In this lab, we’ll investigate the

In this lab, we’ll investigate the 802.11 wireless network protocol. Before beginning this
lab, you might want to re-read Section 6.3 in the text. Since we’ll be delving a bit deeper
into 802.11 than is covered in the text, you might want to check out “A Technical
Tutorial on the 802.11 Protocol,” by Pablo Brenner (Breezecom Communications),
http://www.sss-mag.com/pdf/802_11tut.pdf, and “Understanding 802.11 Frame Types,”
by Jim Geier, http://www.wi-fiplanet.com/tutorials/article.php/1447501. And, of course,
there is the “bible” of 802.11 - the standard itself, “ANSI/IEEE Std 802.11, 1999 Edition
(R2003),” http://gaia.cs.umass.edu/wireshark-labs/802.11-1999.pdf. In particular, you
may find Table 1 on page 36 of the standard particularly useful when looking through the
wireless trace.
In all of the Wireshark labs thus far, we’ve captured frames on a wired Ethernet
connection. Here, since 802.11 is a wireless link-layer protocol, we’ll be capturing frames
“in the air.” Unfortunately, most of the device drivers for wireless 802.11 NICs
(particularly for Windows operating systems) don’t provide the hooks to capture/copy
received 802.11 frames for use in Wireshark (see Figure 1 in Lab 1 for an overview of
packet capture). Thus, in this lab, we’ll provide a trace of captured 802.11 frames for you
to analyze and assume in the questions below that you are using this trace. If you’re able
to capture 802.11 frames using your version of Wireshark, you’re welcome to do so.
Additionally, if you’re really into frame capture, you can buy a small USB device,
AirPcap, http://www.cacetech.com, that captures 802.11 frames and provides integrated
support for Wireshark under Windows.