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Greatly expand the information here. Unbreak the build (stray " crept

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in in my last commit).  Eliminate the use of wicontrol to setup hostap
mode.  Warn about using current firmware for hostap.  Describe IBSS
and BSS at least a little bit, as well as the various flavors of
ad-hoc mode.

# This is better, but additional work is still needed.
This commit is contained in:
Warner Losh 2003-01-12 07:12:11 +00:00
parent 66b6052b33
commit cbbbe65b73
Notes: svn2git 2020-12-08 03:00:23 +00:00 
svn path=/head/; revision=15615
1 changed files with 74 additions and 17 deletions

91
en_US.ISO8859-1/books/handbook/advanced-networking/chapter.sgml
View file

@ -492,9 +492,41 @@ host2.example.com link#1 UC 0 0
</sect2>
<sect2>
<title>Wireless Devices</title>
<para>There are two main types of wireless devices: access points, and clients.<para>
<title>Wireless background</title>
<para>There are two different ways to configure 802.11 wireless devices:
BSS and IBSS.</para>
<sect3>
<title>BSS mode</title>
<para>BSS mode is the mode that typically is used. BSS mode is
also called infrastructure mode. In this mode, a number of
wireless access points are connected to a wired network. Each
wireless network has its own name. This name is called the
SSID of the network.</para>
<para>Wireless clients connect to these wireless access
points. The IEEE 802.11 standard defins the protocol that
wireless networks use to connect. A wireless client can be
tied to a specific network, when a SSID is set. A wireless
client can also attach to any network by not excplicitly
setting a SSID.
</sect3>
<sect3>
<title>IBSS Mode</title>
<para>IBSS mode, also called ad-hoc mode, is designed for point
to point connections. There are actually two types of ad-hoc
mode. One is IBSS mode, also called ad-hoc or IEEE ad-hoc
mode. This mode is defined by the IEEE 802.11 standards.
The second is called demo ad-hoc mode or Lucent ad-hoc mode
(and sometimes confusingly ad-hoc mode). This is the old,
pre-802.11 ad-hoc mode and should only be used for legacy
installations.</para>
</sect3>
</sect2>
<sect2>
<title>Infrastructure mode</title>
<sect3>
<title>Access Points</title>
<para>Access points are wireless networking devices that allow one or more wireless
@ -522,6 +554,15 @@ host2.example.com link#1 UC 0 0
(this should not be difficult to find, FreeBSD supports a lot of different
devices). For this guide, we will assume you want to &man.bridge.4; all traffic between
the wireless device and the network attached to the wired network card.</para>
<para>The hostap functionality that FreeBSD uses to implement
the access point works best with certain versions of
firmware. Prism 2 cards should use firmware version 1.3.4
or newer. Prism 2.5 and Prism 3 cards should use firmware
1.4.9. Older versions of the firmware way or may not
function correctly. At this time, the only way to update
cards is with windows firmware update utilities available
from your card's manufacturer.</para>
</sect4>
<sect4>
@ -561,22 +602,20 @@ wi0: flags=8843&lt;UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST&gt; mtu 1500
&prompt.root; <userinput>sysctl net.inet.ip.forwarding=1</userinput></screen>
<para>Now it is time for the wireless card setup.</para>
<para>The following commands will set the card into BSS mode (turning it
into an access point):</para>
<para>The following commands will set the card into an access point:</para>
<screen>&prompt.root; <userinput>wicontrol -s "FreeBSD AP""</userinput>
&prompt.root; <userinput>ifconfig wi0 inet ssid my_net channel 11 media DS/11Mbps mediaopt hostap up</userinput>
<screen>
&prompt.root; <userinput>ifconfig wi0 ssid my_net channel 11 media DS/11Mbps mediaopt hostap up stationname "FreeBSD AP"</userinput>
</screen>
<para>The first &man.wicontrol.8; command tells FreeBSD that the name of this access point
is <literal>FreeBSD AP</literal> by using the <option>-s</option> flag,
Check out &man.wicontrol.8; for more information.</para>
<para>The &man.ifconfig.8; line brings the <devicename>wi0</devicename> interface up, and sets its SSID to <literal>my_net</literal>.
This is a little redundant, but it is shown here to emphasize that you can do
these settings in either place. You will also notice a <option>mediaopt hostap</option> setting;
this setting is to tell &man.ifconfig.8; to put the interface into access point mode.
The <option>media DS/11Mbps</option> is needed so that the <option>mediaopt hostap</option> setting will become effective.
The <option>channel 11</option> sets the 802.11b channel to use. The &man.wicontrol.7;
<para>The &man.ifconfig.8; line brings the <devicename>wi0</devicename> interface up,
sets its SSID to <literal>my_net</literal>,
and sets the station name to <literal>FreeBSD AP</literal>.
The <option>media DS/11Mbps</option> sets the card into 11Mbps mode and is needed
for any <option>mediaopt</option> to take effect.
The <option>mediaopt hostap</option> option places the interface into
access point mode.
The <option>channel 11</option> option sets the 802.11b channel to use. The &man.wicontrol.8;
man page has valid channel options for your regulatory domain.
</para>
@ -586,6 +625,24 @@ wi0: flags=8843&lt;UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST&gt; mtu 1500
<para>It is also suggested that you read the section on encryption that follows.</para>
</sect4>
<sect4>
<title>Status information</title>
<para>Once the access point is configured and operational,
operators will want to see the clients that are associated
with the access point. At any time, the operator may type:</para>
<screen>&prompt.root; <userinput>wicontrol -l</userinput>
1 station:
00:09:b7:7b:9d:16 asid=04c0, flags=3$lt;ASSOC,AUTH>, caps=1$lt;ESS>, rates=f$lt;1M,2M,5.5M,11M>, sig=38/15
</screen>
<para>This shows that there's one station associated, along
with its parameters. The signal indicated should be used
as a realative indication of strength only. Its
translation to dBm or other units varies between different
firmware revisions.</para>
</sect4>
</sect3>
<sect3>
@ -745,7 +802,7 @@ wi0: flags=8843&lt;UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST&gt; mtu 1500
<sect4>
<title>Access Points</title>
<para>The only cards that are currently supported for BSS (as an access point) mode are
devices based on the Prism (or Prism 2, 2.5, 3) chipsets. For a complete list, look
devices based on the Prism 2, 2.5, or 3 chipsets. For a complete list, look
at &man.wi.4;.</para>
</sect4>