history functionality. International character set 16 bits to represent each character. Optimize Narrow Bandwidth Adapts to high latency and narrow band characteristics of wireless networks. Slide 21 Copyright [Vedantis Inc.]. All rights reserved Wireless Markup Language o Components of WAE: Components WMLScript WMLScript is a scripting language. It is based on standardized version of JavaScript called ECMAScript. Also provides a set of libraries for client side mathematical operations and string manipulations, reducing server side validations. Capability of checking and validating the input submitted by user. Methods of interacting to client without taking help of server. Access to device facilities, such as phonebook, calendar, messages. Unlike HTML where scripts are embedded, WML scripts files are separate from WML decks from where they are called. WML Scripts are sent to clients only if they try to access the functionality contained in one of them. Slide 22 Copyright [Vedantis Inc.]. All rights reserved Wireless Markup Language o Components of WAE: Components WTA : Wireless Telephone Applications WTA is extension of WAE that provides set of interface to telephone functionality of mobile device. It can interact with telephony related functions in mobile phones and those provided with mobile phone networks. Some telephony related functions available on mobiles are: Making mobile originated call. Receiving mobile terminated call. Send and receive short text messages. Adding, searching, removing phonebook services. Examining call logs. Pressing key on keypads. Telephony functions available on mobile phone network are: Call holding Call transfer Conferencing and voice mailing. Slide 23 Copyright [Vedantis Inc.]. All rights reserved Wireless Markup Language o WAP Resources: To create WAP application you need to use WML and WML Script. SDKs provide the platform to write code for application. 3 primary tools are: Editor: Interface for writing the code. Complier or Interpreter: Programs that translate code into executable file. Linker: Establishes link between different programs.