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11 Network Analysis

Network Analysis

There is no coming to consciousness without pain.

Attributed to C.G. Jung

In the 1990s, computer professionals joined doctors as People With Answers. Just as doctors are asked medical questions by complete strangers, computer professionals are asked a bewildering variety of technical questions by complete strangers. When these strangers learn that I work with networks, I am often asked, "Why does the Internet break so often?" The more I contemplate the question, the more I believe that the question should be, "Why doesn't the Internet break more often?"

While I could never hope to answer either question in a single chapter of a book, it is obvious that network problems are a fact of life. Networks break, and wireless networks are no exception. Wireless LANs can improve productivity, but they also carry a larger risk of complete outage, and the limited bandwidth is almost sure to be overloaded. After building a wireless LAN, network engineers must be ready to investigate any problems that may arise.

As in many other network types, the trusty network analyzer is a key component in the engineer's toolbox. Network analyzers already exist for the wired backbone side of the wireless network and can be used productively in many troubleshooting scenarios. Wireless network troubleshooting depends on having a network analyzer for exactly the same reason. Sometimes, you just need to have a way of seeing what is on the airwaves. This chapter is devoted to tools that allow network engineers to do just that. Several commercial analyzers are available, and there are free tools that run on Linux. Before diving into the tools, though, it may help to consider why wireless network analyzers are a practical requirement for the network administrator.

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

Management Operations

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

11 Hardware

Using 802.11 on Windows

11 on the Macintosh

Using 802.11 on Linux

Using 802.11 Access Points

Logical Wireless Network Architecture

Security Architecture

Site Planning and Project Management

11 Network Analysis

11 Performance Tuning

Conclusions and Predictions

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802.11 Wireless Networks The Definitive Guide
802.11 Wireless Networks: The Definitive Guide, Second Edition
ISBN: 0596100523
EAN: 2147483647
Year: 2003
Pages: 179
Authors: Matthew Gast
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