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CHAPTER 6 Planning and Designing Wireless Data and Satellite Applications Copyright 2003 by The McGraw-Hill Companies, Inc. Click Here for Terms of Use. 156 Part 2: Planning and Designing Data Applications As you know, wireless data networks are composed of two components— access points and client devices. The components communicate with each other via radio-frequency transmissions, eliminating the need for cabling. So, what do you need to plan, design, and build a wireless data net-work? Let’s take a look. Access Points A wireless data network is planned, designed, and built around one or more access points that act like hubs, which send and receive radio sig-nals to and from PCs equipped with wireless data client devices. The access point can be a stand-alone device, forming the core of the network, or it can connect via cabling to a conventional local-area network (LAN). You can link multiple access points to a LAN, creating wireless data seg-ments throughout your facility. (The Glossary defines many technical terms, abbreviations, and acronyms used in the book.) Client Devices To communicate with the access point, each notebook or desktop PC needs a special wireless data networking card. Like the network inter-face cards (NICs) of cabled networks,3 these cards enable the devices to communicate with the access point. They install easily in the PC slots of laptop computers or the PCI slots of desktop devices, or link to USB ports. A unique feature found on the wireless data PC card of a leading vendor features a small antenna that retracts when not in use. This is extremely beneficial, given the mobility of laptop computers. You can also connect any device that doesn’t have a PC or PCI card slot to your wireless data network by using an Ethernet client bridge that works with any device that has an Ethernet or serial port (print-ers, scanners etc.). Once the access point is plugged into a power outlet and the net-worked devices are properly equipped with wireless data cards, network connections are made automatically when the devices are in range of the hub. The range of a wireless data network in standard office environ-ments can be several hundred feet. Wireless data networks operate like wired networks and deliver the same productivity benefits and efficiencies. Users will be able to share files, applications, peripherals, and Internet access. Chapter 6: Planning, Designing Data, Satellite Applications 157 Planning and Designing a Wireless Data Network Now, what type of features should you plan and design into a wireless data network? In other words, you need to plan, design, and build the following features and solutions: Standards-based and WiFi certified Simple to install Robust and reliable Scability Ease of use Web server for easy administration Security A site survey application Installation Standards-Based and WiFi Certified As previously explained, WiFi is a robust and proved industry-wide net-work standard that ensures your wireless data products will interoper-ate with WiFi-certified products from major networking vendors. With a WiFi-based system, you will have compatibility with the greatest num-ber of wireless data products and will avoid the high costs and limited selection of proprietary, single-vendor solutions. Additionally, select a wireless solution that is standards based and fully interoperable with Ethernet and Fast Ethernet networks. This will enable your wireless data network to work seamlessly with either your existing cabled LAN or one that you deploy in the future. Simple to Install Your wireless data solution should be plug and play, requiring only min-utes to install. Plug it in and start networking. For even greater ease of deployment, your solution should support the Dynamic Host Configura-tion Protocol (DHCP), which will automatically assign IP addresses to wireless data clients. Rather than install a DHCP server in a stand-alone device to provide this timesaving capability, select wireless data hubs that feature DHCP servers built into them. 158 Part 2: Planning and Designing Data Applications If you are adding a wireless data system onto your existing Ethernet net-work, an access point that can be powered over standard Ethernet cabling makes a great choice. This enables you to run the access point using low-voltage dc power over the same cabling you use for your data—eliminating the need for a local power outlet and power cable for each access point device. Robust and Reliable Consider robust wireless data solutions that have ranges of at least 300 ft. These systems will provide your employees with considerable mobility around your facility. You may choose a superior system that can automati-cally scan the environment to select the best radio-frequency (RF) signal available for maximum communications between the access point and client devices. To guarantee connectivity at the fastest possible rate, even at long range or over noisy environments, make sure your system will dynamically shift rates according to changing signal strengths and dis-tance from the access point. Additionally, select wireless data PC cards for your laptop computers that offer retractable antennas to prevent break-age when the devices are moved about. Scalability A good wireless data hub should support approximately 60 simultaneous users. This should enable you to expand your network cost-effectively simply by installing wireless data cards in additional computers and network-ready printers. For printers or other peripherals that do not support networking, you should connect them to your wireless data net-work with a wireless USB adapter or an Ethernet client bridge. Ease of Use A wireless data network should be as effortless for users to operate as a cabled network. To ensure maximum performance and reliability at all times, chose a system that can automatically scan the local environment to select the strongest available radio-frequency channel for communications. If you plan to connect multiple wireless data hubs to an existing cabled network, consider a solution that features automatic network connections. When a user roams beyond the boundaries of one wireless data hub into the range of another, an automatic network connection capability will seamlessly transfer the user’s communications to the lat- Chapter 6: Planning, Designing Data, Satellite Applications 159 ter device, even across router boundaries, without ever reconfiguring the IP address manually. This is particularly useful for businesses with mul-tiple facilities that are connected via the wide-area network (WAN). As a result, users will be able to move about your facility and beyond freely and remain connected to the network. Web Server for Easy Administration You will simplify administration of your wireless data network if you select an access point with a built-in Web server. This allows you to access and set configuration parameters, monitor performance, and run diagnostics from a Web browser. Security Choose a wireless data solution that offers multiple security layers, including encryption and user authentication. A secure solution will offer at least 40-bit encryption, and advanced systems can provide 128-bit encryption. For both ease of use and the strongest protection, select a superior solution that automatically generates a new 128-bit key for every wireless data networking session without users entering a key manually. Also, consider a system that features user authentication, requiring work-ers to enter a password before accessing the network. A Site Survey Application Your wireless data networking solution should include a site survey utility. The utility can help you determine the optimal location of wireless data hubs and the number of hubs you need to support your users. It will help you to deploy a wireless data solution effectively and efficiently. Installation Do you need a technician to install your wireless data network? Generally, you can install a wireless data network yourself. A wireless data solution is an effective strategy if your organization lacks networking experience. Some advanced systems can be set up in a minute or so. Installation and deployment procedures are discussed in specific detail in Part 3, “Installing and Deploying Wireless High-Speed Data Networks” (Chaps. 13 to 17). ... - tailieumienphi.vn
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