Best WAP For Dense Crowds? 178
An anonymous reader writes "A local community organization has asked me to help them set up Wi-Fi access for an upcoming event, with some unusual (to me) requirements. All users (up to 500 people) will occupy a relatively small area and more-or-less have line-of-sight to the WAP, so issues like signal strength and wall penetration don't matter. Security also does not matter, as we plan to open this to anyone wanting to connect. Cost always matters, but we realize a $50 Linksys or three won't cut it here.
In the past, I have used Cisco AP1200s for a few dozen users to great satisfaction, but they only handle 50 connections at a time, and practically count as antiques at this point anyway. My research on the matter tells me that 802.11n performs far better in this regard, but I want to support 802.11g as well. I have no objection to using two APs to split those apart (with n limited to 5.8GHz, as per the suggestion of several comments in a recent Ask Slashdot), but physical constraints make it preferable to minimize the total number of APs needed — Ten WRT54s might cost about the same as one Aironet, but I only have three good places to mount these.
I welcome any suggestions and real-world experiences with similar situations, including the ever-popular Ask Slashdot refrain of 'What kind of idiot would do it like that, when you can just do this?' Ideally, I would like to know model numbers and how well they held up under real-world loads comparable to my situation."
Mikrotik a possible choice? (Score:5, Interesting)
Choices (Score:4, Interesting)
I have a Netgear WNDR3700 that I use as an access point. It has a lot of good features including two independent radios (2.4 and 5 GHz), gigabit switch and a pretty fast processor. It is about as good as it gets for hardware of its type.
The firmware based on OpenWRT. Some of the features like the attached storage are dodgy, but that doesn't matter for this application.
For your application though - high density, lots of users why don't you take some of the load off the airwaves by offering wired connections too? People who aren't actually physically roaming will appreciate the choice and better performance of wired.
Re:you will need more than 2 APs (Score:3, Interesting)
He's only got physical room for three access points (or, more likely: three clusters of access points).
There are three non-overlapping channels. So, 3 channels * 3 clusters = 9 APs, maximum. But 9 APs * 50 users each 500.
It's important to remember that 50 is just a useful number, and needn't be a hard limit: It's not spelled out in 802.11 that "there shall not be more than 50 users per node."
And besides, it's not like folks are going to physically locate themselves for optimum WiFi distribution. They'll be wherever they are. There's always going to be more than, or less than, 50 users per access point eventually, no matter what. Nevermind the fact that even running in a somewhat degraded state, these 9 independent access points are NOT going to be the bottleneck -- the backbone to Teh Intarwebs will be.
So:
1. Use three clusters of three WRT54GL (the L suffix is important, in case the asker doesn't know -- Google it), all running OpenWRT or Tomato or somesuch freewheeling firmware.
2. Turn the power down. Lots. More power means that the contention issues of 802.11 get worse, not better. A bit of low-tech experimentation with a couple of devices (any old laptop, a jailbroke iPod Touch, an Android phone, etc) will help find the sweet spot for power in that environment.
3. ???
4. Profit!
HP/Colubris (Score:2, Interesting)
HP ProCurve has dual radio products from their buyout of Colubris... check out the MSM422. You can run 2-3 of these @ low to mid power with one radio on N (@ 5ghz) and one on b/g (channelized). That should split the traffic up a bit (most newer laptops have 802.11n cards) You should be able to get 200+ users per AP as long as no one tries to connect from the parking lot (hence the low power).
You can also use some narrow-field sector antennas and "columnize" your signals across a room.
If it is a more permanent installation, consider a distributed/engineered antenna solution (DAS) that will limit the signal bleed outside the intended area (and in turn, increase the connected capacity of the AP. DAS solutions get expensive though. So unless you have other signals you want to inject (cell, licensed radio, etc...), this may be out of the cost range you are looking at.
And for the record, I work for an HP reseller (we sell/support other vendors as well).
Why are you buying? (Score:1, Interesting)
I hope you're not planning on buying anything when a better way to do things would be to rent/lease/hire some equipment for the job. Which is hard to place, since you gave so few details. 500 people, but what, if any networking connection will they need? What is the real intent here? I can understand being a little vague, but there's a point where it's hard to help, and it really seems like you're expecting a magic solution to waft you way.
Won't happen.
Re:Asus RT-n16 (Score:2, Interesting)
The RT-N16 is 2.4GHz only which will be terrible for this scenario. The OP needs to use dual band routers to utilize both bands and maximize the number of clients that can be supported in a small area. 2.4GHz only has 3 non-overlapping channels and if you figure 50 per channel then that's 150 users for 2.4GHz. The 5GHz range has far more usable channels and the majority of N adapters can utilize either band.
Xirrus (Score:1, Interesting)
Take a look at Xirrus access points... they're designed for high density applications.
However, they are expensive.
turn of 802.11b!!!!! (Score:2, Interesting)
I addition to my other comments...
Turn off 802.11b. Very few devices still use it but if you enable it the backwards compatibility mechanisms will slow the network to a crawl. It is usually done by disabling the speeds 1, 2, 5.5 and 11Mb/s.
In such close proximity and no signal strength issues i would also recommend making sure you add higher basic rates ( i have no idea what vendors other than cisco call it) as if everyone is connecting faster (whether or not there is more throughput is irrelevant) then this will up the management and control traffic to a higher rate freeing up even more spectrum.
Re:how cheap? pfsense? (Score:3, Interesting)
Aruba (Score:3, Interesting)
Meru Networks... or cisco/Juniper/foundry/Extreme (Score:1, Interesting)
http://www.merunetworks.com/ps/security/index.php
I would do a controller/WAP and possibly a router for everyone to authenticate too. But then again, 500 users on wifi is like beating a dead horse... Nothing beats hard wiring to every user. I would say if this is something like a large business, large RV park, Apartment complex, etc, I say bite the bullet and invest in the right hardware to do the job. Consumer grade products are not going to get you anywhere. So enterprise grade or bust here. You can probably run fiber optic to each corner and a few in the middle, connect to a small switch and hard wire where ever or attach your WAP and run them 100M in what ever direction.Shielded cat6 comes to mind for this task.
Good luck setting up 500 users on Stable wifi in the same community, because if you can do it, patent the method...
Re:how cheap? pfsense? (Score:4, Interesting)
Re:Asus RT-n16 (Score:3, Interesting)
Use ALL 14 WIFI channels ! (Score:4, Interesting)
I have read very good recommendations of having cells of WIFI routers giving 1,4,7,11 in one, 2,5,8,12 in another and 3,6,9 in the third, why lock yourself in?
In Japan, you can use all the 14 WIFI channels, and if your event is the ONE TIME thingy, use all 14 channels !
Do a 1,5,9,13 on router A, then 2,6,10,14 on router B, then 3,7,11 on router C and 4,8,12 on router D on group them into one cell.
Try push all the users of router C and D to 5 GHz band, router B to 3.6 GHz band and router A to 2.4 GHz band.
Use directional antennas, aim router A to North, router B to East, router C to South and router D to West.
Then set up cells within the premise.
In that way the signals that overlaps are not of the same channel, and not in the same frequency band either.
Re:how cheap? pfsense? (Score:4, Interesting)
This is the thing, more than one problem to deal with in the same physical space. Cheap AP equipment may give you issues under load. With just a couple connections a cheap Linksys will work fine, push the load on it and I find that performance degrades exponentially with traffic increase. Home routers are not built/designed for business loads, or 500 user environments.
The problems: limited mounting space, limited frequencies, limited to mix mode, client movement, (re)registration issues and so on.
Since none of us know the exact physical construct of your problem, suggestions of directional antenna systems, alternating channels etc. have to be used. Cellular systems work in similar ways. 11g mode pointing north/south on chan 2 and 8, 11g mode east/west on chans 5 and 11, ne corner with chan 3 etc etc etc. The low tech testing/wardriving to find the right power levels is a solid suggestion, though this might limit your choices of AP equipment. Pick AP gear that can give you flexibility with antenna systems, power levels, op mode and channel settings.
You will also have to adjust your planning to account for movement of clients. If they are likely to move from ne to se physically, will they need to re-register? Is that a problem? It takes a lot of thinking to get this job done. Enterprise gear will take you toward meshing, and on the pricier end of things move the control out of the AP to allow better performance independent of physical movement.
All of this can get a bit trickier if you have multiple floors with large signal loss between floors. At that point, antenna systems become a stronger tool. At some physical point you'll find clients seeing enough sig strength to end up bouncing on/off one ap and off to another, then back again, never really staying registered long enough to do any good. There you have to fine tune signal strength. Some of the higher end meshing gear gives you options to deal with that, but that becomes a budget issue.
Start with your fixed constraints, evaluate how fixed they are. With some antenna systems, you might find that you have room in more than three places to use APs which would dramatically change your overall problems. The actual AP gear you choose will help discern what you can do about the remaining problems. Don't be afraid to call a sales/marketing engineer for advice, it's usually given free at some level of interest. That's not even to mention this: http://lmgtfy.com/?q=how+to+set+up+mesh+mode+wireless+networking [lmgtfy.com]
I think that the process of trying more to understand what the real problems you will have is going to help you further figure out what you need to do.
One last thought, an extra 1500 bucks on the limo now is a lot less than you would spend to find one ready to go on prom night, so to speak. Read to see what the equipment on your short list does under load, how it works in high volume situations etc. that lmgtfy link might show you some good examples to read about.
Re:Not cheap, but... (Score:2, Interesting)
We (citylink.co.nz) provided the wireless (the AP's, not the DHCP and routing) for the recent LinuxConf AU conference in Wellington, NZ. There were something like 700 attendees, and you can guarantee every one of them had at least one wireless device.
We used the Xirrus devices and apart from a couple initial teething issues I believe they coped well with the load.
I think we were using the big 8 radios in a single flying saucer like device, and we used multiple units.
We have used the Mikrotik AP's in the past and I'd agree with comments made by others, they top out at around 50 users.
I wasn't personally involved with the conference, but if you hit the "contact us" link on our web page we'd be happy to provide you with the exact models used, code revisions, and answer your questions (as best we can).