Advice needed on Wireless Network Card (amongst other things)

On Thu, 14 Feb 2008 20:46:52 -0500, armando wrote in :

Sounds like a crappy antenna, or perhaps even a disconnected antenna. Suggest you check out that possibility.

You do know that actually throughput will be about half of that at best?

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:

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.

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 hath wroth:

Probably 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."

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.

Range, speed, or reliability. Pick any two.

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

I'm offering two outta three...5 Meg user end point speeds,

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.

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.

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?

On Fri, 15 Feb 2008 16:08:13 -0800, Jeff Liebermann wrote in :

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.

Sorry, it was channel 56 at 5.260 GHz.

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

DTC hath wroth:

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:

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.

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 hath wroth:

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