Designing Wireless Network

[philote]

Our company is building a new facility and I am trying to design our physical network. My question is, what should I take into consideration when figuring out where to place Wireless AP's? I saw on one wireless vendor's web site that you can get 54Mbps up to 65ft(20m) from the AP and an omni-directional antenna could boost that by 20-25%. Does this sound about standard? Is there some kind of rule-of-thumb I can use to account for walls or number of users when placing the AP's?

I was thinking that I would try and make it so that no one is more than say 60ft from an AP and that there wouldn't be more than about a half dozen on one AP under normal circumstances. But even so, there may be places where the signal would have to go through about three or four walls.

Any help will be appreciated!

 

[BNPMike]

You need to get the building plans. Coverage will be affected by all sorts of metal fixtures and by thick walls. Normally you would install transmitters and then go around measuring the signal in all the required areas. If you need to do it in advance, get in the professionals.

 

[tharder]

That a good starting point. We do that when installing AP's in manufacturing plants. The reality is that a LOT of things affect the RF signal. We use mostly omni antenna's however you'll find yourself using a variety depending on the shape of your building and obsticles such as elevator shafts and equipment rooms.
You'll be surprised how one wall will pass signal fine and others not at all. We placed a unit in what we thought was a perfect spot only to find that the drywall wall next to us had an RF barrier in it. Also, if you are in an open area with fabric covered cubicles, they absorb lots of signal as well.
Pick your spots, tack up an AP temporaraly and walk your site using a signal strength tool. Many nic's come with that utility now. Some come with the ability to pass data back and forth with the AP to get more realistic test data. Document your results, refer to it later when you have problems. Hope that helps.

 

[philote]

Yeah, that helps some. Thanks.

I do have the building plans, which I've been looking over. I need to decide where the data drops will be so we can tell the contractor where to run the cables. That's why I was hoping to go ahead and figure out where I should place the AP's. We do have a couple open areas we'll need to cover, one of which will have some sort of cubicles. I don't know yet how the walls will be constructed in the building or on the cubicles. I've heard it's cheaper and easier to over-wire the building to begin with then have to go in later and run extra cables.

Does it make a difference how high/low the AP's or antennae are placed in a room? I was thinking they'd be up high, close to or on the ceiling, to be less visible.

The area the wireless will cover is mainly offices, meeting rooms, and a break room. We may decide to have wireless access in part of the warehouse as well, but that shouldn't be a problem since it's a pretty big, open area.

Also, some of the AP's signals will likely leak into the parking lot and other areas outside the building. While we're not in a populated area I'm still concerned about security. Making sure we have WPA enabled on the AP's should make us pretty secure, right?

 

[odot]

Use wep and open key 128 bit encryption, radius server with EAP.

 

[vipergg]

you need to do a wireless survey of the whole area . Basically put an access point in a position you think would be good and basically walk around the area with a latop and a wireless nic and see what kind of signals you would be getting . Wireless is basically line of site so make sure there are no obstructions between the AP and where you wish to recieve the signal . It's a walk around and see type of operation and make note of what is in the way etc........

 

[BNPMike]

"you need to do a wireless survey of the whole area "

Taking your laptop up to the 3rd floor to do a survey is not entirely the best approach when the building hasn't yet been built, if only for health and safety reasons.

 

[libroos]

Hi,

I'm also looking into getting the appropriate wireless router/AP/firewall/switch (all in one) for my office as well. Please kindly advise.

Currently, we have one ADSL usb modem as well as Ethernet modem. There aren't any Servers in my office network. It's on Workgroup sharing.

Please advise. Thanks.

Rgds,
libroos