I have been running a very similar setup for several years now, a net5501 with 
a Ralink RT2561S card, with the machine being used as a firewall (NAT box), 
router, DNS/DHCP/NTP server, wireless AP, Squid proxy, file and web server for 
the home, and a few other functions.  I've been running OpenBSD, because it is 
so well audited and secure.  It is also very cleanly organized and easy to 
administer, partially because things are minimalist.  Unfortunately, my 
hardware has become obsolete (disk capacity and age issues, not enough memory 
for some services, and an OS upgrade is urgently needed).

There is, however, one huge problem with OpenBSD, which partially exists in the 
other *BSD versions too.  Wireless clients can go into something called "power 
saving mode", in which the AP has to hold packets for the client back (because 
the client has turned off its receive circuits), until the next "beacon" packet 
that wakes the client.  Unfortunately, OpenBSD does *not* support clients in 
power saving mode.  And while clients (typically laptops and smartphones) that 
run Windows or Linux can be configured to not go into power saving mode, this 
is not possible for Apple devices (both MacOS and iOS).  This causes latency 
and throughput to MacBooks and iPhones to be horrible, as the missing packets 
have be retransmitted at a higher layer of the TCP/IP stack.  OpenBSD has no 
plans to support power saving mode when running as an AP.  This means that at 
my next install, I will abandon OpenBSD, and switch to another OS.  I want to 
stick with the *BSD family, as Linux has over the 
 decades become a disorganized mess to administer, maybe even worse than 
Windows.

Fortunately, FreeBSD supports power saving mode, but that support seems to be 
restricted to only certain device drivers.  Another question is support for 
802.11n with multi-antenna (MIMO) and beam forming.  Not clear to me how well 
this works coming from a miniPCIe card with a potentially mismatched set of 
antennas.  But I'm also not sure that the bandwidth gains from MIMO and beam 
forming are sensible in a residential environment; it depends heavily on the 
usage model, which can vary widely.  Which immediately raises the question you 
bring up: which wireless card to buy.  II have not yet found one up-to-date 
place that shows which FreeBSD wireless drivers have what capabilities, and how 
that works with external antennas.

All I'm saying here is that you should research these questions before ordering 
the 802.11 hardware for your home-built AP.  I'm no longer even sure that in 
the age of 802.11n MIMO, building your own AP is still sensible.  The tradeoffs 
between complexity, power consumption, cost, performance, and setup and support 
labor are not obvious.

--
Ralph Becker-Szendy     408-395-1435     [email protected]
735 Sunset Ridge Road; Los Gatos, CA 95033




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