Re: Advice needed on Wireless Network Card (amongst other things)

On Thu, 14 Feb 2008 20:46:52 -0500, armando
<armando.34suma@no-mx.wirelessforums.org> wrote:

>What I am most concerned about is reaching the 54mbps, or as close as
>possible. And to do this I need better reception/signal than what I
>have. This only has to go through 1 wall...about 15-20 metres..but it
>must have excellent signal...

It won't happen. In order to achieve and maintain a 54Mbits/sec
association (connection), you must have a very good SNR (signal to
noise ratio) in both directions. (Note: The connection speed can be
different in each direction). That difficult to achieve beyond a
range of about 15 meters and totally impossible going through a wall
due to additional attenuation and reflections. It's also not just the
"card" that has to have an excellent signal. So does the access
points (or wireless router).

See the FAQ at:
<http://wireless.wikia.com/wiki/Wi-Fi#Performance_and_Speed>
in the table of speeds and estimated ranges. At 54Mbits/sec, it
suggests 90ft (27.4 meters) is about the limit. The table came from
the Intel Wireless Hotspot Deployment Guide, which methinks is a bit
optimistic. 27 meters might be possible under absolutely ideal
conditions. Certainly not indoors and going through a wall. What
you'll probably see is the speed varying up and down as traffic
varies, as reflections come and go, and as interference apears.

If you can borrow a wireless laptop, try maintaining a 54Mbit/sec
connection through the wall in question. Use Netstumbler or Kismet
for monitoring the connection speed. Do it while streaming some
videos or copying large files.

Sorry, no recommendation.

--
# 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

Jeff Liebermann wrote:
> It won't happen. In order to achieve and maintain a 54Mbits/sec
> association (connection), you must have a very good SNR (signal to
> noise ratio) in both directions. (Note: The connection speed can be
> different in each direction). That difficult to achieve beyond a
> range of about 15 meters and totally impossible going through a wall
> due to additional attenuation and reflections. It's also not just the
> "card" that has to have an excellent signal. So does the access
> points (or wireless router).

Someone was telling me of a WISP that's going offer 20 Mbps
to locations up to eight miles away.

Of course they have a disclaimer "your speed may vary with the
distance from the tower". Currently they are offering 10 Mbps out
to six miles, but a quick plot shows 90.1 to 90.5 reliability. I
wonder how long they can keep customers happy with an annual
daily average of one to two hours downtime. People tell me they
are actually only getting 6 to 8 Mbps.

DTC <me@nothingtoseehere.zzx> hath wroth:

>Someone was telling me of a WISP that's going offer 20 Mbps
>to locations up to eight miles away.

Probably WiMax.
<http://en.wikipedia.org/wiki/Wimax>
(Note the comparison with Wi-Fi section)

"A commonly-held misconception is that WiMAX will deliver
70 Mbit/s over 50 kilometers. In reality, WiMAX can do one
or the other — operating over maximum range (50 km) increases
bit error rate and thus must use a lower bitrate. Lowering
the range allows a device to operate at higher bitrates."

>Of course they have a disclaimer "your speed may vary with the
>distance from the tower". Currently they are offering 10 Mbps out
>to six miles, but a quick plot shows 90.1 to 90.5 reliability. I
>wonder how long they can keep customers happy with an annual
>daily average of one to two hours downtime. People tell me they
>are actually only getting 6 to 8 Mbps.

Easy. The same way the Microsoft "educated" their customers to accept
erratic crashes, chronic security problems, lousy uptime, and sloth.
The customers that buy Microsoft products, and subscribe to wireless
internet probably have not experienced reliable internet. They also
may be coming from a worse situation, such as a proprietary OS or
satellite broadband, where Microsoft and WiMax would constitute a
major improvement.

Also, it you clearly advise the customer (i.e. shove it in their face)
that the system might be affected by congestion, terrorists, weather,
and outsourced sysadmin screwups, then customers are more likely to
accept such levels of service. As an added bonus, WiMax can be
portable, which is difficult with cable or DSL.

90% reliability is 8dB SNR which yields about 875 hours of downtime
per year or about 2.5 hrs downtime per day. Yeah, that sucks, but
it's still better than dialup and satellite. If you can't get wired
broadband, then you take what you can get.

Range, speed, or reliability. Pick any two.

--
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

Jeff Liebermann wrote:
> DTC <me@nothingtoseehere.zzx> hath wroth:
>
>> Someone was telling me of a WISP that's going offer 20 Mbps
>> to locations up to eight miles away.
>
> Probably WiMax.

Nope...I seem them on my spectrum analyzer on umm..channel 58 I
think it was. They just plain old 802.11a.

> They also may be coming from a worse situation

22K dialup...Yahoo and CNN take like 3 minutes to load a page.

> Range, speed, or reliability. Pick any two.

I'm offering two outta three...5 Meg user end point speeds,
30 dB plus fade margin and everyone within one mile of my tower.

On Fri, 15 Feb 2008 15:09:04 -0600, DTC <me@nothingtoseehere.zzx>
wrote:

>Jeff Liebermann wrote:
>> DTC <me@nothingtoseehere.zzx> hath wroth:
>>
>>> Someone was telling me of a WISP that's going offer 20 Mbps
>>> to locations up to eight miles away.
>>
>> Probably WiMax.
>
>Nope...I seem them on my spectrum analyzer on umm..channel 58 I
>think it was. They just plain old 802.11a.

Chuckle. Broadcast Ch 58 = 734-740 Mhz, which is part of the
spectrum the FCC is currently auctioning to the highest bidder. Unless
you mean cable Ch 58 = 427MHz, which is probably amateur TV.

>> They also may be coming from a worse situation
>
>22K dialup...Yahoo and CNN take like 3 minutes to load a page.

Ummm... 14.4kbits/sec on my cell phone. The only charge is for
minutes and no broadband contract required. However, all it's good
for is looking up phone numbers or Googling.

>> Range, speed, or reliability. Pick any two.
>
>I'm offering two outta three...5 Meg user end point speeds,
>30 dB plus fade margin and everyone within one mile of my tower.

Well, that will work. You should be able to handle exactly one file
sharing user. No problem with link reliability, but I wonder about
your potential user base. Whatcha gonna do when you get a midnight
phone call asking "is the internet down"? It's probably something
dumb, but do your really want to deal with it for free?


--
# 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

On Fri, 15 Feb 2008 16:08:13 -0800, Jeff Liebermann
<jeffl@comix.santa-cruz.ca.us> wrote in
<4t9cr3l4sodt24bjn0b2peehcoga547ar3@4ax.com>:

>Ummm... 14.4kbits/sec on my cell phone. The only charge is for
>minutes and no broadband contract required. However, all it's good
>for is looking up phone numbers or Googling.

Not any of the major carriers:
* Actual deployed speeds are much less than theoretical maximum
* Actual speeds drop further with tower load and range
* Verizon and Sprint are reportedly EV-DO Rev A, not Rev B.
Current typical real world burst speeds are a bit over 1 Mbps.

--
Best regards, FAQ for Wireless Internet: <http://Wireless.wikia.com>
John Navas FAQ for Wi-Fi: <http://wireless.wikia.com/wiki/Wi-Fi>
Wi-Fi How To: <http://wireless.wikia.com/wiki/Wi-Fi_HowTo>
Fixes to Wi-Fi Problems: <http://wireless.wikia.com/wiki/Wi-Fi_Fixes>

Jeff Liebermann wrote:
>> Nope...I seem them on my spectrum analyzer on umm..channel 58 I
>> think it was. They just plain old 802.11a.
>
> Chuckle. Broadcast Ch 58 = 734-740 Mhz, which is part of the
> spectrum the FCC is currently auctioning to the highest bidder. Unless
> you mean cable Ch 58 = 427MHz, which is probably amateur TV.

Sorry, it was channel 56 at 5.260 GHz.

>> I'm offering two outta three...5 Meg user end point speeds,
>> 30 dB plus fade margin and everyone within one mile of my tower.
>
> Well, that will work. You should be able to handle exactly one file
> sharing user. No problem with link reliability, but I wonder about
> your potential user base. Whatcha gonna do when you get a midnight
> phone call asking "is the internet down"? It's probably something
> dumb, but do your really want to deal with it for free?

File sharing is blocked and network is load managed...and $90 a month
ain't too free.

DTC <me@nothingtoseehere.zzx> hath wroth:

>Sorry, it was channel 56 at 5.260 GHz.

Oh, that channel. We have two local WISP's that are using 5.6GHz for
internet access. One is fairly smart about locating his towers so
that it doesn't hear the entire planet. The other is learning that
lesson in expensive stages.

We've also tried coordination, with some success:
<http://www.wbanc.com>
Not much activity lately.

The biggest local headaches are point to point 5.2/5.7 links that
belch RF all the time, even when no data is being passed (i.e. Western
Mux, Proxim). Most use highly directional antennas, but if you're
unlucky enough to be along their line of sight, the interference is
quite horrible. The State of Calif, cellular backhauls, and railroads
have been quite cooperative on reducing power, moving antennas, and
juggling channels. The Feds, military, and clueless corporations,
have not been as cooperative. Note that if a frequency hopper and a
direct sequence radio mutually interfere, the frequenyc hopper will
get some thruput, while the direct sequence radio will stop dead.

>>> I'm offering two outta three...5 Meg user end point speeds,
>>> 30 dB plus fade margin and everyone within one mile of my tower.
>>
>> Well, that will work. You should be able to handle exactly one file
>> sharing user. No problem with link reliability, but I wonder about
>> your potential user base. Whatcha gonna do when you get a midnight
>> phone call asking "is the internet down"? It's probably something
>> dumb, but do your really want to deal with it for free?

>File sharing is blocked and network is load managed...and $90 a month
>ain't too free.

No file sharing? That's going to be fun to enforce. One local WISP
does that with a rather high percentage of false positives. I'm told
that Cisco NBAR (Network Based Application Recognition) works, but I
have no experience.

Incidentally, it's not just the kids that do the file sharing. I've
been rather suprised to see who is really into file sharing.

I'm not sure $90/month will cover your time to answer dumb questions.
I find that 10% of my customers burn 90% of my "spare" time with dumb
questions. On my (almost) free neighborhood WLAN, I got an email from
a neighbor informing me that my wireless network was too slow and
causing him to not win bids on eBay. It really means that the kids
are losing games because of the packet loss, but I still get to waste
about 30 minutes explaining it to the parents, and again to the kids.

Anyway, I wish you good luck, much profit, and continued sanity after
dealing with strange problems that always seem to wreck holidays and
sleep.


--
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

Jeff Liebermann <jeffl@cruzio.com> hath wroth:

>No file sharing? That's going to be fun to enforce. One local WISP
>does that with a rather high percentage of false positives. I'm told
>that Cisco NBAR (Network Based Application Recognition) works, but I
>have no experience.

More on NBAR:
<http://www.cisco.com/en/US/docs/ios/12_2s/feature/guide/fsnbarad.html>

--
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