Conventionally speaking, internetworking has been accomplished by plugging cables into electronic boxes and then letting packets fly. But one of the latest, greatest additions to networking gives packets their own wings. They need no longer be constrained by the physical limit of the twisted-pair wiring. The era of wireless networking is upon us.
With all the advances in conventional, wired networking, it was only a matter of time before someone looked up into the sky and wondered, "What about wireless?" Truth be told, someone asked that question more than a decade ago, but the practical, functional result of that question has only been realized in the last couple of years.
In this section, we take a look back at where wireless networking came from, how it works, and how you can benefit from it.
To understand better the wireless networking of today, it's important to know its history and how we've gotten here from there.
The most popular LAN technology in the world is Ethernet. It is defined by the Institute of Electrical and Electronic Engineers (IEEE) with the 802.3 standard. Ethernet has provided an evolving, widely available, high-speed networking standard. Initially, Ethernet provided 1 Mbps, and then 10 Mbps transfer rates, which then grew to 100 Mbps, and then 1 Gbps, and are now at 10 Gbps. Because IEEE 802.3 is an open standard, there is a broad range of suppliers and products for Ethernet users. The standard ensures a certain level of interoperability, no matter what the product or vendor.
The first wireless LAN (WLAN) technologies weren't as speedy as Ethernet at the time. They operated in the 900-MHz band and only clocked in at about 2 Mbps, max. Furthermore, they were proprietary in nature, which eliminated any common communication between different vendors' products. In spite of these obstacles, wireless networking managed to carve out a respectable niche for itself in vertical markets like retail and warehousing. It was useful in these environments, because the mobility and flexibility of the technology was necessary in environments where the workers used handheld devices for such activities as inventory management and data collection.
Aironet, a wireless networking company, realized the need for wireless networking and began pushing for standards in 1991.
Cisco acquired Aironet in 2000 and uses its technology as the cornerstone of its WLAN products. We talk about Cisco's acquisition and their Aironet devices later in the chapter.
By establishing standards, they argued, wireless LANs would gain broad market acceptance. The next year, WLAN developers began working on products that operated in the unlicensed 2.4-GHz frequency band. This new technology was especially appealing to two particular markets:
Health care Wireless networking made it possible to transfer patient data to mobile computing devices. Rather than tote a computer from exam room to exam room, wireless networking puts patient information at a health care professional's fingertips.
Schools Not being constrained by wires made it possible for schools that were constructed without wiring conduits (remember the days) to construct computer networks without having to punch holes in walls and string cabling between floors.
In June 1997, the technology that serves as the core standard for the WLANs we know today was developed. The IEEE released the 802.11 standard for wireless local area networking. The standard supports data transmission in infrared light and two types of radio transmission within the unlicensed 2.4-GHz frequency band: Frequency Hopping Spread Spectrum (FHSS) and Direct Sequence Spread Spectrum (DSSS).
We'll get deeper into 802.11 specifics later in the chapter.
If the simple ability to perform networking functions without being tethered to a switch or a hub isn't enough to stir your soul, let's take a closer look at the abilities of wireless data transmission, along with a few situations in which wireless networking is beneficial.
Besides the "gee-whiz, this is kewl" aspect of a computer network that operates without wires, there are a number of important factors that make wireless networking a useful, productive technology:
Mobility With WLANs, users can get real-time access to their LAN from virtually anywhere (depending on your range and any obstacles and interference). This ability comes without having to be hardwired into the network. This mobility gives users the freedom to access the network from almost anywhere at any time.
Reduced cost-of-ownership Even though start-up costs for WLAN hardware are more than the cost of a traditional LAN, when the complete, lifecycle expenses are considered, WLAN expenses can be considerably lower. The greatest long-term cost benefits are seen in dynamic environments where there are frequent moves and changes.
Scalability WLANs can be easily configured in a number of networking topologies to meet the needs of specific applications and installations. Configurations are highly flexible, can easily be changed, and range from simple peer-to-peer networks that are ideal for a few users to full infrastructure networks of thousands of users that enable roaming across a broad area.
High-Speed Data Rates WLAN transmission speeds are starting to be comparable to wired networks. Users can access information at 54 Mbps, which is on par with conventional wire speeds. Though not yet touching the 100 Mbps, 1 Gbps, and 10 Gbps that are possible in wired networks, wireless has a respectable, functional speed.
Interoperability Manufacturers (like Cisco) who build their products using the 802.11 standard ensure functionality with other compliant equipment or brands within the network.
Encryption for high-speed LAN security By incorporating WPA and WPA2 schemes, network security can be ensured. WPA/WPA2 serves access points (APs), PC cards, ISA cards, and PCI adapters.
Installation speed and simplicity Before wireless technology, connecting computers to a LAN required stringing and plugging in a mess of wires. The task could be further complicated if the wiring needed to be strung through walls or between different floors. Wireless technology simplifies and speeds up the installation process.
Installation Flexibility Because WLANs aren't restricted by the physical barriers that constrain wired LANs, wireless networks can provide network access to those users and workstations where connecting to a LAN is simply impossible.
Given the continually changing face of technology and its applications, it almost seems silly to pigeonhole a specific technology into specific fields. However, the following list will give you an idea of how wireless technology can be used in a number of different fields. Again, this list should not be considered as the extent of wireless' capabilities-your own circumstances and situations will be the best guide as to whether you benefit most from a wireless or wired networking:
Corporate With a WLAN, corporate employees need no longer be tethered to their desks. By using laptops equipped with wireless NICs (network interface cards), they can take full advantage of e-mail, file sharing, and Web browsing, regardless of where they are in the office or business campus.
Hospitality and retail Hospitality services-like restaurants-can use WLANs to enter and send food orders to the kitchen, directly from the table. Retail stores can use WLANs to set up temporary cash registers for special events, like the day after Christmas or the start of a sale.
Manufacturing WLANs link factory floor workstations and data collection devices to a company's network. They are mobile on the work floor and don't require more cabling on the factory floor.
Warehousing WLANs connect handheld and forklift-mounted computer terminals with barcode readers and wireless data links. This technology is used to enter and maintain the location of a warehouse's inventory.
Education Schools, colleges, and universities benefit from mobile connectivity by enabling students, faculty, and staff with notebook computers to connect to the academic institution's network for collaborative lessons, and to the Internet for Web browsing and e-mail. Furthermore, wireless technology can save desperately needed classroom space by making portable computer labs a reality.
Financial Financial traders can use a handheld PC with a WLAN adapter to receive pricing information from a database in real time and to speed up and improve the quality of trades.
Health care By using wireless handheld PCs, health care professionals have access to real-time information and can increase productivity and quality of patient care by reducing treatment delays, roaming from patient to patient, and eliminating redundant paperwork and decreasing transcription errors.
This is just the tip of the iceberg on how wireless networking can be used. To be sure, as technology changes the face of business, more and more uses for wireless networking will be apparent.