Introduction to WAP
- 1. Introduction To By Nitin s
- 2. WAP Network S tructure. WAP Network Protocol Structure WAP Gateway WAP Server WAP Protocol Layer WAP and INTERNET Protocol WAP Layer Information : WAE , WSP, WTP, WTLS, WDP Topic :
- 4. Network Protocol Structure The user presses a phone key that has an URL request assigned to it. The user agent sends an URL request to a WAP gateway using the WAP protocol. 3 The WAP gateway create an conventional HTTP request for the specified URL and sends it to the webserver. 4 The HTTP request is processed by the web server. The URL may refer to a static file or to a CGI or other script application. In the first case, the web server fetches the file and adds an HTTP header to it. If the URL specifies a script application, the web server runs the application. 5 The web server returns the WML deck with the added HTTP header or the WML output from the CGI or other script application. 6 The WAP gateway verifies the HTTP header and the WML content and encodes them to binary form. The gateway then creates a WAP response containing the WML and sends it to the user agent. 7 The user agent receives WAP response. It processes the WML response and displays the first card of the WML deck to the user.
- 5. 1 The user presses a phone key that has an URL request assigned to it. 2 The user agent sends an URL request to WAP gateway using the Wap protocol. 3 The WAP gateway create an conventional HTTP request for the specified URL and sends it to the web server. 4 The HTTP request is processed by the web server. The URL may refer to a static ,CGI or a script application, the web server runs the application or static page. 5 The web server returns the WML deck with the added HTTP header or the WML output from the CGI or other script application. 6 The WAP gateway verifies the HTTP header and the WML content and encodes them to binary form. Then creates a WAP response containing the WML. 7 The user agent receives the WAP response. It processes and displays the first card of the WML deck to the user. WAP Operates as Follows ::
- 6. WAP gateway is a piece of software that has several functions in the "chain" between the WAP device and the web server. Converting the markup language (WML) from textual format to tokenized (binary/compressed) format which is readable by the WAP device. Translating the requests from the WAP device to HTTP requests for the "web" world. Convert between the SSL encryption used in the "web" world and the WTLS encryption used in the WAP world. Convert between the "transport" protocol of the "web", TCP, and that of the WAP world, WDP. WAP Gateway
- 7. WAP Application Server A WAP Server is nothing more than a normal web server and a WAP gateway -like device built into one. The web server supports files such as HTML, JavaScript, multimedia and all types of images. The WAP application server stores WML, WMLScript and WBMP (Wireless Bitmap) images. WAP server usually just a WAP application server with gateway functionality added. It will provide the entire services normal origin server provides, but it will also act as a WAP gateway.
- 8. WAP Protocol has Five Layers: Application Layer(WAE) Session Layer (WSP) Transaction Layer (WTP) Security Layer (WTLS) Datagram Layer (WDP)
- 9. WAP and Internet Protocol stacks WAE provides an application environment intended for the development and execution of portable application and services. WSP supplies method for the organized exchange of content between client/server application. WTP provides different methods for performing transaction, to a varying degree of reliability. This is an optional layer that provides, when present, authentication, privacy and secure connection between application. This is the bottom layer of WAP stack, which shelters the upper layers from the bearer service offered by the operator These are the different ways that a mobile phone can communicate with the wireless network.
- 10. 1 Wireless Datagram Protocol (WDP) The WDP layer operates above the data capable bearer services supported by the various network types. Architecture :: The Adaptation layer: The layer that maps the protocol functions directly onto a specific bearer. The Adaptation Layer is different for each bearer and deals with the specific capabilities and characteristics Services : Application addressing by port numbers,optional segmentation and reassemble and optional error detection. WDP supports several simultaneous communication instances from a higher layer over a single underlying WDP bearer service.
- 11. 2 Wireless Transport Layer Security (WTLS) WTLS is a security protocol based on the industry standard Transport Layer Security (TLS) protocol. The WTLS layer is modular and it depends on the required security level of the given application, or the characteristics of the underlying network. WTLS is designed to function on connection-oriented and/or datagram transport protocols. Primary goal : Data integrity :: Data sent between the terminal and an application server is unchanged and uncorrupted. Privacy :: Data transmitted between the terminal and an application server is private and cannot be understood by any intermediate parties Authentication :: Establish the authenticity of the terminal and application server. Denial-of-service protection :: Detecting and rejecting data that is replayed or not successfully verified. Useful in services such as bank or business transactions over a mobile.
- 12. 3 Wireless Transaction Protocol (WTP) WTP has been defined as a light weight transaction oriented protocol. Suitable for implementation in "thin" clients (mobile stations) and operates efficiently over wireless datagram networks.by the use of unique transaction identifiers, acknowledgements, duplicate removal and retransmissions. WTP is message oriented and designed for services oriented towards transactions, such as "browsing". The basic unit of interchange is an entire message and not a stream of bytes. WTP allows for asynchronous transactions. The Responder sends back the result as the data becomes available. There are 3 classes of transaction service: Class 0: Unreliable invoke message with no result message Class 1: Reliable invoke message with no result message Class 2: Reliable invoke message with exactly one reliable result message For reliable invoke messages, both success and failure is reported. If an invoke cannot be handled by the Responder, an abort message will be returned to the Initiator instead of the result
- 13. 4 Wireless Session Protocol (WSP) The core of the WSP design is a binary form of HTTP. All the methods defined by HTTP/1.1 are supported. WSP provides typed data transfer for the application layer. The lifecycle of a WSP session is not tied to the underlying transport. A session can be suspended while the session is idle. Nit: 1. Consequently, the requests sent to a server and responses going to a client may include both headers (meta-information) and data. 2. WSP provides an optional mechanism for attaching header information (meta-data) to the acknowledgement of a transaction. This allows the client application to communicate specific info about the completed transaction back to the server. WSP also optionally supports asynchronous requests, so that a client can submit multiple requests to the server simultaneously. WSP provides a means for organized exchange of content between cooperating client/server applications. Establish a reliable session from the client to the server and release that session in an orderly manner. Agree on a common level of protocol functionality using capability negotiation Exchange content between client and server using compact encoding Suspend and resume the session WSP defines 2 protocols: 1. connection-mode session services over a transaction service, 2. non-confirmed, connectionless-mode services over a datagram transport service is most suitable for applications which do not need reliable delivery and confirmation.
- 14. 5 Wireless Application Environment (WAE) 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. The application layer of WAP provides an environment that includes all the elements related to the development and execution of application. The main building blocks of the WAE are the following: A lightweight markup language: WML A lightweight scripting language: WMLScript An interface to local services and advanced telephony service: WTA (not yet implement)