Fastest Bridging Configuration

Maybe someone can direct me to a previous post, but simply, I'm looking for the fastest wireless link I can set up (bridging). I have two LANs (separate buildings) that are 0.4 miles apart that I want to bridge together.

I've set up past links using Buffalo WHR-HP-G54s running Tomato Firmware. I get low latency with 25Mbps max of throughput (with semi- parabolic grid antennas - 24dBi). Given that Buffalo can't sell wireless equipment due to an injunction, I cannot go that route again. Besides, I'd like to go faster.

I've thought up some ideas on ways to leverage standard 802.11 equipment. Some thoughts:

  1. Channel bond A & G radios in a dual-radio bridge, such as the Cisco Aironet 1240 (no success there yet).

  1. Run two bridge links and bond the two links at each end with a capable switch (Cisco calls it "EtherChannel).

  2. Bridge with 802.11n (Draft 2.0). I understand that some of the new technologies of N still are effective in narrow focused beam configuration (24 dBi SPG antennas) over G. Maybe use antennas that have broader coverage if MIMO can be taken advantaged at that distance.

  1. Full-duplex (Not to spec, I know) / transmit on 1 antenna, receive on another (with difference polarization). Or use multiple radios, one that transmit on 5 ghz, but receives on 2.4 ghz (is that even possible?)

I'd like to hear of some (better) ideas, especially what has actually worked. I can probably spend a $1000 on each end for the radios if I can get better speeds.



Reply to
Loading thread data ...

You could try getting a pair of AIR-AP1252AG-A-K9 (under a grand apiece street price.) 24dBi is overkill for this app; Yagis make sense. (3 per AP, ideally a couple feet apart. Should be able to get 100Mbps HDX at least? (Remember to use AES if you want 11n rates.)

Should ought to work, although you'd be something of a pioneer.



Reply to
Aaron Leonard

That's about 2100 ft.

You can squeeze out a bit more using the various 108 or 125Mbit/sec consumer routers. For example the Buffalo WHR-G125.

I haven't seen anything like that in a single box. It can be done with two boxes, but not easily.

Look for 802.3ad or Link Aggregation Control Protocol

I've used two parallel 2.4GHz bridges for redunancy and reliability. As an added bonus, the total thruput was considerably higher than with a single link. I tried something cute that didn't work. I initially had an ordinary ethernet switch at each end. I just plugged two wireless links into both ends expecting thruput to be roughly twice that of a single link. It was faster, but not quite twice. The ethernet switches did not provide the necessary load balancing. SNMP showed that most of the traffic was going via one or the other wireless link, while the other port just sat there.

I've been thinking of going into the antenna business. I hope you like that way 3 antennas look at each end. 24dBi is overkill for

2000ft range. Methinks about 12dBi would be quite sufficient.

Yes, it's possible with non-802.11 implimentations. For example, Proxim Lynx radios split the 5.7GHz band in half. One half goes in one direction, while the other band goes in the other. Real full duplex (with a cavity duplexer on the back of the Lynx radios).

The way it works with 802.11 is that you can simulate a full duplex connection by going twice as fast on the wireless link. The radios switch direction depending on which packets are going in which direction. With buffering at each end, it looks just like full duplex at half the wireless rate.

I don't think you can do it right for $1000/end. Maybe with used hardware. Look for 5.7GHz or higher frequency hardware. For example:

Orthogon (Motorola) will go at 44Mbits/sec ethernet thruput up to about 3 miles:

If you go to 22Ghz or 60GHz, the available speeds are even faster.

125Mbits/sec ethernet thruput is possible:

Just, don't ask the prices.

After you've done the requisite window shopping, look on eBay for various Buffalo wireless products. Search for "buffalo wireless". There are plenty available (at rediculously high prices).

Reply to
Jeff Liebermann

We use two 5.8 Gig units at each end with the 22 dBi BBQ grid antennas on the transmitters to keep them legal and 32 dBi solid dish antennas on the receivers.

You can use 5.8 Gig, but there are only two non-overlapping channel configurations that you could use: 149 & 162, or 153 & 165, or possibly three: 149, 157, 165 if you deploy it right. Or you could use 5.8/2.4 combo.

If reliability is not an issue, you could use any one of lower power

48 - 64 channels at one end, and any one of the higher power 149 - 165 at the other end.

Even with a grid or dish antenna, you need to keep them at least or about three feet apart to prevent desensing of the receivers.

Reply to

links into both ends expecting thruput to be roughly twice

, while the other port just sat there.

Was this with LACP?

I'm looking at Trango's TrangoLINK-45 -- they claim 45Mbps of throughput for a set of radio for $2000 (promo right now) w/integrated

23dBi antenna.
formatting link
Reply to

No. It was with two junk ethernet switches that did not have 802.3ad features:

It might have worked if I had fancier switches available.

I've use other Trango products. Crude documentation, limited monitoring (SNMP), marginal support, some quality control problems. I wasn't thrilled, but it eventually did work for me.

Well, you could get 50Mbits/sec using two "aggregated?" 802.11g links at 25Mbits/sec each. The cost would be much less than $2,000, but would be rather messy with two antennas at each end.

Reply to
Jeff Liebermann

Here are some nice 1G laser units that I looked up for fun :-

Geodesy FSO Pronto SuperGIG 1000Base-T copper RJ45 Interface Maximum 1000Mtrs. ONLY =A314390.00 + VAT Pair

A bit over budget?

Reply to

Budgets are made to be broken. I can proudly say that I've never even come close to staying within my original wild guess proposal estimate. I don't mind being wrong, as long as I'm consistently wrong.

Thanks for reminding me about FSO (free space optics). There are slower and cheaper LED based solutions. I've used FSO boxes from Plaintree in Canada:

in the past with good results. The big problems are fog, direct sunlight pollution, stupid birds, and parnoid neighbors. At 2000ft, even their lowest end "indoor" boxes will work. The only prices I could find was from 2000 when a customer bought a pair of something for about $9,000/pair. I guess it's lower now, but I can't find any current pricing.

I helped setup a pair of these:

(in the rain). They work nicely when the lenses aren't wet. Here's one (or two?) on eBay:

for $2,000.


Reply to
Jeff Liebermann Forums website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.