Webmaster's Guide to the Wireless Internet part 8

42 Chapter 1 · Moving from the Web to Wireless Above all, the major shift in perspective required of the wireless Webmaster is to realize that you’re authoring for a mobile audience, not just mobile devices. Rather than simply using portable devices, visitors to your site may actually be on the move, whether walking down the street or in a vehicle.They’re probably not donating 100 percent of their attention to the screen, and likely only have one hand for navigation. In this situation, the browsing model of the wired Web will not work. Users need simplified, quick access to just the information they need, in a concise format that downloads quickly.This is not simply a matter of shortening text and optimizing graphics; successful mobile Web sites need to pro-vide mobile users immediate access to just the information they need, when they need it, from anywhere and from any device. www.syngress.com Moving from the Web to Wireless · Chapter 1 43 Summary The wireless Web represents a revolution in access to online information that will have profound impact on our society—greater even than the Internet revolution of the past decade.Although the skills learned byWebmasters over the short but tumultuous life of the Web will provide a solid foundation for this new world, new skills will have to be developed and some old habits changed. The sheer variety of different mobile devices is the first big change a Webmaster will have to deal with, making the “browser wars” of the last few years seem like child’s play. However, you’ll find that devices fall into a few gen-eral families with similar characteristics, simplifying the presentation task some-what. Device detection, coupled with on-the-fly, server-side generation of markup is one way to solve this problem. Here, XML transformed to appropriate markup via XSL, provides a future-proof option. How users connect to your site can be as important as which device they use. The majority of current mobile devices are limited to wireless speeds of between 9.6 Kbps to 19.2 Kbps, with few exceptions.These connections are also inher-ently unreliable, with long call setup times and latency.You’ll need to modify your content and navigation to compensate for these limitations.The walled garden approach of carriers, coupled with the inevitable backlash against WAP when users discovered it didn’t live up to the early hype, has left a lot of users disillu-sioned with WAP, but newly available wireless options for PDAs and laptops have revived interest in mobile computing.With the huge surge in interest in wireless data services—particularly from corporate users—carriers continue to offer newer and faster connectivity options. 2.5G services such as GPRS are already being rolled out worldwide, and we can look forward to the much higher data speeds of 3G introducing a world of broadband wireless within the next two to four years. For the purposes of the wireless Webmaster looking to provide content for mobile users, mobile wireless devices can be classified into three families: mobile phones, PDAs, and laptops. Mobile phones have tiny screens and slow data speeds—9.6 Kbps is the current top speed on most networks. User interaction is difficult, requiring users to enter data with a nine-key numeric keypad. However, these are still the most prevalent wireless devices in circulation. In the U.S. and Europe,WAP is the predominant means of delivering Internet content to mobile phones.WAP compiles content to optimize transmission over wireless connec-tions, but it is still slow and difficult to use on current networks. Japan has had www.syngress.com 44 Chapter 1 · Moving from the Web to Wireless huge success with a similar service called i-Mode, but as yet this doesn’t seem to have made much impact outside of Japan. PDAs are a step up in functionality, providing relatively larger screens, color display, and support for both handwriting recognition and virtual keyboards. Currently, PDAs are split into the subclasses of either Palm OS or Pocket PC, each of which has different display capabilities, memory, and processing power. PCMCIA and Compact Flash modems are widely available for both varieties of PDA, offering data speeds up to 19.2 Kbps or even 28.8 Kbps. The same wireless options available to PDA users also offer the possibility of wireless Internet access to laptop users. Here, users have the benefit of large, full-color screens and full keyboard/mouse interaction, but you’ll still need to be aware of their relatively slower data speeds and adapt your content to suit. The mobile wireless landscape is in a state of rapid flux, with new devices announced almost monthly. Hybrid devices attempt to combine the mobility and voice capabilities of mobile phones with the organizational capabilities of PDAs. Unfortunately, these tend to compromise the capabilities of each. Microsoft Stinger is one device to watch, although its impact is still uncertain.Tablet PC holds some promise as a next-generation mobile device, but is not yet available to end-users.Voice interaction is another emergent technology that could radically affect the job of the wireless Webmaster. Despite the wide range of new devices and connection options, a certain amount of overlap still exists with the skills Webmasters have developed on the wired Web. HTML, with some modifications, is still a very viable option for both Pocket PC and Palm OS PDAs, and WML should present no major problems for a competent Web coder. XHTML, XML, and XSL are the next evolution in markup, and wireless Webmasters would do well to become proficient in these technologies. Location-based services are another new area worth exploring, uti-lizing technologies such as GPS to customize content for a users physical loca-tion. Personalization is another option for users with less time and limited screen sizes and access speeds. Perhaps the largest change required of Webmasters is to adapt UI and presen-tation to suit the different needs of mobile users, who need rapid access to tar-geted information, rather than the browsing paradigm of the wired Web. In most cases, this means rethinking both content presentation and user interaction, rather than simply formatting with a new markup language. QA testing is important, to ensure a satisfactory user experience. www.syngress.com Moving from the Web to Wireless · Chapter 1 45 Solutions Fast Track Explaining Wireless The emphasis on mobility is one of the defining characteristics of this new wireless paradigm, and from a Webmaster’s point of view this mobility, not simply the lack of wires, is likely to be the most important aspect you have to deal with. Low bandwidth, differing standards, multiple network carriers, and a multitude of radically different devices means that the job of the wireless Webmaster just got immensely more complicated. Types of Wireless Connectivity The Wireless Application Protocol (WAP) is the first widely available method of accessing Internet content from a mobile device.WAP gateways enable legacy browsers to understand WML content. However, due to differences in the WAP gateway configuration, and the particular microbrowser installed on the handset, a WAP page may display differently on different handsets. With Short Message Service (SMS), users can send short text messages to each other at a fraction of the cost of a voice call. SMS can also be used to send configuration settings to your phone. SMS is a huge success in Europe, and it is gradually becoming available on U.S. wireless phone plans, although in a limited fashion. Japan’s NTT DoCoMo mobile data service i-Mode offers users the ability to browse a huge range of Web sites with cheap, full-color handsets that maintain an always-on connection to the Internet. It could possibly become an alternative to WAP but currently is in use only in Japan. The European wireless standard, Global System for Mobile Communications (GSM), is available on a limited basis in the US.The General Packet Radio System (GPRS) will soon offer higher data speeds and an always-on connection worldwide; it is already available in some European countries, and on a trial basis in a few U.S. cities. www.syngress.com 46 Chapter 1 · Moving from the Web to Wireless A recent option for wireless connectivity in the U.S. is Cellular Digital Packet Data (CDPD), a packet-switched network this is an always-on connection.The major drawback of CDPD is limited availability. The 802.11b standard has found ready acceptance as a short-range radio replacement for traditional Ethernet connections. Bluetooth is another short-range wireless standard. Evolving Mobile Devices The three main categories of mobile devices, mobile phones, PDAs, and laptop computers, are differentiated by connectivity, screen size, memory, and processing power. Data-capable phones use the WAP protocol, and content needs to be coded in Wireless Markup Language (WML).They have minimal requirements for memory and processing power.A mobile phone never communicates directly with your Web server; there is always a WAP gateway acting on its behalf (the gateway may alter the content somewhat on its way through). The market for Personal Digital Assistants (PDAs) is split mainly between those running the Palm operating system from both Palm, Inc. and its licensees, and devices based on Microsoft’s Pocket PC or Windows CE. One feature of Pocket PCs that’s especially relevant to wireless is that most come with an industry-standard expansion slot, either CF or PCMCIA Type II. PDAs come in a wide range of configurations of connectivity, screen size, memory, and processing power. Several manufacturers have begun shipping laptops with built-in wireless LAN (802.11b) cards, with antennas integrated into the casing.These same manufacturers will soon begin offering Bluetooth-equipped laptops. However, with larger screens, keyboards, and more memory and storage, Handheld PCs are beginning to offer a viable alternative to bulky laptops. Also, several devices are available that seek to combine aspects of each category—a mobile phone with an integrated Palm screen, PDAs that can be used as phones, and laptop-size devices without keyboards that you use by writing directly on the screen. www.syngress.com ... - tailieumienphi.vn