Wireless access points: consumer, commercial, or DIY?

Sam Leffler sam at freebsd.org
Thu Jul 24 21:48:11 UTC 2008


Mark Bennett wrote:
> Sam,
>
>> FreeBSD HEAD is the only open source system that does Dynamic WDS 
>> (DWDS).  If you want to "bridge to another AP securely" it is the 
>> really the only thing to use. 
>
> I won't argue that your knowledge of the capabilities of FreeBSD 
> wireless surpass mine, and probably that of anyone else.  But I will 
> bring up a couple of points.
>
> First, I have been watching this list and others related to FreeBSD 
> for 2-3 years, as well as working with the O/S when time allows, which 
> is rare.  This is the first time in my recollection that I have seen 
> the term "FreeBSD HEAD" used.  What is that?  It certainly isn't 
> mentioned in the on-line documentation that I can find.  I get a lot 
> of hits when I Google it, but no real definition.

HEAD = "top of trunk"; i.e. the latest code in the tree.

>
> Dynamic Wireless Distribution System I understand.  I also understand 
> I could setup a desktop or laptop as an AP, which is documented very 
> well.  Nothing in the docs on DWDS that I can find.  Maybe that 
> capability is automagically accomplished when two APs are setup?  No, 
> I'm a little too skeptical to believe that.

DWDS is WDS negotiated over a regular infrastucture peering; i.e. you 
piggyback on the normal sta->ap association.  Because there is a normal 
association you can use existing facilities like WPA to secure the WDS 
links.  You also can name endpoints by SSID or whatever and peers follow 
an AP that changes channels (e.g. due to radar detection).  Yes some WDS 
implementations have some of these features but they are basically adhoc 
and don't fit into the original WDS notions where peer relationships are 
fixed and based on BSSID.  If you want to learn about the mechanics 
there are test scripts in the tools/tools/net80211/scripts directory.  
Otherwise I've not written up anything specific.

DWDS was jointly developed with Apple and Atheros and is what Apple uses 
in their Airport+TimeCapsule products.

>
> When I came across dd-wrt I was actually looking for a wireless 
> FreeBSD system embedded on an appliance.  I never found one.  Do you 
> know of one?  I would certainly be interested in that.
>
> dd-wrt is Linux based and I distrust Linux for many reasons, but it's 
> sure better than the firmware that ships with most wireless 
> appliances.  Most hardware APs say they will bridge or relay to 
> another AP, but when you dig into it a little you will find that they 
> only support WEP encryption, which I will not use.  That is a key 
> requirement, at minimum the full support of WPA across the entire 
> network.
>

You get WPA for free w/ DWDS.  The *user-level code* in HEAD is not 
production quality IMO but good enough for demonstration.  At some point 
the code in tools/tools/net80211/wlanwds should be integrated with hostapd.

    Sam



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