On the system and structure of WAP

System

　　The system and structure of WAP

WAP is an unauthorized, platform-independent protocol for intelligent information transmission to wireless terminals. WAP Forum was founded in early 1998, is a Nokia, Ericsson, Motorola, Unwired Planet, such as the launch of four companies, now has more than 100 companies and institutions of the industry associations, It is committed to developing a de facto global standard for wireless information and telephony services for digital mobile phones and other wireless terminal devices. The goal of the forum is to combine the wireless industry value chain companies together to ensure product interoperability and wireless market development.

WAP is designed for small screens, low connection speeds, and the need for small memory devices to go online. Through WAP, people can use mobile phone or pager to do online audit, deposit, transfer, or through mobile phone to browse some service information, such as hotels, weather, traffic information. In E-commerce, enterprise network, information services and other aspects, WAP will be a promising prospect. It is predicted that 100 million WAP-compatible devices will be available worldwide by the end of 2000, and up to 525 million WAP devices will be delivered to the United States and Western Europe by 2003.

WAP provides a medium for connecting services, information, and other users in a secure, fast, flexible, online, and interactive manner. A convenient and secure access to related internet/intranet information from a mobile phone, pager, or other wireless device is available to the user. You can also get message notification and call management, e-mail, value-added service and joint messaging, map and location services, weather and traffic forecasts, news, sports information Services, E-COMMERCE transactions and banking services, online address Book and directory services, and enterprise intranet applications, and many other services.

Wireless Application Protocol (WAP) can be built in GSM-900,GSM-1800,GSM-1900,CDMA is-95,tdma,is-136 (ie damps), third generation system--IMT-2000,UMTS,W-CDMA, broadband IS-95, Flex paging System, CDPD and other systems.

　　Model of 1.WAP:

The WAP programming model is similar to the WWW program model, and the Protocol makers can take advantage of the familiar programming model, reliable system and existing tools, as far as possible, and as the starting point of WAP technology. For the characteristics of wireless environment, WAP technology has been optimized, and several extensions have been added. WAP content and application vendors use content formats based on the WWW content format, content delivery also uses a series of communication protocols based on the WWW protocol, and the micro-browsers that manage the user interface are similar to the standard Web browsers. WAP defines the criteria for allowing communication between a mobile terminal and a network server, including:

The standard name Model--WWW standard URLs are also used to define WAP content and source servers;

Content Type--wap content has a specific type that is consistent with the WWW type

Standard content format--wap content formats are based on WWW technology, including display logos, calendars, graphics, and scripting languages.

Standard communication Protocol--request transfer between a mobile terminal and a network server

WAP content categories and protocols have been optimized for most handheld devices. The WAP specification uses standard Web Proxy technology to connect the wireless network to the Web, WAP greatly reduces the operating load on the handset and provides the basis for the low cost of the handset. For example, a WAP gateway can generally use all DNS services to resolve domain names used in URLs, so it no longer requires a mobile phone to perform this computing task. In addition, the network can also use WAP network Guan Lai to provide users with a variety of services, and can help network service providers to prevent fraud and service utilization. WAP Proxy connects wireless domain and WWW, mainly has the following functions:

* Protocol Gateway.

The Protocol gateway translates requests from the WAP protocol stack into the WWW Protocol (HTTP and TCP/IP).

Content encoders and decoders. The content encoder translates Web content into a compressed-coded format to reduce the size and number of packets transmitted over the wireless data network.

This structure enables mobile end users to browse various WAP content and applications, regardless of the type of wireless network they are using. Application developers are able to create network and terminal independent content services and applications that enable them to be used and accessed by as many users as possible. With WAP proxies, content and applications can be placed on a standard WWW server, and developers can continue to use common web technologies such as CGI programming for development.

WAP gateways can also aggregate data from different Web servers and buffer frequently used information, reducing the answer time for handheld devices.

A WAP gateway can also dynamically customize a WML page for a group of users, using information from the wireless network, such as location information, with the user's database interface.

　　2.WAP Architecture

The Cascade-arranged WAP protocol system provides a scalable and extensible environment for the application development of wireless devices. Each layer of protocol or other service and application can directly talk to its next layer of protocol. With a well-defined set of interfaces, perimeter services and applications can utilize a variety of functions provided by the WAP system, including direct use of Session layer, transaction layer, security layer, transport layer, etc.

The following protocols are included in the WAP protocol stack:

WAP Wireless Application Protocol

Wae Wireless Application Environment

WML Wireless Markup Language

WTA Wireless Telephony Application

Wtai Wireless Telephony Application Interface

WSP Wireless Session Protocol

WTP Wireless Transaction Protocol

WTLS Wireless Transport Layer Security

WDP Wireless Datagram Protocol

URL Universal Resource Locator

Sim ATK SIM Application Toolkit

2.1 Wireless Application Environment (WAE) wireless Application Environment:

Wae is an application environment based on the combination of mobile technology and WWW, with the aim of establishing an interactive operating environment for operators, service providers and applications, so that they can access different platforms flexibly. Wae contains a miniature browser with the following features:

Wireless Markup Language WML: A lightweight markup language, similar to HTML, designed to be optimized for handheld terminals;

WMLScript: Lightweight scripting language, similar to JavaScript

Wireless Telephone Application: Telephony service and its programming interface;

Content format: A well-designed data format that includes images, phone books, and calendar information.

2.2 Wireless Session Protocol (WSP) Wireless Conversation protocol

WSP provides a unified interface for two session services to the WAP application layer, one for connection-oriented services over the Transport Layer protocol WTP, and the other for connectionless services on secure or unsecured datagram Services (WDP). The WSP series protocol is optimized for low power, long latency network data carriers, which are now comprised of browsing applications (wsp/browsing), wsp/b allow WAP proxy connections to wsp/b clients and standard HTTP servers, with the following features:

* http/1.1 functions and syntax in wireless coding

* Longer Session state

* The session pauses or continues as the speaker moves

* Establish a common device for transmitting reliable or unreliable data

* Negotiation of the Agreement

2.3 Wireless Transaction Protocol (WTP) Wireless Processing protocol

WTP runs on top of the data services and provides a lightweight protocol for transmission-oriented applications for "lightweight" customers (mobile terminals). WTP can be effectively run on a secure or unsecured wireless data network with the following features:

1. Three-level transmission services:

* Unreliable one-way request

* A reliable one-way request

* Reliable two-way request-answer transmission

2. Selectable user-user connection, WTP the user to confirm each received message

3. Selectable Out-of-band Data validation

4. PDU connection and delay confirmation to reduce the number of messages transmitted

5. Asynchronous transmission

2.4 Wireless Transport Layer Security (WTLS) wireless Transport Layer safety

WTLS is a security protocol based on industrial Standard-TLS (formerly known as SSL), which is also optimized for narrow-band channels used in mobile communications and should be used concurrently with WAP transport protocols. The application may choose to enable or not enable the WTLS feature, depending on its security requirements and network characteristics. The functions of WTLS are as follows:

L Data integrity: The WTLS has the consistency of the data transmitted between the terminal and the server and does not damage;

L Transmission Confidentiality: WTLS guarantees end-to-end data confidentiality and can be read by the intermediary of the data transfer process

L Authentication: terminal to server checksum

L Denial of Service protection: verifies and rejects duplicate and improperly identifiable data to protect upper layer protocols in addition, WTLS can also be used for secure communication between terminals and terminals, such as the authentication of exchange electronic trading cards.

2.5 Wireless Datagram Protocol (WDP) WDP is the Transport Layer protocol of WAP system

WDP can be run on a variety of network data carriers. As a universal transmission protocol, it will transform the transmission port according to the underlying data carrier, thus providing a unified interface for the upper layer protocol in the WAP system, so that the session layer and the application layer are independent of the underlying wireless network. If you can maintain the consistency of the interface and basic functions of the transport layer, a wide range of interactive operations can be realized through the mediation gateway.

2.6 Bearer (Data carrier):

The WAP protocol is designed to enable it to operate independently of various data carriers, such as SMS (short message, CSD, packet data, etc.). Because the data carrier has different quality because of the load capacity, the fault tolerance rate and the delay, the WAP protocol needs to compensate or tolerate these characteristics. The communication of other hierarchical protocols and data vectors in the WDP centralized processing system, in addition to the data types that are now supported, will evolve to support more data types as new data services appear in the mobile market.

2.7 Other services and applications:

The WAP protocol also enables other services and applications to use WAP-provided functionality through a set of well-designed interfaces. The perimeter application can be directly cut into the session layer, the transaction layer, the security layer and the transport layer, although such valuable applications are not defined in the WAP standard. WAP protocol can be used to develop such as email, calendar, phone number, handwriting board, E-commerce and Yellow Pages, white pages and other services.

2.8 WIRELESS TELEPHONY Application (WTA)

The WAP standard also defines a protocol named WTA.

It is a communications-oriented technology that enables WAP to fuse advanced services in telecommunications networks, such as intelligent networks (intelligent Networks). In the fusion of browser-based WAP user interface, WTA can directly enjoy the service based on the intelligent network without modifying the terminal.

The status of 3.WAP and future WAP forums were released in April 1998 by WAP v1.0,v1.1 by May 1999. WAP v1.1 has the same functionality as WAP v1.0 and adds detailed feedback from the first users in a new version prepared for business applications. WAP uses a number of Internet standards, such as XML, UDP, and IP. Many of the reserved protocols are based on Internet standards such as HTTP and TLS, but are optimized to accommodate the special limitations of the wireless environment. Future WAP will include End-to-end security, smart card interface, connection-oriented transport protocol, continuous storage, billing interface and push technology, and will be developed to support multimedia mobile services.