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Wireless internet can either be integrated into your phone or accessed via a wireless card. Check out more internet connection images.
Image credit: Cameron Spencer/Getty ImagesEvery day, you and millions of others rely on the Internet for various activities—connecting with people, tracking the stock market, staying updated on news, checking the weather, making travel arrangements, conducting business, shopping, enjoying entertainment, and learning. Staying connected has become so essential that it’s tough to unplug from your computer or internet connection, fearing you might miss an email, a stock update, or breaking news. As your personal or professional life grows more reliant on electronic communication, you may be considering the next step: a device that lets you access the Internet anytime, anywhere.
This is where wireless internet comes into play. You've likely seen ads or news about cell phones and PDAs that allow you to send and receive emails. This seems like a natural progression, but you may have some questions about using the internet on the go. Will you still be able to browse the web? How quickly can you access the information you need? Perhaps you've heard of Wireless Application Protocol (WAP) and are curious about how it functions. Find out what WAP is, why it's necessary, and which devices use it.
The Cellular Revolution
The rapid growth of digital cell phones in recent years has likely been the most crucial factor in the rise of wireless Internet. The expanding digital cellular network and Personal Communication Services (PCS) have formed a strong base for wireless Internet services. It is estimated that over 50 million cell phones with web capabilities are in use. In 1997, companies like Nokia, Motorola, Erion, and Phone.com joined forces to develop the WAP, recognizing the need for a universal standard to successfully implement wireless Internet. Since then, more than 350 companies have joined the WAP Forum.
Making a website accessible on wireless devices presents a considerable challenge. Currently, only a small fraction of the over a billion websites offer any wireless-compatible content. As the usage of WAP-enabled devices grows, more websites will likely be motivated to create wireless-friendly content.
WAP is designed to operate on any existing wireless service, employing standards such as:
- Short Message Service (SMS)
- High-Speed Circuit-Switched Data (CSD)
- General Packet Radio Service (GPRS)
- Unstructured Supplementary Services Data (USSD)
For more details about these services, visit this page.
Wireless Markup Language
WAP employs Wireless Markup Language (WML), which also incorporates Handheld Device Markup Language (HDML), originally developed by Phone.com.
WML can trace its origins back to eXtensible Markup Language (XML). A markup language adds specific instructions to content, telling the device receiving the content how to interpret it. The most famous markup language is Hypertext Markup Language (HTML). Unlike HTML, WML is classified as a meta language, meaning that, in addition to standard predefined tags, it allows you to create custom markup components. WAP also supports common Internet protocols such as UDP, IP, and XML.
There are three primary reasons why wireless Internet requires the Wireless Application Protocol:
- Transfer rate
- Size and readability
- Navigation
Most mobile phones and web-enabled PDAs have data transfer rates of 14.4 Kbps or lower. To put this in perspective, compare it to a typical 56 Kbps modem, cable modem, or DSL connection. Today’s websites are often loaded with graphics that would take an excruciatingly long time to load at 14.4 Kbps. To address this, wireless internet content is generally designed to be text-based.
The small size of the LCD screens on mobile phones or PDAs presents another challenge. Most websites are designed for a resolution of 640x480 pixels, which works fine for desktops or laptops. However, these pages won’t fit on a wireless device’s display, which might be only 150x150 pixels. Additionally, most wireless devices use monochrome screens, making it harder to read pages where font and background colors blend into similar gray shades.
Navigation is another hurdle. On a traditional computer, you navigate a web page using a mouse to click and point. On a wireless device, however, you typically use one hand to scroll through the page using keys.
WAP accounts for each of these limitations and provides a method for effective use on standard wireless devices.
Wireless Application Protocol
WAP protocol stackHere's the process when you access a website using a WAP-enabled device:
- You power on the device and launch the minibrowser.
- The device emits a radio signal to search for a network connection.
- The device connects to your service provider.
- You choose the website you want to visit.
- A request is sent via WAP to the gateway server.
- The gateway server retrieves the content using HTTP from the website.
- The server encodes the HTTP data in WML format.
- The WML-encoded content is transmitted to your device.
- You view the wireless-friendly version of the selected webpage.
To create wireless internet content, websites produce special versions of their pages that are either text-only or low-graphic. These versions are sent in HTTP format by a Web server to a WAP gateway. The system involves a WAP encoder, script compiler, and protocol adapters that convert the HTTP data into WML. After conversion, the gateway sends the data to the WAP client on your wireless device.
The interaction between the gateway and the client depends on the different features of various components within the WAP protocol stack. Let's examine each of these stack components:
- WAE - The Wireless Application Environment offers the tools that wireless Internet content creators use. These tools include WML and WMLScript, a scripting language that works alongside WML, similar to Javascript.
- WSP - The Wireless Session Protocol determines whether the session between the device and network will be connection-oriented or connectionless. Simply put, it decides if the device needs to continuously communicate with the network during the session. In connection-oriented sessions, data is exchanged both ways, with WSP forwarding packets to the Wireless Transaction Protocol (WTP) layer. For connectionless sessions, used for broadcasting or streaming data from the network, WSP directs packets to the Wireless Datagram Protocol (WDP) layer.
- WTP - The Wireless Transaction Protocol acts as a traffic controller, managing data flow efficiently. It also classifies transaction requests into: Reliable two-way, Reliable one-way, and Unreliable one-way. WSP and WTP layers function similarly to Hypertext Transfer Protocol (HTTP) in the TCP/IP protocol suite.
- WTLS - Wireless Transport Layer Security mirrors the security features of Transport Layer Security (TLS) in TCP/IP. It ensures data integrity, provides encryption, and facilitates client-server authentication.
- WDP - The Wireless Datagram Protocol works in tandem with the network carrier layer (explained below). WDP simplifies WAP’s compatibility with various bearers by modifying only the information at this layer to interface with the bearer.
- Network carriers - Also known as bearers, these include any wireless technologies used by providers, as long as WDP interfaces correctly with the bearer at this level.
Once the WAP client receives the data, it is forwarded to the minibrowser. This small application embedded within the wireless device serves as the user interface for browsing the wireless Internet.
The minibrowser provides only basic navigation features. While wireless Internet is still far from offering the full experience of the regular Internet, it is mainly designed for individuals who need constant connectivity wherever they are. The WAP Forum continues to refine the WAP standard specifications to ensure it develops in a timely and practical manner for users.
