====== Wifi Notes ======

This page is largely a personal collection of notes from my discussions with [[/AdrianChadd|AdrianChadd]] on the %%FreeBSD%% wireless networking stack and how to work effectively with the stack.

==== Debugging pre-requisites ====

  * Enable ''%%iwn(4)%%'' debugging to syslog with ''%%sysctl dev.iwn.0.debug=0x1%%''
  * Ensure you have a kernel with ''%%option IWN_DEBUG%%'' added

==== Debugging with experimental traffic ====

In order to verify the rates and performance of the ''%%iwn(4)%%'' it is recommended that you have a local wireless network (WLAN) which attaches to a traditional LAN. The network should look something like this:

<code>
          +––––––––––––––––+                           
          | Router/Gateway |                           
          +––––––––––––––+–+                           
                  ^      |                             
                  |      |    +–––––––––––––+          
                  |      +–––>+ Wireless AP |          
                  |           +–––––––––––+–+          
                  |                       v            
+–––––––––––––––––+–––+              +––––+–––––––––––+
| FreeBSD workstation |              | FreeBSD laptop |
+–––––––––––––––––––––+              +––––––––––––––––+

</code>

  * On the workstation set up [[http://www.freshports.org/benchmarks/iperf/|iperf]]
  * Enable the debugging flags above on the laptop
  * Use iperf + UDP to determine whether the laptop is seeing sends or receives experience performance degradation

==== Disorganized Notes ====

  * Look at iwn_rate_to_plcp() for reversing the plcp debug flag (if_iwn.c)
  * Look at TX_STATUS code for the status flag (if_iwnreg.h)
  * Learn how to compile the wireless stack as modules entirely instead of in the kernel object