Overview of the IEEE 802.11 Standard
This chapter is from the book
This chapter is from the book
This chapter is from the book
The Importance of Standards
Vendors and some end users initially expected markets to dive head first into implementing wireless networks. Markets did not respond as predicted, and flat sales growth of wireless networking components prevailed through most of the 1990s. Relatively low data rates, high prices, and especially the lack of standards kept many end users from purchasing the wire-free forms of media.
For those having applications suitable for lower data rates and enough cost savings to warrant purchasing wireless connections, the only choice before 1998 was to install proprietary hardware to satisfy requirements. As a result, some organizations today still have proprietary wireless networks for which you have to replace both hardware and software to be compliant with the IEEE 802.11 standard. In response to lacking standards, the Institute for Electrical and Electronic Engineers (IEEE) developed the first internationally recognized wireless LAN standard: IEEE 802.11.
Types of Standards
There are two main types of standards: official and public. An official standard is published and known to the public, but it is controlled by an official standards organization, such as IEEE. Government or industry consortiums normally sponsor official standards groups. Official standards organizations generally ensure coordination at both the international and domestic level.
A public standard is similar to an official standard, except it is controlled by a private organization, such as the Wireless LAN Interoperability Forum. Public standards, often called de facto standards, are common practices that have not been produced or accepted by an official standards organization. These standards, such as TCP/IP, are the result of widespread proliferation. In some cases, public standards that proliferate, such as the original Ethernet, eventually pass through standards organizations and become official standards.
Companies should strive to adopt standards and recommended products within their organizations for all aspects of information systems. What type of standards should you use? For most cases, focus on the use of an official standard if one is available and proliferating. This will help ensure widespread acceptance and longevity of your wireless network implementation. If no official standard is suitable, a public standard would be a good choice. In fact, a public standard can often respond faster to changes in market needs because it usually has less organizational overhead for making changes. Be sure to avoid non-standard or proprietary system components, unless there are no suitable standards available.
Case Study 3.1:
802.11 Versus Proprietary Standards
A large retail chain based in Sacramento, California, had requirements to implement a wireless network to provide mobility within its 10 warehouses located all over the U.S. The application called for clerks within the warehouse to use new handheld wireless data collectors that perform inventory management functions.
The company, already having one vendor's data collection devices (we'll call these brand X), decided to use that vendor's brand Y proprietary wireless data collectors and its proprietary wireless network (the vendor didn't offer an 802.11-compliant solution). This decision eliminated the need to work with additional vendors for the new handheld devices and the wireless network.
A year passed after the installation, and enhancement requirements began to pour in for additional mobile appliances that were not available from the brand X vendor. This forced the company to consider the purchase of new brand Z appliances from a different vendor. The problem, though, was that the brand Z appliances, which were 802.11-compliant, didn't interoperate with the installed proprietary brand Y wireless network. Because of the cost associated with replacing its network with one that was 802.11-compliant (the brand Y wireless network had no upgrade path to 802.11), the company couldn't implement the new enhancement cost effectively.
The company could have eliminated the problem of not being able to implement the new enhancement if it would have implemented the initial system with 802.11-compliant network components because most vendors offer products that are compatible with 802.11, but not all the proprietary networks. The result would have been the ability to consider multiple vendors for a wider selection of appliances.
Institute for Electrical and Electronic Engineers (IEEE)
The IEEE is a non-profit professional organization founded by a handful of engineers in 1884 for the purpose of consolidating ideas dealing with electrotechnology. The IEEE plays a significant role in publishing technical works, sponsoring conferences and seminars, accreditation, and standards development. With regard to LANs, the IEEE has produced some very popular and widely used standards. For example, the majority of LANs in the world use network interface cards based on the IEEE 802.3 (ethernet) and IEEE 802.5 (token ring) standards.
Before someone can develop an IEEE standard, he must submit a Project Authorization Request (PAR) to the IEEE Standards Board. If the board approves the PAR, IEEE establishes a working group to develop the standard. Members of the working groups serve voluntarily and without compensation, and they are not necessarily members of the institute. The working group begins by writing a draft standard and then submits the draft to a balloting group of selected IEEE members for review and approval. The ballot group consists of the standard's developers, potential users, and other people having a general interest.
Before publication, the IEEE Standards Board performs a review of the Final Draft Standard and then considers approval of the standard. The resulting standard represents a consensus of broad expertise from within IEEE and other related organizations. All IEEE standards are reviewed at least once every five years for revision or reaffirmation.
NOTE
In May 1991, a group led by Victor Hayes submitted a Project Authorization Request (PAR) to IEEE to initiate the 802.11 working group. Hayes became chairman of the working group and led the standards effort to its completion in June 1997.
Benefits of the 802.11 Standard
The benefits of using standards such as those published by IEEE are great. The following sections explain the benefits of complying with standards, especially IEEE 802.11.
Appliance Interoperability
Compliance with the IEEE 802.11 standard makes possible interoperability between multiple-vendor appliances and the chosen wireless network type. This means you can purchase an 802.11-compliant scanner from Symbol and a Pathfinder Ultra handheld scanner/printer from Monarch Marking Systems and they will both interoperate within an equivalent 802.11 wireless network, assuming 802.11 configuration parameters are set equally in both devices. Standard compliance increases price competition and enables companies to develop wireless LAN components with lower research and development costs. This enables a greater number of smaller companies to develop wireless components.
As shown in Figure 3.1, appliance interoperability prevents dependence on a single vendor for appliances. Without a standard, for example, a company having a non-standard proprietary network would be dependent on purchasing only appliances that operate on that particular network. With an 802.11-compliant wireless network, you can use any equivalent 802.11-compliant appliance. Because most vendors have migrated their products to 802.11, you have a much greater selection of appliances for 802.11 standard networks.
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Fast Product Development
The 802.11 standard is a well-tested blueprint that developers can use to implement wireless devices. The use of standards decreases the learning curve required to understand specific technologies because the standard-forming group has already invested the time to smooth out any wrinkles in the implementation of the applicable technology. This leads to the development of products in much less time.
Figure 3.1 Appliance interoperability ensures that multiple-vendor appliances will communicate over equivalent wireless networks.
Stable Future Migration
Compliance with standards helps protect investments and avoids legacy systems that must be completely replaced in the future as those proprietary products become obsolete. The evolution of wireless LANs should occur in a fashion similar to 802.3, Ethernet. Initially, Ethernet began as a 10Mbps standard using coaxial cable media. The IEEE 802.3 working group enhanced the standard over the years by adding twisted-pair, optical fiber cabling, and 100Mbps and 1000Mbps data rates.
Just as IEEE 802.3 did, the 802.11 working group recognizes the investments organizations make in network infrastructure and the importance in providing migration paths that maximize the installed base of hardware. As a result, 802.11 will certainly ensure stable migration from existing wireless LANs as higher-performance wireless networking technologies become available.
Price Reductions
High costs have always plagued the wireless LAN industry; however, prices have dropped significantly as more vendors and end users comply with 802.11. One of the reasons for lower prices is that vendors no longer need to develop and support lower-quantity proprietary subcomponents, cutting-edge design, manufacturing, and support costs. Ethernet went through a similar lowering of prices as more and more companies began complying with the 802.3 standard.
Avoiding Silos
Over the past couple of decades, MIS organizations have had a difficult time maintaining control of network implementations. The introduction of PCs, LANs, and visual-based development tools has made it much easier for non-MIS organizations, such as finance and manufacturing departments, to deploy their own applications. One part of the company, for example, may purchase a wireless network from one vendor, then another part of the company may buy a different wireless network. As a result, silos--non-interoperable systems--appear within the company, making it very difficult for MIS personnel to plan and support compatible systems. Some people refer to these silos as stovepipes.
Acquisitions bring dissimilar systems together as well. One company with a proprietary system may purchase another having a different proprietary system, resulting in non-interoperability. Figure 3.2 illustrates the features of standards that minimize the occurrence of silos.
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Figure 3.2 Compliance with the IEEE 802.11 standard can minimize the implementation of silos.
Case Study 3.2:
Problems with Mixed Standards
A company located in Barcelona, Spain, specializes in the resale of women's clothes. This company, having a MIS group without much control over the implementation of distributed networks in major parts of the company, has projects underway to implement wireless networks for an inventory application and a price-marking application.
Non-MIS project managers located in different parts of the company lead these projects. They have little desire to coordinate their projects with MIS because of past difficulties. As a result, both project managers end up implementing non-compatible proprietary wireless networks to satisfy their networking requirements.
The project managers install both systems: one that covers the sales floor space of their 300 stores (for price marking) and one that encompasses 10 warehouses (for doing inventory functions). Even though the systems are not compatible, all is fine for the users operating the autonomous systems.
The problems with this system architecture, though, are the difficulty in providing operational support and inflexibility. The company must maintain purchasing and warranty contracts with two different wireless network vendors, service personnel will need to acquire and maintain an understanding of the operation of two networks, and the company will not be able to share appliances and wireless network components between the warehouses and the stores.
As a result, the silos in this case make the networks more expensive to support and limit their flexibility in meeting future needs. The implementation of standard 802.11-compliant networks would have avoided these problems.