Long distance network help needed

I need to design a network that is as simple as possible but able to have significant bandwidth over distances of about 700 feet and would like some suggestions.

The system consists of 13 members moving between 8 points from which large files will be uploaded (the uploads will occur only when they are stationary but they wont always be at the same spot) and a non central base station that needs to have a strong enough connection to download significantly sized items in a reasonable time. Access points and any other external equipment needs to be able to withstand rain and the occasional splash of salt water and though there is high speed internet at two of the base points none of the pieces need to access the internet and those two points are in one corner of the area at which I am working.

At first I was hoping to be able to set this all up as a bunch of different peer to peer networks and allow the base station to connect to a member and download the info but then I ran into the issue of what the wireless bridges can handle as far as switching between signals. I want to stay away from setting up a full network (real and virtual) if I can because the information being sent is fairly important and cant really get out and it requires a few more levels of complexity than are wanted in that the area doesn’t have any existing servers.

For the first and hopefully not last (but it probably is) time in my Robotics career I can say that money is not an issue, also I would prefer to work with linksys equipment but the project doesn’t depend on that.

Thanks for the help,
Simon Strauss

First and foremost, you need a better problem definition. If we’re talking wireless, then the environment matters hugely to reception. So you need to describe the area or at least mention if there’s walls, girders, etc. that will get in the way. Second, your bandwidth requirements are entirely too vague. From your statement, I gather either you need to send 10MB files in a few minutes or possibly 500MB files in 15 seconds.

The environment is a dock with no solid bounderies but poor air quality for a wireless signal such as mist, pollution and occasionaly fog. And the information is large video files that need to be done in a round 10 min.

Sorry for the confusion and thanks,
Simon Strauss

How large?

any where from 700 to 1200 MB in a reasonable amount of time

I would recommend using N routers, they have an average range of 800 feet and give you a speed of 300 Mbps if the mobile station has a N card installed. Linksys is good, however since linksys is cisco it has the cisco engine in it. Search the web for linksys firmware mods and you shoudl find a site that gives you firmware that activates the engine (also allows you to install an sd card and use the router as an ftp server, 1 gig max)

The issue is that Linksys doesnt make a wireless N with an outdoor caseing. Thats why I was thinking about the outdoor wireless G they offer but the range on that is not quite good enough.

Is there anyway to set up a wireless peer to peer network between two PCs that can then select and access another item equiped with an access point or would I have to do this at configuration?

Or, does anyone know of a MIMO range booster?

Simon Strauss

What will the range between each station? You could possible do a web type network where they are all connected. Also, does the whole area need to be covered of do you have station where you need wireless? If so you could run some cable and just have the stations wireless.

Well I laid it out all nice on google earth to check my distances and options (my boss said I cant upload it though because the customer would get pissed) and it turns out that I have two clusters in which the wireless G range is fine. Cluster 1 has three possible parking spots from which data would need to be uploaded as well as the control building. Cluster 2 has the rest of possible spots and a maintenance building (723 feet from the Control building) from which I can put a PC but no person will be there to control it. Thing is I need to find a way (either a Peer to Peer to Peer network or a MIMO range booster) to upload files from a spot in cluster 2 through the maintenance building to the control building with only a person in the control building.

If you do use linksys, or any other indoor hardware, you can put them in a PVC enclosure. The AP could be powered over PoE, just make sure you use outdoor cable. The gray box would camouflage the ap and prevent it from being stolen.

so use a linksys in a case, cisco has cases where you insert the router inside of it and it has antennas on the outside which hook up to the router, its very doable , just requires a bit of research, here is the site i get all my equipment from…


router cases http://www.mini-box.com/WRAP-BOX-4A2E?sc=8&category=19

If this application is reasonably important (i.e. customers are paying for it and/or a company will suffer losses if it doesn’t work), I would not recommend using Linksys or any other “comsumer grade” hardware.

I have a WRT54G myself and love it, but all of these devices at various times have had trouble with high traffic loads (yes, even with 3rd party firmware). In fact, I used my 54G to provide Internet access at Midwest with openwrt and an apparent memory leak would cause it to reset every 10-15 minutes since there were 100+ users connected.

Additionally, making indoor equipment ready for outdoor use is not as simple as sticking it in a waterproof case. Electronic devices are spec’d for certain temperature ranges etc. and if you use an indoor device you’ll need cooling and/or heat in the enclosure depending on your location. Keeping humidity out is also a big challenge, as is dust (unless you fully seal it, but then the temperature problem gets worse).

Since you say money is not an issue, look for something designed for outdoor use. Motorola sells dual-radio outdoor hardware that has 802.11b/g and 802.11a all in one unit called HotZone Duo which also performs mesh networking (but it’ll set you back quite a bit more than a Linksys). I’m sure you can find similar hardware from Cisco or other vendors. This stuff costs more for a reason, and it’s not always just because there’s a big-name label on it.

The reason why I want to stick with linksys is that though its not the best for the conditions, the buyer is a beuracrat who is deadset on the twisted theory that systems with multiple brands dont work as well and because there are linksys products already there, they want to stick with Linksys throughout.

one the one hand like system components work better together, but on the other it really doesn’t matter, if you have no choice but go for linksys then i suggest you get some routers, weather proof cases and test it.

I tested with an oven and a big pot of ice cold water… good luck

Linksys makes external N antennas HGA9N.
The access piont can be sealed in NEMA rated weatherproof enclosure with a weatherproof bulhead N connector going to the antenna, and using PoE, the ethernet line can enter the box using a weatherproof rj-45 jack connector. The box and antenna can be mounted on a high structure such as the side/top of a building, or on any other high structure. one device might do the job, but 2 or 3 devices spaced evenly probally would provide the best, most reliable connection. As for security select devices that can use WPA2 encyption. A RADIUS server (ex. Windows server 2003) is needed for the highest level of this method, but a preshared key method can be used. the advantage of using the server method is that you can selectily control what users can use the wireless access and at what times, and for how long.

I realize that this is a common problem in industry… But he’s hired you to be an expert at this. You should atleast attempt to explain both the highly likely reliability problems of the linksys outdoors and the black-box nature of networking. Unless you’re using one of the proprietary speed-boosting features, then it doesn’t matter. Mixing brands only particularly matters from a support standpoint in that it’s a slightly different system to learn. So I think he really needs to decide if he wants less frequent support of a more complex nature, or much more frequent support and outages of a more (soon to be all too) familiar nature.

Again, you’re being paid for your considered and expert opinion, so I think you should politely explain the issues, or atleast present the pros and cons and give your recommendation. And definitely make sure they understand you’ll have to charge for service of the linksys one if it’s found to have failed due to the environmental conditions.

I forgot to mention that it is a municipal project and the whole reason why I have to set it up this way is that the buyer wont let the company who I work for (which has had military security clearance since WWII and has had city and state contracts since before that even) access their servers and set up a more secure/cheaper and effective wireless system. I’ve tried the explanations but the project is for a bunch of ludites.

Latest news: I’ve got most of if figured out but still need to decide how I am going to let the control room access the PC in cluster 2. Can anyone recommend a good secure remote access program (these two have internet access)?

Thanks for the help,
Simon Strauss