Is having too many WAPs in one area a bad thing?

I ran NetStumbler and noticed 21 different WAPs (houses and apartments)
in one area. Wow. Does having this many cause problems like inter-
ferences even with good/decent signals? I noticed most of them use
channel 6.

Thank you in advance.
--
"Be thine enemy an ant, see in him an elephant." --Turkish Proverb
/\___/\
/ /\ /\ \ Ant @ The Ant Farm: http://antfarm.ma.cx
| |o o| | Ant's Quality Foraged Links: http://aqfl.net (offline)
\ _ / Please remove ANT if replying by e-mail.
( )

(E-Mail Removed) wrote:
>I ran NetStumbler and noticed 21 different WAPs (houses and apartments)
>in one area. Wow. Does having this many cause problems like inter-
>ferences even with good/decent signals? I noticed most of them use
>channel 6.

It'll definitely cause problems on channel 6! I'd pick another
channel as far from those as I could get... Of course, the best thing
to do would be put together an ad-hoc frequency managment council, map
spacial coverage of each unit, and determine which units should be set
to which channels (and which units can be set to a lower output power
where applicable), but I imagine that'll never happen.

Wonder how many others are there with SSID broadcast turned off?

William wrote:
> (E-Mail Removed) wrote:
> >I ran NetStumbler and noticed 21 different WAPs (houses and apartments)
> >in one area. Wow. Does having this many cause problems like inter-
> >ferences even with good/decent signals? I noticed most of them use
> >channel 6.

> It'll definitely cause problems on channel 6! I'd pick another
> channel as far from those as I could get... Of course, the best thing
> to do would be put together an ad-hoc frequency managment council, map
> spacial coverage of each unit, and determine which units should be set
> to which channels (and which units can be set to a lower output power
> where applicable), but I imagine that'll never happen.

It will definitely won't happen with that many WAPs and how many
people live here. No way. I don't even know my neighbors.


> Wonder how many others are there with SSID broadcast turned off?

I will try channel 1. Isn't NetStubmler supposed to pick up both off and
on?
--
"Be thine enemy an ant, see in him an elephant." --Turkish Proverb
/\___/\
/ /\ /\ \ Ant @ The Ant Farm: http://antfarm.ma.cx
| |o o| | Ant's Quality Foraged Links: http://aqfl.net (offline)
\ _ / Please remove ANT if replying by e-mail.
( )

I agree.
Would never of thought that congestion would be an issue.
Maybe there is a need for the new aband frequencies after all.
What channels would the experts suggest trying after channel 1 ?
(E-Mail Removed) wrote:
> William wrote:
> > (E-Mail Removed) wrote:
> > >I ran NetStumbler and noticed 21 different WAPs (houses and
apartments)
> > >in one area. Wow. Does having this many cause problems like inter-
> > >ferences even with good/decent signals? I noticed most of them use

> > >channel 6.
>
> > It'll definitely cause problems on channel 6! I'd pick another
> > channel as far from those as I could get... Of course, the best
thing
> > to do would be put together an ad-hoc frequency managment council,
map
> > spacial coverage of each unit, and determine which units should be
set
> > to which channels (and which units can be set to a lower output
power
> > where applicable), but I imagine that'll never happen.
>
> It will definitely won't happen with that many WAPs and how many
> people live here. No way. I don't even know my neighbors.
>
>
> > Wonder how many others are there with SSID broadcast turned off?
>
> I will try channel 1. Isn't NetStubmler supposed to pick up both off
and
> on?
> --
> "Be thine enemy an ant, see in him an elephant." --Turkish Proverb
> /\___/\
> / /\ /\ \ Ant @ The Ant Farm:
http://antfarm.ma.cx
> | |o o| | Ant's Quality Foraged Links: http://aqfl.net
(offline)
> \ _ / Please remove ANT if replying by
e-mail.
> ( )

On Sun, 10 Apr 2005 16:29:35 -0500, (E-Mail Removed) wrote:

>I ran NetStumbler and noticed 21 different WAPs (houses and apartments)
>in one area. Wow. Does having this many cause problems like inter-
>ferences even with good/decent signals? I noticed most of them use
>channel 6.

Most wireless routers are delivered on channel 6. The alternative
non-overlapping channel options are 1, 6, and 11. You can get away
with channels in between, but you run the risk of getting interference
from both 1/6 and 6/11.

Netstumbler only shows the wireless access points and peer to peer
networks. There are also client radios that are not being shown.
Assuming at least 1 client per access point, you now have about 40
radios in the nighborhood. Probably more. Incidentally, best is from
the roof of a downtown San Jose office building showing about 200
visible access points.

The odd part is that you could easily have 100 access points in the
area, and not have any problems with interference, if they are not
active. Most of the access points you're seeing are only active when
the residents are home and operational. When traffic is minimal, so
is interference. The ocassional beacons do little damage.

What you'll see is that one or two active access points will slow you
down noticeably when running at maximum speed. The access point uses
the signal to noise ratio (not the signal strength) to determine the
maximum connection speed. If the noise level increases, as it would
if there were other users on the channel, the access point will slow
down. Some firmware takes a full minute to recover. However, these
slowdowns will only happen when the neighbors are using their systems
and moving traffic.

The exceptions are the wireless TIVO and music systems. Also, some
(not all) point to point wireless transparent bridges. These are
belching traffic almost continuously. You won't see the bridges with
Netstumbler.

If it's any consolation, your system will generate as much
interference as it receives. If you can see 21 neighbors, they can
also see your transmissions. Therefore, you too can be part of the
problem. (The surest sign of success is pollution, and Wi-Fi is
certainly successful).

The easiest solution is to locate your in-house network away from
windows and areas with lots of neighborhood exposure. Directional
antennas and reflectors also help. Try to select a least used
channel. Beyond that, you can probably expect some interference if
you see that many access points.


--
Jeff Liebermann (E-Mail Removed)
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 AE6KS 831-336-2558

(E-Mail Removed) wrote:
> I agree.
> Would never of thought that congestion would be an issue.
> Maybe there is a need for the new aband frequencies after all.
> What channels would the experts suggest trying after channel 1 ?
> (E-Mail Removed) wrote:

11. There is no band overlap between 1 and 6, or 6 and 11.
--
Cheers, Bob

Bob Willard <(E-Mail Removed)> wrote:
> (E-Mail Removed) wrote:
> > I agree.
> > Would never of thought that congestion would be an issue.
> > Maybe there is a need for the new aband frequencies after all.
> > What channels would the experts suggest trying after channel 1 ?
> > (E-Mail Removed) wrote:

> 11. There is no band overlap between 1 and 6, or 6 and 11.

I will try that. There are five existing WAPs using channel 11. Only one
was using channel 1. I tried channel 1 for the last two days as the
second AP, but it doesn't seem to make much differences. Will channel
11 be that much better?
--
"Be thine enemy an ant, see in him an elephant." --Turkish Proverb
/\___/\
/ /\ /\ \ Ant @ The Ant Farm: http://antfarm.ma.cx
| |o o| | Ant's Quality Foraged Links: http://aqfl.net (offline)
\ _ / Please remove ANT if replying by e-mail.
( )

Jeff Liebermann <(E-Mail Removed)> wrote:
> On Sun, 10 Apr 2005 16:29:35 -0500, (E-Mail Removed) wrote:

> >I ran NetStumbler and noticed 21 different WAPs (houses and apartments)
> >in one area. Wow. Does having this many cause problems like inter-
> >ferences even with good/decent signals? I noticed most of them use
> >channel 6.

> Most wireless routers are delivered on channel 6. The alternative
> non-overlapping channel options are 1, 6, and 11. You can get away
> with channels in between, but you run the risk of getting interference
> from both 1/6 and 6/11.

> Netstumbler only shows the wireless access points and peer to peer
> networks. There are also client radios that are not being shown.
> Assuming at least 1 client per access point, you now have about 40
> radios in the nighborhood. Probably more. Incidentally, best is from
> the roof of a downtown San Jose office building showing about 200
> visible access points.

> The odd part is that you could easily have 100 access points in the
> area, and not have any problems with interference, if they are not
> active. Most of the access points you're seeing are only active when
> the residents are home and operational. When traffic is minimal, so
> is interference. The ocassional beacons do little damage.

> What you'll see is that one or two active access points will slow you
> down noticeably when running at maximum speed. The access point uses
> the signal to noise ratio (not the signal strength) to determine the
> maximum connection speed. If the noise level increases, as it would
> if there were other users on the channel, the access point will slow
> down. Some firmware takes a full minute to recover. However, these
> slowdowns will only happen when the neighbors are using their systems
> and moving traffic.

> The exceptions are the wireless TIVO and music systems. Also, some
> (not all) point to point wireless transparent bridges. These are
> belching traffic almost continuously. You won't see the bridges with
> Netstumbler.

> If it's any consolation, your system will generate as much
> interference as it receives. If you can see 21 neighbors, they can
> also see your transmissions. Therefore, you too can be part of the
> problem. (The surest sign of success is pollution, and Wi-Fi is
> certainly successful).

> The easiest solution is to locate your in-house network away from
> windows and areas with lots of neighborhood exposure. Directional
> antennas and reflectors also help. Try to select a least used
> channel. Beyond that, you can probably expect some interference if
> you see that many access points.

Interesting, Yeah, wireless is pretty frustrating. Even my own hearing
aid can hear interference if I am close enough to a WAP! It's like being
close to a digital cellular phone. Analog cellphondes didn't have this
problem.

Directional antennaes and reflectors will be hard to set up in this
home since it is not mine and lack of space due to tiny room size.
Isn't Hi-Gain USB Wireless-G Adapter (Model: HWU54D)'s Hi-Gain Antenna
( photographs on http://www.hawkingtech.com/prodSpec.php?ProdID=208 )
sufficient enough? It doesn't seem to help during bad times.

I am currently trying channel 1, but it didn't seem to help much last
night when I had connection problems. I don't think switching to
channel 11 that someone suggested will improve. Beside it already has
five existing WAPs on it. Channel 1 had one before I joined it. Do
you think channel 11 will help?
--
"Be thine enemy an ant, see in him an elephant." --Turkish Proverb
/\___/\
/ /\ /\ \ Ant @ The Ant Farm: http://antfarm.ma.cx
| |o o| | Ant's Quality Foraged Links: http://aqfl.net (offline)
\ _ / Please remove ANT if replying by e-mail.
( )

(E-Mail Removed) wrote:
> Bob Willard <(E-Mail Removed)> wrote:
>
>>(E-Mail Removed) wrote:
>>
>>>I agree.
>>>Would never of thought that congestion would be an issue.
>>>Maybe there is a need for the new aband frequencies after all.
>>>What channels would the experts suggest trying after channel 1 ?
>>>(E-Mail Removed) wrote:
>
>
>>11. There is no band overlap between 1 and 6, or 6 and 11.
>
>
> I will try that. There are five existing WAPs using channel 11. Only one
> was using channel 1. I tried channel 1 for the last two days as the
> second AP, but it doesn't seem to make much differences. Will channel
> 11 be that much better?

Unpredictable. Just try it.
--
Cheers, Bob

Too much of anything is bad.

Barry