Transmission Control Protocol and Internet Protocol work together on the Internet. Internet Protocol (IP) is responsible for transmitting messages from one host to another. For security reasons, messages are divided into small packets during transmission.
Transmission Control Protocol (TCP) is responsible for collecting these packets, arranging them in an appropriate order and sending them out, and then restoring them correctly after receiving them at the receiving end. The transmission protocol ensures that the data packet is accurate in transmission.
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WAP is the abbreviation of "Wireless Application Protocol" in English, which means "Wireless Application Protocol". It consists of a series of protocols that regulate wireless communication devices such as mobile phones and mobile terminals. It is responsible for connecting the Internet and the mobile communication network, and has objectively become the standard for mobile terminals to access the Internet. WAP closely links the mobile network with the Internet and Intranet, and provides a mobile value-added service that has nothing to do with network types, operators and terminal equipment. Mobile users can access the Internet with their own pocket-sized mobile devices (such as WAP mobile phones, which support WAP protocol) just like using desktop computers to access information, so as to browse the contents on the Internet anytime and anywhere on the screen of mobile phones, such as sending and receiving emails, querying data, browsing financial information, financial information and so on.
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Characteristics of WAP
The emergence of wireless application protocol is to enable mobile devices to directly access resources on the Internet. At present, WAP has become a hot spot in the mobile communication industry. It has the following characteristics:
WAP is an open global wireless fidelity standard, which is based on the existing Internet standards.
Today's society is in the era of knowledge economy, and the economic operation is developing in the direction of real-time, mobility and informatization, which in turn promotes the demand for wireless data. At present, the mobility of the population is greater than ever before, and many people need to go online when traveling. Therefore, mobile phones have become a wise choice to meet this demand. However, due to the lack of open public standards for accessing the Internet through mobile phones and other wireless devices, the market possibility of wireless data is still relatively small. With the emergence of open wireless application protocol WAP, this situation is changing.
Because the wireless environment is very different from the wired information technology (IT) environment, WAP specification is based on the current Internet standard and several new Internet-based protocols, and is optimized according to the uniqueness of the wireless environment, and the constraints of the wireless network (weak CPU, small storage capacity, limited power consumption, small display screen and different input devices) are also considered. WAP uses a programming model and a programming language to develop applications, which reduces the risk of market segmentation and is obviously beneficial to end users, operators, application developers and telecommunications. Therefore, WAP has become a global standard.
In many cases, the key part of WAP is based on the Internet. So it is very simple to compare these two parts with each other. The application layer includes Wireless Markup Language (WML), WMLScript and Wireless Phone Application (WTA). WML (a browsing language similar to HTML) provides browsing support, data input, hyperlinks, text and image display, and tables. WMLScript is equivalent to JavaScript, which enables mobile devices to process information before sending it to the server. WTA allows telephone functions, such as call control.
WAP-compliant phones are equipped with a micro browser, which is comparable to the standard web browser. Users can browse the Web service designated by the operator through the micro browser. The end user first selects a service, which starts to download the card set to the mobile phone; Then, users can browse back and forth between cards, make choices and input information; Then perform the selected work. Browsed information can be cached for later use. Cards can be bookmarked for quick retrieval. The micro browser can also support electronic business cards, calendar events and other types of content formats. Other layers include wireless session layer (based on Hypertext Transfer Protocol HTTP) and wireless transaction protocol layer (based on TCP/IP). Regarding security, the Wireless Transport Layer (WTLS) will provide data integrity, confidentiality, authentication and denial of service protection.
WAP provides an open and unified technical platform.
It uses a Web server to provide Internet or intranet content services. Therefore, the existing balance of technicians with various development experiences is maintained. For example: CGI, ASP, NSAPI, ISAPI, Java and Servlets.
WAP defines an XML (Extensible Markup Language) syntax called WML (Wireless Markup Language).
All WML content on the Internet is operated using standard HTTP requests. In other words, the mobile phone supporting WAP protocol can not directly interpret the HTML pages on the Internet, but can interpret the page information filtered and translated by a specific server.
WAP protocol can be widely used in GSM, CDMA, TDMA, 3G and other networks.
In other words, it does not depend on some kind of network. Today's WAP service may still exist after the arrival of 3G, but the transmission rate will be faster and the protocol standard will be upgraded. WAP is designed as an independent operator, and can use various devices to obtain the best transmission choice. Therefore, it can be used in various communication networks, including short message service (SMS), 9.6kbit/s GSM data, unstructured supplementary service data (USSD), high-speed circuit-switched data (HSCSD), TDMA, CDMA, wideband CDMA and General Packet Radio Service (GPRS). End users can connect to the Internet without knowing advanced wireless network technology.
In order to maintain the existing huge mobile market, WML user interface is directly mapped to the existing mobile phone interface.
This means that end users can use WAP-enabled mobile phones and devices without producing new WAP-specific wireless devices. WAP protocol enables products to continue to use standard Internet technology to optimize existing products. Wireless fidelity will be suitable for the characteristics of existing and future wireless network devices.
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A brief history of WAP
Before the advent of the Internet era, in the early 1990s, major manufacturers of handheld wireless phones clearly realized that wireless networks and the Internet might eventually merge, and began to devote themselves to technical research. Meanwhile, wireless planet? The company (now renamed Phone.com) also started the research work of this fusion technology.
Wireless Markup Language (WML) is based on HDML (Handheld Device Markup Language) of Phone.com Company. Phone.com Company is currently recognized as a provider of WAP compatible micro-browser and WAP gateway technology.
1In June, 1997, Phone.com established WAP Forum in cooperation with Ericsson, Motorola and Nokia, which are the three largest manufacturers of handheld wireless phones in the world. This is a non-profit organization that provides Internet access standards for consumers' wireless devices. WAP Forum is open to all interested parties, especially content developers, equipment manufacturers, operators and infrastructure providers. Its purpose is to establish an applicable, Internet-based global standard that serves the huge wireless market. The four sponsors released the framework of the standard in September, 1997.
The main task of WAP forum is to manage the establishment process of WAP protocol. At the same time, the WAP forum also widely invites other wireless industry partners to join the WAP protocol.
The earliest draft of WAP forum was released in March 1998. It released WAP 1.0. Soon, WAP 1. 1 was released on June 30th, 1999. By September of 1999, WAP 1.2 began the draft. The current version of WAP standard and other technical documents can be downloaded directly from WAP Forum (www.wapforum.com).
By July 2000, the partners of WAP Forum had exceeded 500 companies, including wireless network equipment providers, handset manufacturers, software developers and many other industries, and its members represented 95% of the global mobile phone market. It is precisely because the members of WAP Forum are widely representative, and the WAP specification formulated by WAP Forum has the characteristics that multi-vendor devices can interoperate, so WAP is expected to become a widely accepted and used wireless information network connection mode in the industry.
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Advantages of WAP
With the development of WAP technology, WAP mobile phone is not only a mobile phone, but also a WAP browser and digital data fax machine, which enables users to grasp the communication advantages more comprehensively. As long as users have a WAP mobile phone, they can master everything at any time, and its advantages are manifested in work, life, entertainment and other aspects.
In terms of work, WAP can provide users with the latest first-hand information in the market, and fully meet users' business and work needs. With the help of WAP, merchants have a new channel of contact with consumers, which is especially helpful to open up the huge mobile phone user market. Through WAP technology, users can buy and sell e-commerce online, which will bring more considerable benefits to businesses. At the same time, no matter where users are, they can browse WAP pages like surfing the Internet with a PC, get the weather forecasts of major cities around the world, inquire about the latest stock prices of different stock markets and buy and sell them, and use the global positioning system to accurately search the direction and location of maps in WAP phones ... All these make users break through the barriers of time and space and control freely.
In life, no matter where users are, they can surf the Internet through WAP mobile phones, conduct various online banking services, and even book hotels, buy or book tickets for movies and music parties. Fully meet the actual needs of users' lives and really feel relaxed.
In entertainment, WAP also provides users with a brand-new consumption model. Wherever you go, you can surf the Internet, play games and share the fun of WAP with friends and even other WAP users.
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Limitations of WAP
Although WAP has such strong advantages, it must also point out the technical limitations of WAP, so as to pay attention to it in development and use, solve the bottleneck problem and promote technological development.
The limitations of WAP mainly exist in two aspects: WAP equipment and WAP bearer network.
WAP devices are limited by CPU, random access memory (RAM), read-only memory (ROM) and processing speed. Because WAP devices are mobile wireless devices, the battery life is limited. The greater the bandwidth used, the greater the power required; The greater the required power, the shorter the battery life. In addition, WAP devices have small screens and limited data input capabilities. This is the negative impact of minimizing manufacturing costs.
WAP bearer network is a low-power network with moderate bandwidth, less than10 kbit/s ... The inherent characteristics of WAP bearer network are low reliability, low stability and unpredictability. However, WAP protocol and applications running on WAP devices need robustness and reliability. They must be able to handle service interruptions, intermittent connections and service losses. WAP bearer network has the characteristics of high delay, that is, there will be a perceptible pause in the process from the user requesting an action to the response.
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Development prospect of WAP
WAP has created a business opportunity, enabling users to access previous or new Internet services anytime and anywhere. Users can benefit from the convenience of accessing and using more value-added services provided by any wireless device, and telephone-oriented services can be more easily understood and used.
WAP is an open wireless information processing platform and tool, which enables the communication industry to avoid cost overlap and repeated investment. WAP is an important step in developing wireless data/information processing services, which will improve the universality of wireless data. Developers will be able to write an application development that runs on all carrier networks, all transport protocols and all wireless devices, and access the entire mobile user community in a unified way. Application development can make full use of the end-user interface, because the WAP browser in each wireless device will be able to control the best way to display content on the device. And developers don't have to worry about it, because WAP is an open standard and can transition to the future. In addition, WAP has nothing to do with transmission network technology, so it enables mobile manufacturers to manufacture WAP-compatible mobile terminals and participate in market competition.
WAP can be combined with e-commerce to realize mobile commerce. For example: mobile banking, mobile stock trading, mobile futures trading, mobile phone speculation in foreign exchange and so on. Users are no longer limited by time and place, and can respond to market changes conveniently and quickly. In addition, the customized SIM card can make a special WAP service menu for special users, and users no longer need a complicated dialing process, but directly access value-added services through the quick SIM card menu. And this service customization can also be done wirelessly. Therefore, WAP will help to increase revenue, win new customers, reduce confusion and reduce costs.
At present, although WAP still has some problems, such as security, smart card interface, connection-oriented transmission protocol, persistent storage, billing interface and so on. WAP Forum is working with several standards organizations to optimize HTML and HTTP standards for wireless environment. WAP Forum and its members will continue to help formulate new technical standards compatible with wireless data. The development of mobile communication may include voice, image, video and many data at the same time. In the development of wireless data, such as WAP, it will help guide people to enter the personal multimedia world and develop into the next generation multimedia.