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Re: two AP's with same SSID for coverage
On 26/01/2009 00:05, Jeff Liebermann wrote:
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<http://www.theruckusroom.net/2008/12/pest-control-80211ns-dirty-little-secret.html
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In your "testing" have you noticed any impact if a BT device is
operational? I don't have any 11n AP's to verify this statement on the
Intel site.
" Another mechanism, designed to protect Bluetooth devices is a means of
signaling that the wireless network should not use the wider (40 MHz)
channel width. An 802.11n device that knows of potential interference
with Bluetooth (e.g. a laptop with both 11n and BT) can force its BSS
and neighboring BSSís to stop transmitting 40 MHz. This reduces any
potential impact on these devices to the same level as existing
802.11b/g devices."
<http://www.intel.com/standards/case/case_802_11.htm



Re: two AP's with same SSID for coverage
LR wrote:
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I have a BT AP plugged into the router part of my b/g regular wap/router
(Pretty cool product, anycom BT lan AP, sold elsewhere in the world but not
the us
http://www.anycom.com/products/bluetooth_it_pc_accessoires/edr_ap_lan_access_point/?id=102&partno=CC3053 ,
One pda does BT only-no wifi, and works with bt dongles), right next to the
wap/router that does n with wide channels, and notice no problems....

may only refer to a laptop that does both, sure doesn't seem to cause a prob
with ap's, and devices that do one thing instead of both.....



Re: two AP's with same SSID for coverage
On 26/01/2009 17:44, Peter Pan wrote:
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http://www.anycom.com/products/bluetooth_it_pc_accessoires/edr_ap_lan_access_point/?id=102&partno=CC3053 ,
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I am wondering if this is due to not having a definitive 11n standard as
yet and some devices will conform to what the Intel website says and
others won't.
If we take your n router:-
<http://ui.linksys.com/files/WRT160N/v2/2.0.00/manual.htm
you cannot set the "40MHz Channel" nor pick the "Wide Channel" however
if you look at the V1 you can.
<http://ui.linksys.com/files/WRT160N/v1/1.01.21/Manual.htm
This may be due to a change in the draft std. but as I don't have a copy
I can't check.






Re: two AP's with same SSID for coverage
LR wrote:
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sure you can......
just out of curiosity, why don't you use the actual linksys site (now
linksysbycicsco, I have no clue what the above are since I only get a screen
display)
select  v1 or v2
http://downloads.linksysbycisco.com/downloads/WRT160N_ug.pdf
Radio Band For best performance in a network, keep the
default, Wide - 40MHz Channel. For Wireless-G and
Wireless-B networking only, select Standard - 20MHz




Channel.



Re: two AP's with same SSID for coverage
On 27/01/2009 03:05, Peter Pan wrote:
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The links I provided are interactive so you can change the settings on
the website, which is much easier than downloading the pdf. file.

Re: two AP's with same SSID for coverage
LR wrote:
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okay, so it doesn't have the same defaults as the manual specifies, and
doesn't work the same way as an actual wap/router.....

from what you said above "you cannot set the "40MHz Channel" nor pick the
"Wide Channel" yes you can with a real device, it's in the acual manual, and
in v2 it's the default, so it seems like you just can't set it in the online
simulation you pointed to, but you can on the real device, and the real
manual tells you how/why/etc.... fraid I don't see why I would want to waste
my time with something innacurate?



Re: two AP's with same SSID for coverage

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Sorry, but this was not "testing".  Testing is when I record results
and follow a reproduceable test procedure.  Screwing around is when I
tinker with the hardware to see what I can break.  This was screwing
around.  In addition, the owner of the laptop was getting a bit
anxious as I was tweaking settings and (shudder) using the bash shell
prompt on his Mac.  Everyone knows that the command line is the sure
way to make a mess.

However, one of my customers just took delivery on a Dell Precision
M4400 laptop with an Intel 5300 a/g/n 3x3 MIMO card.  The laptop does
NOT have built in BlueGoof but I can simulate the interference with my
cell phone playing MP3's to my BT 2.0 stereo headset.  Time
permitting, I'll give it a try with a WRT350N and see what breaks.

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Some of the new hardware uses a common card for Wi-Fi and BT. Only one
is active at a time.  The common hardware timeshares between Wi-Fi and
BT resulting in dismal throughput for both, but no interference.  I
played with an early version of one of these (forgot the vendor).  It
worked, as expected was slow, and did not create any disconnects or
hangups, which is really the objective of this system.

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Nice feature.  Translation:  When there's so much crap flying through
the air, that high speed data is essentially impossible, the wireless
access point will give up trying and run at slower speeds.  

As I understand the spec (which I haven't read), anything that causes
excessive retransmissions and retries in the 40Mhz mode, will cause it
to slow down to the 20Mhz mode.  It doesn't have to be BT.  It could
be a microwave oven.  My guess(tm) is that this is to insure that flow
control works, where the AP can hear a/b/g broadcasts in 20MHz mode,
that are not detectable while in 40MHz mode.  The fear of creating
unrecoverable interference in the 40MHz mode is what probably inspired
this feature.


--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558            jeffl@comix.santa-cruz.ca.us
# http://802.11junk.com jeffl@cruzio.com
# http://www.LearnByDestroying.com               AE6KS

Re: two AP's with same SSID for coverage
On 26/01/2009 00:05, Jeff Liebermann wrote:
?  More:
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<http://www.theruckusroom.net/2008/12/pest-control-80211ns-dirty-little-secret.html


My first thought on seeing the photo was of the replicators from
Stargate running around the floor.

Ruckus and Cisco do seem like a bit of a squabble.
<http://www.techworld.com/mobility/news/index.cfm?newsID=109462&pagtype=samechan
Cisco's "beamforming"
<http://www.cisco.com/en/US/prod/collateral/wireless/ps5678/ps10092/white_paper_c11-516389.html>

Re: two AP's with same SSID for coverage

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Moving from 802.11g to 802.11n (2.4GHz) is already a "replace
everything" situation, all we're talking about is what gear you put in.

Re: two AP's with same SSID for coverage
On Mon, 26 Jan 2009 07:45:07 -0800, DevilsPGD

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Not really.

If I replace the router with a spatial diversity type 2.4GHz 802.11n
router, all the older 802.11g clients continue to work.

If I replace the router with a spatial beam forming 2.4GHz 802.11n
router, all the older 802.11g clients continue to work.

If I replace the 2.4GHz router with a 5.8GHz router, nothing works
unless I also replace all the client radios.

If I replace the 2.4GHz router with a dual band 802.11n router, the
older 802.11g radios continue to work, but I have to reconfigure
literally every dual band client radio to default to 5.8GHz.  Those
with single band 2.4GHz client radios continue to work, but derive no
benefits.

Incidentally, I do have two client with dual band wireless routers.
I've lost money on both due to the numerous stupid problems I've had
to fix or work around.  Most involve connection managers and client
radio drivers that are clumsy, sloppy, or inept at dealing with
multiple bands.  

Incidentally, in my WRT350N, there's no way to disable the 2.4GHz band
leaving only 5.8GHz operational:
<http://ui.linksys.com/files/WRT350N/1.03.2/Wireless_Basic.htm
Also note that the SSID applies to both bands.  Seen any 5.8Ghz access
points or wireless routers lately?



--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558            jeffl@comix.santa-cruz.ca.us
# http://802.11junk.com jeffl@cruzio.com
# http://www.LearnByDestroying.com               AE6KS

Re: two AP's with same SSID for coverage
On 27/01/2009 03:04, Jeff Liebermann wrote:

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Your confusing me again.
I thought the WRT350N was only a 2.4GHz band router.
I thought it was when they introduced the WRT600N they started the dual
band router.
<http://ui.linksys.com/files/WRT600N/1.01.35/BasicWirelessSettings.htm

Re: two AP's with same SSID for coverage

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Argh.  You're right.   My appologies.  The WRT600N does allow
independent control of each band and independent SSID's.  I'm not sure
why I thought the WRT350N was a dual band.

Full disclosure:  I've been fighting some rather nasty kidney stone
problems erratically since Thanksgiving and full time since New Years.
Most of the time, I'm mildly drugged, which seems to have an effect on
my judgement and memory.  I've reduced the frequency of my postings,
but apparently that's not sufficient to insure accuracy.  I think I'll
abstain from any more postings that require much thinking until I'm
off the pain killers.

--
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

Re: two AP's with same SSID for coverage
On 27/01/2009 20:54, Jeff Liebermann wrote:

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You have my sympathy. My mother suffered from kidney stones for years
before Lithotripsy was introduced.

Re: two AP's with same SSID for coverage

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Reminds me of a scene in "Taxi" where Christopher Lloyd's character
(Ignatzki?) has to renew his driver's permit, and the clerk querying his
qualifications asks "Drug addiction or mental illness?" and he replies
"Hmm, that's a difficult choice."

Get better soon, J.L.  Anyway, even stoned you make more sense than most
people on Usenet.
--
W. Oates

Re: two AP's with same SSID for coverage
~ Seen any 5.8Ghz access points or wireless routers lately?

We sold half a million or so of them last year.  It's kinda nice
to have 20 non-overlapping 20MHz channels, and no Bluetooth/
legacy 802.11b/microwave interference, if you're serious about
delivering connectivity over non-regulated wireless.

Of course, these are most all in good sized enterprises, not in
your house.

Re: two AP's with same SSID for coverage
wrote:

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I checked the Cisco web site for an 802.11a only access point and
couldn't find one.  
<http://www.cisco.com/en/US/products/hw/wireless/index.html#wireless-for-access_points>
Most everything seems to be "ag" suffix which I presume means it will
do both bands, or no suffix, which usually means "g" only.  I guess
one could order an Aironet 1200 with only an 802.11a PcCard, instead
of the usual 802.11g PcCard, but that would make it a special order.

What's the Cisco model numbers or series?  I'm curious.

Yep.  The lack of interference is a good thing.  One of my friends
recently replaced his 2.4GHz only wireless router with a dual band
version.  I don't recall the model numbers.  Range and thruput to his
laptop was dramatically better on 5.8GHz than on 2.4GHz.  My guess(tm)
is that this was due to massive interference from numerous 2.4GHz
networks in the area, possibly compounded by a local messh wireless
system.

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Ummm.... Linksys is Cisco's consumer product line.  No 802.11a only
access points (that I know about).  Other than the high price,
complexity, and management overhead, I don't have anything against
using enterprise solutions in the home.


--
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

Re: two AP's with same SSID for coverage
~ >~ Seen any 5.8Ghz access points or wireless routers lately?

~ >We sold half a million or so of them last year.  It's kinda nice
~ >to have 20 non-overlapping 20MHz channels, and no Bluetooth/
~ >legacy 802.11b/microwave interference, if you're serious about
~ >delivering connectivity over non-regulated wireless.

~ I checked the Cisco web site for an 802.11a only access point and
~ couldn't find one.  
~
<http://www.cisco.com/en/US/products/hw/wireless/index.html#wireless-for-access_points>
~ Most everything seems to be "ag" suffix which I presume means it will
~ do both bands, or no suffix, which usually means "g" only.  I guess
~ one could order an Aironet 1200 with only an 802.11a PcCard, instead
~ of the usual 802.11g PcCard, but that would make it a special order.
~
~ What's the Cisco model numbers or series?  I'm curious.

Ah, you meant a 5GHz *only* AP.  Yep, we don't make those as such
(other than I suppose the special case where one would get, as you
mention, a 1200 or 1240 series AP and install only the 5GHz radio.)

But I would say that, in our medium-large enterprise installations,
at least 80% of our installed APs are dual-band (except for in those
countries that don't allow 5GHz wifi.)

~ Yep.  The lack of interference is a good thing.  One of my friends
~ recently replaced his 2.4GHz only wireless router with a dual band
~ version.  I don't recall the model numbers.  Range and thruput to his
~ laptop was dramatically better on 5.8GHz than on 2.4GHz.  My guess(tm)
~ is that this was due to massive interference from numerous 2.4GHz
~ networks in the area, possibly compounded by a local messh wireless
~ system.

Probably a good guess any more.

~ >Of course, these are most all in good sized enterprises, not in
~ >your house.

~ Ummm.... Linksys is Cisco's consumer product line.  No 802.11a only
~ access points (that I know about).  Other than the high price,
~ complexity, and management overhead, I don't have anything against
~ using enterprise solutions in the home.

:)

Re: two AP's with same SSID for coverage
wrote:

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Sorry (again), my fault.  Looking at my original comment, I forgot to
include the word "only".  Yet another screwup.

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Also 4.9GHz for public safety.  The fairly small incremental cost of
adding the 2nd wireless PcCard is nominal compared to the cost of the
access point.  However, I wonder how many of those medium-large
enterprise installations actually use 5.8GHz?  WiFi Hopper and various
sniffers (Kismet and Kismet-Newcore) will display and filter by 802.11
mutation.  I've sniffed with these around industrial districts and
haven't really found much traffic.  Plenty of point to point links,
some SSID broadcasts, but very little client traffic moving.  The AP's
may be out there, but they don't seem to be using 5.8GHz.

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Guesswork is my trademark.  

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Back around 2000-2002, after the dot com bust, many companies gave
their layed off employees a severance bonus in the form of surplus
computing equipment.  Convincing a home users that a RAID 5 redundant
everything server, some giant Cisco router, a 48 port ethernet
switches, and such were not suitable for the average home user, was
ummm.... awkward.  Yell louder.... I can't hear you over the fan
noise.  Why is it 120F in here?  Why is everything so big?  Anyway, I
had lots of experience deploying enterprise grade hardware in several
home environments.  The trick was to get paid before the electric bill
arrived.

Favorite enterprise hardware questions from the home user... where is
the on-off switch?  Why is it on the rear panel where I can't get to
it?  What do you mean it never gets turned off?




--
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

Re: two AP's with same SSID for coverage

~ >But I would say that, in our medium-large enterprise installations,
~ >at least 80% of our installed APs are dual-band (except for in those
~ >countries that don't allow 5GHz wifi.)
~
~ Also 4.9GHz for public safety.  The fairly small incremental cost of
~ adding the 2nd wireless PcCard is nominal compared to the cost of the
~ access point.  However, I wonder how many of those medium-large
~ enterprise installations actually use 5.8GHz?  WiFi Hopper and various
~ sniffers (Kismet and Kismet-Newcore) will display and filter by 802.11
~ mutation.  I've sniffed with these around industrial districts and
~ haven't really found much traffic.  Plenty of point to point links,
~ some SSID broadcasts, but very little client traffic moving.  The AP's
~ may be out there, but they don't seem to be using 5.8GHz.

5GHz has definitely reached critical mass in the enterprise.  It's the
band of choice for 802.11 phones (our 7921/7925s).  And enterprise grade
laptops pretty much all now come with dual band NICs.

We are pushing 5GHz especially for 802.11n.  For obvious reasons,
40MHz wide channels in 2.4GHz make zero sense in any dense deployment.
While the relatively wide open spaces of say the UNII-2 Extended
band would accommodate a few such channels quite nicely.

~ Back around 2000-2002, after the dot com bust, many companies gave
~ their layed off employees a severance bonus in the form of surplus
~ computing equipment.  Convincing a home users that a RAID 5 redundant
~ everything server, some giant Cisco router, a 48 port ethernet
~ switches, and such were not suitable for the average home user, was
~ ummm.... awkward.  Yell louder.... I can't hear you over the fan
~ noise.  Why is it 120F in here?  Why is everything so big?  Anyway, I
~ had lots of experience deploying enterprise grade hardware in several
~ home environments.  The trick was to get paid before the electric bill
~ arrived.

True that.  Although our APs aren't so bad.  I have an 871W and an AP1131
(in addition to my trusty WAP54G) at home, and if they were visually or
audibly unacceptable in any way, I am confident that my wife, who is
hypervigilant in those regards, would have called them out.

~ Favorite enterprise hardware questions from the home user... where is
~ the on-off switch?  Why is it on the rear panel where I can't get to
~ it?  What do you mean it never gets turned off?

Why, our APs' on/off switch is the software settings on the PoE switch, of
course ... what could be simpler?


Re: two AP's with same SSID for coverage
wrote:

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5AM, can't sleep, mildly drugged... let's see if the brain is still
functional.

Yep, the logic is compelling.  I note that the user has the choice of
"preferred" band and mode.  However, the default seems to be which
ever band produces the strongest signal:
<http://www.cisco.com/en/US/prod/collateral/voicesw/ps6788/phones/ps379/product_data_sheet0900aecd805e315d.html>
  Support mode    
    - 802.11a
    - 802.11b/g
    - Autosensing, 802.11b/g preferred over 802.11a
    - Autosensing, 802.11a preferred over 802.11b/g
    - Received signal strength indicator (RSSI) (default)

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I don't recall the exact terms of the compromise worked out between
the parties involved.  Both the 871w and AP1131 are relatively small
boxes, with minimal wiring, no fan, little heat, and are fairly easy
to hide.  Unless your network wiring looks like this:
<http://802.11junk.com/jeffl/pics/drivel/slides/mess01.html
I don't think there would be any complaints.

However, the "enterprise quality" equipment I was trying to install in
a home environment came from a dot com that owned their own servers
and rented rack space at a server farm.  I don't recall the model
numbers, but suffice to say that the hardware was big, ugly, noisy,
hot, and expensive to operate.  While I'm sure this was not the intent
of the original statement suggesting the use of "enterprise quality"
equipment in the home, it does offer and extreme example.

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I left out one question.... Why do I need a computer just to turn this
thing on and off?  The point is that the typical home user has
different expectations on how to install, operate, and configure the
equipment.  I ran into this problem trying to configure a 7690 IP
phone.  Without a TFTP server, it was futile.  There are some rather
fundamental differences between a locally configured IP phone, and one
that requires an IT department to manage the downloadable
configuration from a permanent server.  There's also no (easy) way to
save the settings.

Then, I noticed that there was no backlighting on the 7690 LCD
display.  That makes sense in an "enterprise" environment, where the
lights are never turned off during working hours.  However, at home,
trying to dial a number at night requires a flashlight.  I also have a
Linksys/Sipura SPA921 with exactly the same issues.  

Sure, bring the "enterprise hardware" home and it can be made work.
Just be prepared for some oddities and ummm.... inconveniences.  Ask
your wife what she thinks of an IP telephone that doesn't light up in
the dark.


--
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

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