Wireless LAN deployment is a significant undertaking partly because there is not a great deal of structure to the process, especially when contrasted with a wired LAN deployment. Building an Ethernet network is straightforward these days. Everybody gets a switched Fast Ethernet (or faster) port, and there is a core switching location that is built on even faster, and possibly aggregated, links. For wiring, there are a number of cabling firms that spend a great deal of time pulling the wire for networks, and enough time has passed so that there is general agreement on the principles by which wiring should be structured.
In comparison, radio networks are the Wild West. Service quality from the network to the end user depends on where the user is in relation to the closest network element, and degrades with distance. Network capacity may be based on the sizes of coverage areas, and the physical layout of the building. Every building has its own personality with respect to radio transmissions, and unexpected interference can pop up nearly everywhere because of microwave ovens, electrical conduits, or severe multipath interference. To make matters worse, the quality of the network medium depends not only on what you do for your wireless LAN, but also what your users do, and even what your neighbors do.
When wireless LAN deployment is considered, you start with the obvious questions: "How many access points do I need, and where do I put them?" To answer those questions, you need to conduct a site survey. Site surveys often are done at the beginning of a wireless LAN project, and are usually a significant part of the project plan for the network. This chapter discusses the intertwined nature of the site survey and the project itself, again from a technical perspective. What do you need to do at the planning stage to make a deployment successful? Planning where to put access points is a part of the wireless LAN roll-out itself, so this chapter helps develop your deployment plan, including developing the physical layout plans.
The process of planning a wireless LAN breaks up into several natural stages. Gathering requirements need not be a long drawn-out process involving the production of many lengthy documents; at the end of the planning process, you should be familiar with the coverage and capacity requirements of the network. Refining requirements and translating them into a physical design consistent with the requirements may take a great deal of time and effort at the site.
Introduction to Wireless Networking
Overview of 802.11 Networks
11 MAC Fundamentals
11 Framing in Detail
Wired Equivalent Privacy (WEP)
User Authentication with 802.1X
11i: Robust Security Networks, TKIP, and CCMP
Contention-Free Service with the PCF
Physical Layer Overview
The Frequency-Hopping (FH) PHY
The Direct Sequence PHYs: DSSS and HR/DSSS (802.11b)
11a and 802.11j: 5-GHz OFDM PHY
11g: The Extended-Rate PHY (ERP)
A Peek Ahead at 802.11n: MIMO-OFDM
Using 802.11 on Windows
11 on the Macintosh
Using 802.11 on Linux
Using 802.11 Access Points
Logical Wireless Network Architecture
Site Planning and Project Management
11 Network Analysis
11 Performance Tuning
Conclusions and Predictions