Scott,

Thank you so much for your advise. My application will be using 1310 or 1410 as a bridge(One root and 2 non-root). So I am not concern about LWAPP. But as far as I know we have 1310 series available with outdoor antenna.

(http://cisco.com/en/US/prod/collateral/wireless/ps5679/ps5861/product_data_sheet09186a008022198b.html)

The distance between bridges will be around 200-300 meters and will carry 10mbps worth of data. What will be the best solution 1410 or 1310? Can I manage those bridges from HTTP? Like doing periodic updates or firmware upgrade and other necessary task? Which antenna selection would be better in case of 1310 or 1410 for root and non-root bridges? Which bridges you suggest for campus environment?

I may be asking so much but I am going to use this product for the very first time.

Thank you once again.

I realize you are saying that you only have 10 mbps of data, but you have to remember that you are using point-to-multipoint so you would need to consider the cumulative throughput of the two non-root bridges back to the root bridge. Also, the 1310 is 802.11g only - do you have a clean airspace outdoors to use 2.4 GHz? You need to do some testing with your choice of antennas and distances. This is not something you can just input some specs, order from a catalog and install. There needs to be some onsite verification using the equipment you have and to measure your throughput. If I were chartered with doing something like this, I would perfer to use the 5 GHz spectrum due to the fact that it is a cleaner airspace and would perform better in a point-to-multipoint scenario. But I still would use some tools (laptop with Ekahau or Airmagnet, Spectrum Analyzer, etc.) to find out what frequencies are nearby. Since the 2.4 GHz and 5 GHz frequencies are unlicensed, not only do you want to use the one that will work best for your given environment, but also one that will be kind to others around you. As for the manageablility of the bridges, yes, you can access them via CLI and HTTP for the purposes of performing firmware updates. As far as antenna design goes, I'd use a patch of some sort for the root bridge, and a directional high gain for the non-root.

Regards,

Scott

Scott,

Thank you so much for giving me wider vision. I will really consider your points. I would like to go for 1400 series but only thing is bothering me is the cost which is almost 4times than 1310 if I am not mistaken. Is it just because of it is using 802.11a standard? I was thinking about using omni directional for root and sectoral for non-roots. What do you recommend?

Thank you.

I can understand your concern for the cost of the 1400 series, but the 1400 series is built for point-to-point links for up to 25 MILES!! Obviously less in cases of point-to-multipoint. The 1310 bridge can go a couple of miles as well, but the data rate is going to suffer at 2.4 GHz 'g' only. That's why I said to do some testing to verify you can get the data rates you need to support your application. The only time you actually want to use omni directional antennas with bridging are if you are creating a mesh or a repeater. For PtP to PtM, you would reduce your link budget, distance, and overall throughput by using omni directional antennas. The fact that we use the term 'point-to-point' tells you that you only want your signal to go from the root to the non-root and not elsewhere. Since we can't really contain wireless signals once they're in the air, it's up to engineers to design antennas for us that essentially cheat physics and shape the antenna pattern so that it is directional. Higher gain directional antennas will have a high 'front-to-back' ratio (F/B ratio) telling you that a certain percentage is going in front of the antenna, and a certain amount is going out the back. When the amount going out the front exceeds the amount going out the back, you begin to have a directional antenna. In addition, at larger distances, if you don't use directional antennas, it will be very difficult to align them and keep a stable connection due to the fade margin of the omni directional antennas. The bridges have a built in alignment mode with lights to help you achieve maximum throughput. When you align them, make very calculated, small changes. Don't move both sides, and don't move in both planes (horizontal, vertical). Keep your antennas pointed at one another using some binoculars or other pointing devices and get the best reading you can at the root after an initial setup. Then lock the root into place and go to the other side. Again, make calculated changes to vertical until you find the best, and then lock it down. Finish with sweeping horizontal until you get the best and lock it down. It may take you several iterations until you get it right. As for the non-root antennas, you don't want to mix antennas too much if you can avoid it, but in the case of point-to-multipoint, you've got it backwards. You want a larger angle on the root bridge, and high gain directional on the non-roots pointing back to the root. It is imperative that you know what the polarization is of each antenna (vertical vs. horizontal) and that you MATCH that polarization at both ends. Most antennas have this clearly labeled on the antenna itself, or it is specified in the user manual.

Good luck!

Thank you so much for detailed explanation. With my application I am not much worried about distance because the maximum distance will be 300-400 meters between two bridges no more than that. I am much concern about throughput but in both the cases maximum throughput I can achieve is 54 mbps. Of course the distance will be reduced in case of 1310 but as I said distance is not an issue because in both case I can achieve the distance with maximum data rate. What do you suggest?