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.