[CALUG] Next meeting (and will Walt be there?) -- WAS: asus wifi

Bryan J Smith b.j.smith at ieee.org
Fri Dec 24 15:20:35 EST 2010


BTW, when's the next meeting?  I need to make it out.  There's only so much I 
can do in e-mail.  I'm driving back from my Florida home the first week of 
January, after making a pit stop in Memphis for a bowl game (yeah, a bit of a 
detour from driving straight up I-95).


I hate it when I see people have issues this long, and I'm sure it's just some 
simple stuff that the user will quickly understand if I showed it in person.  
Especially since I may have given out information under the wrong contexts or 
assumptions prior, possibly making the situation or understanding worse.  I'm 
afraid I may be guilty of the latter, and making things worse.

-- Bryan

P.S.  Sorry I haven't made any meetings.  It's either work or I'm already pooped 
from another meeting the night before (Corvette Club of America meets the 2nd 
Tuesday of the month all the way over in Gaithersburg).



----- Original Message ----
From: Bryan J Smith <b.j.smith at ieee.org>

From: Walt Smith <waltechmail at yahoo.com>
> The ASUS WL-520-GC has a WAN, 4-LANS and antenna.
> It's apparently a router, not a switch.

Okay, I didn't realize the Asus you were talking about prior was an embedded 
device.  Now I feel stupid.  I thought it as a notebook.  Or do you have both?  
(confused?)

A typical SOHO "Router" is 3 things ...
1.  Switch (Layer 2):  802.3 (Ethernet) LAN 4-port
2.  Bridge (Layer 2):  802.3 (Ethernet) LAN to 802.11 (Wireless) LAN
3.  Router (Layer 3):  802.3 (Ethernet) LAN to 802.3 (Ethernet) WAN

You're probably confused about #1 because there is _nothing_ to do in the 
firmware for the Asus.  The 4-port LAN switch is done 100% in hardware.  It only 

takes a '70s 8-bit 8051 core with a few Network Processing Elements (NPE) to do 
MAC switching.  In a nutshell, this 5 cent (literally, in silicone dollars), 10K 

or so gate logic set does what it takes a traditional Pentium Von Newman 
approach to do.

What the Asus is going to provide in firmware is #2 and #3.  The #2 should get 
some ASIC/NPE boosts as well, likely part of the 32 or 64-bit ARM core that is 
the ASIC of the WLAN itself.  Intersil (Harris Semiconductor) showed this off 
back in 2000 (I know some of the engineers who designed it) and it's pretty much 

the standard approach.

#3 will all be software.

> I'm not connecting the WAN.

So you're not using #3.

> I want to connect a desktop to the LAN and let the antenna go elsewhere.

Same subnet?  Or different subnet?
Same subnet should "just work," per #2, it's a 802.3 to 802.11 bridge.

#2 is also called an "Access Point" (AP).  Most SOHO Routers have very cheap and 

inexpensive ASICs in them.  More expensive, dedicated APs have better ASICs that 

can handle dozes of nodes with full AES WPA.

> The Asus seems to have found one station.  And it sticks.
> Refresh doesn't change anything.   This is the part I'm not
> sure about.  Need to prove the RF is working.

Define "found one station."

Your AP (#2) gives you an "infrastructure."  Every 802.11 node should associate 
with it.  From there, every station can talk to one another, as well as be 
bridged (via the AP) to the 802.3 network.

You should not be using "adhoc" or "peer-to-peer" mode of 802.11.

> By comparison, use of a linksys wifi card on a XP laptop has confused
> things.  For example, I can see about 10 systems.  Of those, I often
> get 4 or so "open" that have low signal strength, so they "come and go";
> they have different SSID names. However,
> they each have a different IP  at 192, but each has the same MAC
> number ( or physical number ).  This I do not understand.

Again, "infrastructure" mode should be the default and should "just work."  All 
nodes use the same SSID to _associate_ with.

Do _not_ setup anything other than the Asus AP to provide the SSID.  You may be 
accidentally setting up other nodes to be host-based APs, which is why they have 

different SSIDs.  Do _not_ setup anything on anything but the Asus.  
Infrastructure mode is designed to be easy and painless.

> Using XP software ( not linksys ), I also cannot tell which channel 
> each connect over.  The setup I believe is "auto".

Auto should work.

For the most part, you only need to start messing with channels when you have 
multiple APs in the building.  It's ideal to use different channels so there is 
less congestion with nearby APs.

Other devices should automatically find it, based on the SSID.  They scan the 
whole spectrum -- a band around 2.4GHz for 802.11/b/g and 5GHz for 802.11a -- 
with 802.11n being more of a software change, allowing multiple bands and other 
aggregations (finally standardizing on lots of vendor-specific approaches, like 
MIMO).

SIDE NOTE:  IEEE 802.11/b/g standards are officially 2, 11 and 22Mbps (yes, _22_ 

for g, official IEEE tested and designed standard -- there are vendor "boost" 
modes that have been documented since that allow up to 54Mbps -- but I've been 
involved with several people on 802.11 sub-committees 1999-2005).  IEEE 802.11a 
is officially 54Mbps, but shorter range because of the higher frequency (lower 
wavelength) for the same power (to FCC allowed levels).

> I wanted the channel numbers most used so I could set the Asus.  Setting the 
>ASUS 
>
> to one channel allowed it to find one signal.  Curiously enough,
> the XP laptop see's the ASUS as a signal: sig strength is max, it goes
> away when I disconnect the ASUS power, but again, the Physical Number
> of the ASUS seems to be the same.. UNLESS the physcial number is the
> number of my linksys card ?  I've been unable to find a Windows
> control-panel or other status to find the XP linksys mac number.

The IEEE assigned MAC address (actually, the IEEE assigns the first 3, the 
vendor number, with the last 3 being iterated by the vendor for the block) can 
be found in any NT-based Windows with the "ipconfig /all" command.

NOTE:  If you load 3rd party software in Windows, things can get really screwed 
up with drivers and Windows support.  The lack of many standard interfaces by 
Microsoft results in vendors doing a lot of things their way, including vendor 
software conflicting with one another, or even Microsoft additions/subsystems.

> To something more specific, if I get a channel to another wifi,
> I see the wifi addresses may be 192.168.1.x or 192.168.2.x.
> I assume that I can see the IP number of the foreign wifi.

You are seeing multiple networks because you have multiple SSIDs for multiple 
infrastructures and/or ad-hod peer-to-peer setups.  You want 1, single SSID for 
one, single infrastructure provided by the Asus AP.

If you are not familiar with 802.11 Wireless LAN, how it works (extremely 
different than 802.3 Ethernet LAN), all of the terminology and differences, it's 

very, very easy to change the configuration and set all sorts of modes that 
doesn't "just work."  Normally "infrastructure" mode -- other than defining any 
RC4 (WEP or WPA TKIP) or AES (WPA and required with WPA2) key -- "just works."

I'd recommend resetting your Asus Router device's firmware to factory defaults.  

But I assume you've flashed its firmware with a new image, custom jobbie?  I am 
just now waking up to this.  ;)


-- 
Bryan J  Smith             Professional, Technical Annoyance 
Linked Profile:           http://www.linkedin.com/in/bjsmith 
------------------------------------------------------------ 
"Now if you own an automatic ... sell it!
You are totally missing out on the coolest part of driving"
-- Johnny O'Connell





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