does I need a bridge to connect two offices?

[prometeo]

hi,
I would like to connect two offices, one is wired with a switch for a 10/100BaseT. There I would like to connect an AP to create a BSS reaching the other office where the client (with a wireless PCI NIC) will be able to joint the network.
The offices are on the same building on the same floor (the second). Next to the AP there is an 80cm wall (with some windows) than an empty space then another wall about 80cm then the second office. In the space there is nothing (maybe the rain). Between the two area there are about 100/120 meters.

Someone have told me I need two wireless bridge talking each other. The second bridge connected to a switch where the second office's clients will be connect to. Is it true?
Can't I use an AP with a sector antenna?
Or can't I use two AP to create an ESS? I will not able to create a wired distribution system between them, can I configure an AP to work as a wireless bridge?
thanks

[M/Q]

Is there any chance you can test the future link with lets say two notebooks with wireless cards in ad hoc mode? I would be just a little concerned that you set this all up and the signal will not be strong enough to make a good link. Is is possible that you might be able to have external antennas on the outside that could see each other, or if you set this up and it does not work, do you have the option to add the external antennas later? That would help as a fall back position. Next question, do you see more clients in the other office in the future? As that might impact how this bridge link is setup now. What is the client computer in the second office right now and what bandwidth do you foresee that client using. For instance, is it just normal office applications and using the Internet. Or is it possibly a bandwidth heavy application like video streaming. This is important to know as the signal available will determine how much bandwidth you have available. Weak signal, minimal bandwidth. Also, you should be concerned if there are any other wireless networks in the area or other sources of RF interference. One last question, is the AP only going to be used to make the link to the other office?

All that said you have two options. First is what you described setting up the AP in preferably the window. If its only job is to link the other office, then I would add some kind of directional antenna to the AP or use these little reflectors. They work very well, and will double the existing power.

http://osiris.urbanna.net/antenna_designs/projects/template/

There are aftermarket antennas available. You have not mentioned any hardware and I just wanted to give you an idea of what might help. Now for the computer in the other office. The computer depending on what wireless client it has could possible use the reflector or aftermarket antenna as well. If possible in another window as well. I am pretty sure you are going to need some help with aftermarket antennas to get the signal to a level where you will have a good link.

The next option will be required if you decide to have more than one computer in the other office. It is the bridge link you talked about. I might prefer this method any way. You can use two AP's. one in each office, with antenna help as suggested above. the AP have the ability to work as bridges, so you will not need to buy a device specifically called a bridge. You just have to configure them correctly. The AP in the other office would be linked with an Ethernet cable, or if there are more than one computer, you just need a switch/hub to connect all of them to the AP. Just some configuration and the link will work.

Again, I just want to make sure you try and test the feasibility of the link first or have the ability to add external antennas, just so that you don't spend money an find out the wall are too thick of have metal in them that will absorb the signal.

[prometeo]

I have had think about the check with the laptop... and I will probably do it before other moves.
I think adding an external antenna will be a problem cause other people lives in the building. They surely find something wrong with it.
In the second office will be three desktop clients. All of them will do office work, browsing and sometimes two will use a light-database application. I'll check the bandwith used but I think its nothing overwhelming. Thoose clients should even be wired. I've looked for the bridge with two AP, first one on the first office switch and the second can be connected (rj45) to a switch or to another AP to allow the wired or wireless connections of the client right? Can I building the wireless distribution system with a 802.11g protocol? I'm scared about a bottlenek caused by 802.11b protocol on the bridge.

The AP I was looking was this: 3CRWE454G72, the desktop PCI NIC was: 3CRDAG675 (it has a mobile antenna). For the PCMCIA on the laptop I've choice this one 3CRWE154G72 (cause it has Linux driver http://prism54.org/supported_cards.php and it's 3com like other stuff). Without an antenna will this model be good for the ad-hoc connections tests?
I've looked something of linksys but looks like that 3com stuff. The bad think I've found with that 3com AP is I can't just plug-in another antenna.

You were talking about metal in the walls... there is a 3 people lift in the corner between the two offices... :-\ two floors, the office one and the first floor.
thanks

[M/Q]

Since you are going to have more than one client in the other office, you should use two AP's acting as bridges. In the other office all you have to do is connect the AP to a Switch/hub and then connect the computers to the switch/hub. I would try to have some kind of antenna help on both AP's whether it be the link I posted before or a directional panel antenna that can be pointed towards each other. Then if the test goes well, it should work fine. 3Com makes good equipment, just get the best that you can afford, it does make a difference.