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Have you ever used Xirrus? If so, I am curious in this type of deployment. What benefits have you seen using the wireless arrays over the standard AP deployment? Do you like the Xirrus management system? It seems that they have been used in quite a few campus type deployments. What would you say the biggest limitation Xirrus has?

I've seen them around mostly in large conference high density deployments. I think they are a perfect fit for a quick setup conference environment to support tons of users. On the other hand they look like an alien spaceship.

Haha you are right, they do look like space ships. I have never seen one in person. I watched a video on youtube and they are huge!

How about because each array has multiple radios, you protect yourself from clients wanting more bandwidth. Though, it may be too expensive for an office of 5 people.

Yes, the multiple radios will separate high density areas into multiple collision domains. Xirrus promises less devices per area. Do you really think the high gain antennas are that beneficial? We need to remember the other part of the equation, the client radio/antenna. Just because the high gain directional antennas from the Xirrus AP will prorogate further than a normal omni-directional AP, does not mean that the client will be able to communicate back as easy.

I have never deployed a Xirrus AP and I am curious to hear from someone that has.

Interesting point. Consider this. Since we know that client devices are weaker than APs, would it make sense to survey your weakest client (assuming that you can set it to AdHoc) and then place your APs according to your survey results? That way, you will know that you have verified your upstream data rate?

High density 5Ghz deployments are where Xirrus really shines.

Providing wireless connectivity in event / tradeshow spaces such as Keynotes is just too cost prohibitive if you're needing to service lets say 10,000-40,000 users. We've started using Xirrus exclusively for these types of environments, and haven't looked back.

LWAP designs certainly have their place, but Xirrus has really strong armed their way into this particular "high density" genre.

XMS has come along quite nicely since we first saw it. It's no WCS (yet), but certainly has the potential to be a great tool.

As for limitations, per-user bandwidth limits come to mind right away (currently can only limit pps, without the option to limit bps). As far as I know they're working toward addressing that.

Wayne Bishop
CTO
showNets,LLC

Thanks for your input Mr. Bishop!

I get a lot of customers worried about moving towards 5GHz, they say they do not want it because it will not "Go as Far" What are your suggestions to say to a customer who says something like this?

I guess check to see what kind of client devices he has. If the customer has client devices that are only capable of 2.4Ghz then fine, leave it be. This kind of customer doesn't require high density and high bandwidth. If he does, then the size of coverage doesn't matter because he will end up needing more APs to load balance the number of clients he has. Also, It's really hard to channel plan with only 3 channels. You also can't take advantage of channel bonding which only yields 1 40Mhz channel in the 2.4 space (unless the customer lives in Japan).

Of course an AP today can handle 256+ clients, at a max data rate of 216.7 (3x3x3 2.4Ghz with 20Mhz channel and GI @ 400ns). I usually divide the data rate by 3 to get an approximate throughput rate. Divide the tput rate by 256 and there is your maximum rate per client.

How can Japans channel 14 be used in a 40MHz deployment? It isn't contiguous to channel 13.

Do the Japanese allow use of the full spectrum between 13 and 14. Somehow, I would doubt it. That would seem to negate the whole reason of putting a DSSS only channel out there by itself.