WiFi Bridging?

An anonymous reader asks: "I have a wireless network on one side of the street, and want to connect a computer on the other side of the street to it. Unfortunately this computer is behind a nice solid metal wall, and can't really be positioned near the signal. Currently I have a 20' USB cable going to a USB Linksys 802.11b unit, and a 20' RG58 cable going to a 14dB antenna and a PCI Linksys 802.11b card. Both of these cut out about once every 30 minutes, for about 5 seconds at a time. I also have an Airlink 802.11g PCI card and a Netgear 802.11b PCI card. What's the best way to connect to a kind of weak (-65db) signal? Can I use a wireless bridge in reverse, telling it an SSID and plugging the other end into an ethernet card? Which WiFi card has the most reliable software, that doesn't drop the connection all the time? I haven't been able to find much real info on this. Any help is appreciated, thanks!"

Linksys WET 11

[Anonymous Coward]

Get a linksys WET11. I'm currently using one for:

airport -> wet-11 -> ethernet -> mp3 player+ airport -> tibook with crappy antenna.

It's had one hiccup in the last 14 months that it's been up.

Firmware

[Drew M.]

For starters, make sure the firmware on the routers is updated to the latest version if you experience dropouts. I had major dropout problems until I updated the Dlink access point I had. Also a signal level of -65db isn't bad at all if your noise level is around -100db. Right now I'm running at -72db with a noise level of -99db, but I've been all the way down to around -90db and have it remain useable. I'm shooting about 2 blocks over with line of sight.

Ethernet, not USB?

[MBCook]

I would try going with ethernet, not USB. The basic idea would be to mount a little ethernet to wireless device somewhere (and connect it to your antenna). If the thing can use Power over Ethernet (and you can supply that) then you'd only need one cable going to the device. By keeping the device near the antenna, you don't have the signal loss that your long antenna lead has. Something sort of like this [dlink.com] from D-Link [dlink.com].

In fact, there are other devices that could make this even easier. I saw that Linksys [linksys.com] will be comming out with what may be the perfect product [linksys.com] for you.

Now you should know that there are other (albiet more interesting) options. If you want to go for pure coolness and geekocity, I have just the thing. My brother managed to get a laser link for connecting networks between two buildings a few years ago. With think it's not functional (never tried, think parts might be missing), but it's a cool thing. We have two large units (look like outdoor security camera casings) that each have laser units in them. You point them at eachother, wire everything up, and voila! the networks are supposed to be connected. They were used at a local school years and years ago. Ours are probably slow, and we know they are tolken ring (that's about all we know) but they exist. You could probably find something similiar if you looked enough.

As for your current problems, I don't know. I assume you are running Windows? If you were running Linux you could find out WHY the network is going down (watch for errors from the USB subsystem) but I don't know how (or if) you can do that in Windows. My guess is your 20' USB cable is part of the problem (just a hunch). Also, are you using directional antennas? Not just directional (in that they are not omni-directional) but HIGHLY directional antennas (like Yagis or the pringles WiFi antenna)? That might help too.

Also, now that I think of it, I think many accesspoints have an option to bridge networks built in. A quick check says that my Netgear WG602v2 supports it. But it looks like both ends have to be operating in "bridge mode" (although you can still serve clients in bridge mode, it looks like). So that's a 3rd option.

Cantenna?

[millisa]

What about using a directional antenna? The cantenna [cantenna.com] might get your signal over there better . . . Unfortunately, it doesn't appear to be sold with cookies anymore . . . You could also try one of the pringle can DYI antennas and see if it helps?

You want a client bridge

[Gaewyn L Knight]

Tiny little boxes... connect via wireless to another AP and provide a single ethernet port out.

Senao (Engenius Tech) makes 2 nice little boxes for doing this that have 200mw transmit and the best receive thresholds on the market. This puppies have NICE radios.

You are looking for either the NL-2611 CB3 (802.11b) of the NL-3054 CB3 (802.11b/g and is also bi-mode [can operate as AP and client at same time])

Just through a network cable in place... connect this... adn ditch that USB crud.

A few suggestions

[gtoomey]

I've written a basic linux 802.11b wifi HOWTO [gregorytoomey.com] to help people with basic connectivity issues.

A commercial 14dB antenna is high gain for wifi and should work for miles, so the dropouts you are experiencing are very strange. I suggest starting a packet sniffer like Ethereal and seeing what happens when dropouts occur.

If you can use a standard outdoor wifi antenna (made by dlink etc) bolted to a bracket, commercial pigtail and limit the RG48 length you should have no problems. You can reduce cable length using power over ethernet.

I'd put an access point at both ends (rather than wifi cards) as it will effectivelty do the bridging for you

Re:Cisco 1300 or 1400

[hbackert]

just remember that you'll get better quality when you buy quality hardware.

While I can generally confirm this, and I certainly like my Cisco AP, this is an overkill-solution-par-excellence. Of course you can go to work with a comfortable car and of course it's faster than a bicycle and of course it will be more expensive, but when your office is 1km away, this does not make any sense at all. Cisco bridges are great just like Cisco routers/switches etc., but I would not recomment anyone to buy a Cisco router/switch for private and small networks. It's just not worth it and most people cannot use nor do they need all those nice features. In a company, stay away from generic stuff with only web interfaces and get the good, expensive Cisco & Co stuff, but at home it's the opposite way.

I had a similar problem (2 networks to be bridged, albeit shorter distance) and I did this:

• Set the access point on once side of the network (that was the simple part)
• Set a Soekris 4521 [soekris.com] with a CardBus WLAN card on the other network
• Let the Soekris connect via WLAN card to AP
• Bridge traffic between ath0 (the WLAN card) and eth0 (the onboard-LAN).
• Use eth1 for connecting to the Soekris for management purposes, but I can easily live without it as it works reliably.

Costs: I had the AP, I had the Soekris box, I had a PoE adapter, I had to buy a CardBus Linux supported WLAN card (Atheros) as I could not use the PCMCIA Prism card I had. Costs for me: 7000 Yen (approx. US$70). Costs for someone without all this stuff: about US$400 for all of it, which includes a Soekris board which is likely overkill for this one job. But it's very reuseable, so I could this as an investment.

Another option was the purchase of a Ethernet-WLAN bridge (connects to an Ethernet port, has a small computer inside with WLAN on the other side, and it's simply bridging stuff from left to right and right to left, just like the Soekris does). Costs 9000 Yen here in Japan. But it only good for one Ethernet port (1 PC, not a network).

Both beats paying US$3000 for a Cisco bridge set and the former is far more versatile while the latter is easiest to set up (if 1 PC is all you need). Setting up thr Soekris is dead-easy if you've ever set up Linux routing/bridging/WLAN, before.

Linksys boxes

[Gid1]

I just did something a bit like this. I live in an apartment in the same building as my office, but it's on the other side of the building. Minor detail: the building is L-shaped, and home and office are on the different branches.

I spent a month or so going through different options: looking for a third point on the other side of the street that could act as a line-of-sight reflector, investigating existing cable ducts with phone wire and that long range ethernet thing.

Finally I decided to get a directional antenna (this one [wirelesspro.co.uk]) and a new Linksys WRT54G [linksys.com]. I had an existing WAP54G [linksys.com] which I use for the other end.

The WRT54G is in my hallway at the apartment, stuck to the wall above the entryphone. The WAP54G is in my office, with the antenna bolted to my office balcony. Using the Sveasoft [sveasoft.com] firmware, I've boosted the signal a little and have established a ~2Mbps bridged link by blasting the signal through the apartments in the line of sight. The WRT54G acts as a repeater for my laptop. Since the office only has a 2Mbps line, it's good enough. The people in the apartments between might start having funny-shaped babies, but I've got free connectivity, and that's all that matters!

I'm sure it would be better if the home-side box had an external antenna, but it's intrusive enough in my hallway anyway. I'd also then be able to use the stock firmware. The Linksys boxes are relatively cheap and thanks to third-party firmware are extremely configurable.

As far as the 5 second break every 30 minutes goes, I'd guess it's some third-party box negotiating something (eg. NetBIOS or NTP or something) and interfering with the signal on your cable runs.

Re:You want a client bridge

[Anonymous Coward]

agreed. In my old office we had the same situation: the only way to get broadbad was to run it from across the street, as Verizon would connect lines on that side of the block, but not ours. Our landlord occupied that building and was happy to let us run in a phone line and put a 802.11 DSL router on his window ledge, so that was our solution. Problem was about 60 feet and multiple steel-reinforced brick walls. Our soultion was the same offered by the parent post, except cheaper: we used a Netgear ME101 bridge, which is a $40 Staples item. We still suffered sporadic outages, but uptime was gernally around 99% and once we mastered resetting the hardware in the correct sequence we could resolve any outage in seconds.

Note that we experimented with affixing a homemade Cantenna to the bridge. While this definitely boosted the signal, it added a new problem. Since it's directional, ever time we would accidently jostle it (it perched percariously on a windowsill) it would go down immediately. We eventually just put the Netgear factory antenna back on the bridge, as it meant one less point of failure. While the occasional interference would cause it to lose the router, since this only happened every few days, it was no big deal.

First find the problem

[WyerByter]

I am not a WiFi expert, but it seems to me that all the experts so far have missed a rather large detail. If your signal cuts out on a regular or fairly regular schedule, then there might be something external to your setup that is causing the problem and would cause problems no matter the set-up. You said the signal crossed a street, maybe every half hour a car stops exactly in the path of your transmission - transmission interupted. Or perhaps a vehicle travels by with a powerful radio transmitter (cop, firefighter, trucker, trucker wannabe). Another thing to consider is how close you are to a radio source (antenna, airport, publice safety facility, resistance cell, whatever). Again, I am not an expert at WiFi, but I have a lot of experience in trouble shooting and debugging, if you try and fix your problem without first determining it is not external to your setup, you may be just throwing money down a rathole.