Wireless Network Solutions for a Metropolitan Area?

An anonymous reader asks: "I work for a company that is expanding into multiple buildings within the same office park. We have line-of-sight between the buildings and are looking into wireless alternatives. Does anyone have experience with products such as Proxim's Tsunami or Bridgewave's GE60 Gigabit wireless link? The point-to-point links will need to support the usual LAN traffic (SMB, HTTP, SMTP, etc.) as well as VOIP. The buildings are not large--up to 140 users, whose main network use would be e-mail, printing, and saving Excel documents to file servers, as well as the aforementioned VOIP). Are these connections any more secure and reliable than using something in the 802.11 family of protocols?"

Comments

The US's oldest metro-area mesh

[Baldrson]

I designed and deployed the first metro area mesh network in the US using Locustworld's MeshAP software. It wasn't and isn't big (small tourist town) and it required a lot of babysitting for the first year, but its a pretty mature technology now and the price is right (the software is free unless you start getting into the WISP stuff they sell).

At this level - pay the money

[ejoe_mac]

If its all in one complex see about the options to having fiber pulled inside existing conduits. Otherwise it's time to justify the cost over a number of years, and allow for a redundant pathing setup & better hardware. Do 3 links and run OSPF on the back side - that way you're safe in the event of one link failure. Also consider CanoBeam (Canon) free air optics http://www.usa.canon.com/html/industrial_canobeam/ canobeam/canobeam130.html which may also work better for you, depending on needs.

Keep in mind that fog and tall buildings can impact performance on laser based systems, but compare this to everyone 's wifi APs as background noise. Just make sure to go to either licenses bands or the 5.8ghz range if you go the radio path.

Re:Laser Link

[HavokDevNull]

Saw this at a trade show this year (see boss I do learn from these things) http://www.lightpointe.com/home.cfm and from what I saw they have the technology and the bandwidth to handle most LAN's today. I did ask the rep if fog, rain, and snow etc... plays a part in the reliability of the connection. He said yes it does but you have to have major conditions (hurricane) for the connection to drop completely. If you go this route I would ask for a demo of it and research more QOS issues.

Not really a metro question, it is point to point

[jwkane]

Good question. What you are looking for is a point to point bridge. At short range with good line of sight there are only three relevant factors. Price, Speed and Quality.

If price is irrelivent, a free space optic (like gigabeam) with an RF backup (like a Tsunami) will give you massive amounts of bandwidth, low latencies and lots of 9s for uptime/reliability.

Price is rarely irrelivent. A more economical option would be to skip the FSO and just use something like a Proxim QuickBridge. Another alternative which hits a nice price/performance/reliability is a Trango Atlas (45Mbps, about $3k). Most inexpensive (ala 10k) and the licence may be an annual recurring cost. Licence costs depend on location (city/county/state).

So for rough ballparks...

FSO w/RF backup, 1Gbps, $25k +
Licenced P2P RF, 100Mb, $12k + Licence
Unlicenced P2P RF, 54Mb, $3k (Trango)
Unlicenced P2P RF on-the-cheap, 54Mb, $1500 (Microtik, other 802.11x based systems)
Unlicenced P2P RF ultra-cheap, 54Mb, $400 (WRT54Gx2 w/Sveasoft firmware, external antennas)

Rain fade on 38 GHz microwave

[billstewart]

I work for a carrier, and we occasionally use 18GHz or 38GHz equipment to provide access or access diversity. It'll carry up to an OC3 or so depending on exactly which equipment you use, requires line of sight, etc. The limiting factor for us as a carrier is that we're expected to offer a service level agreement, and the amount of heavy rain an area gets determines how long a distance we can go before we drop below 99.99% uptime. So Phoenix can get up to 10 miles or so - Seattle's a lot lower (though not as low as you'd expect, because they get lots of light rain. Houston's worse.) Most of the US older-48 states get 2-3 miles.

Then there's backhoe fade. Guys named Bubba driving heavy equipment are not your friends....