30 Laptops, 1 Router?

I need to connect 30 15" Macbook Pros via a wireless network. Initial tests with a Linksys/Cisco WRT54G v6 indicate that it tops out at 10 devices simultaneously, and any further connection attempts are rejected. I need all 30 to be connected simultaneously. What are my options? Cost is somewhat an option (this is for a student organization, so we can get money, but not big money); we're willing to spend extra money for convenience. Things I've considered:

Multiple Access Points, each with a different SSID/channel, all connected to a single DHCP server; manually load-balance (ie, "you, you, and you, connect too Foobar_1; you, you, and you, Foobar_2," etc).
Better access points. Would a 54GL running DD-WRT support more concurrent devices?
Multiple better access points serving as repeaters, wired or wireless?

Also, the environment we're operating in has about 20 existing 802.11b/g networks. We were able to get plausible performance for 10 machines by selecting an unused channel after looking at Kismac to determine what channels the existing networks were on. Would it be worth looking into 802.11a, since that uses 5ghz vs 2.4ghz? I've never needed to simultaneously connect this many machines at once..

Alterscape

Posted 2010-11-06T01:24:55.167

Reputation: 253

You should get like four routers then hook them into each other, then have 10 laptops connect to each router. Would that even work? I imagine it'd be slow as hell but it'd be interesting to try. – Corey – 2010-11-06T01:28:07.660

1Why would you ever need four routers for a setup like this?? Routers are not for just adding more capacity, they are for connecting several disparate networks. – MaQleod – 2010-11-06T01:51:14.977

Answers

I would check out http://www.xirrus.com/ I saw a demo where 96 iPads were connected to a single AP from Xirrus. Half of the iPads were streaming a live video feed and the other half had a script that was browsing the web. I don't know cost but I know from experience getting 30 computers on a wireless connection is not an easy task. The school system I worked for 5 years ago never got it figured out. Technology was different then but Xirrus looks promising.

TechGuyTJ

Posted 2010-11-06T01:24:55.167

Reputation: 250

Buy a real router, not a cheap home router. That many connections, whether wired or wireless, require an enterprise level device to properly manage, not something meant for mild home use.

MaQleod

Posted 2010-11-06T01:24:55.167

Reputation: 12 560

I don't think this is necessarily true; the CISCO "enterprise tax" is pretty heavy. – Jeff Atwood – 2010-11-06T09:27:37.240

1I suppose I should have supplied other options, Cisco isn't the only one. Juniper, edgewater, adtran, netopia, etc, all better than a linksys for larger scale networks. – MaQleod – 2010-11-06T09:29:46.603

Purchasing just one router will not solve the problem. The issue here is the number of concurrent connections. To solve the problem you would need to put in an AP array and that can get messy. The only single device on the market that can handle the numbers he would like is the Xirrus. – TechGuyTJ – 2010-11-08T14:15:32.447

You can have all the access points you want, but if your router still needs to be able to handle a large load. Home routers really aren't built for enterprise scale networks. – MaQleod – 2010-11-12T14:30:25.180

One option would be to replace the firmware your router runs to a third party option. There are two options, DD-WRT and Tomato. I've heard Tomato seems to be more stable of the two, though I haven't had to opportunity to use either. After installing Tomato, you have a multitude of options to enhance your router, including raising the connection limit -- even as high as 4096 connections.

The downside to this is that you mentioned you have the Linksys WRT54Gv6, which isn't supported by Tomato. Below is a link to their supported routers.

http://www.polarcloud.com/tomatofaq#what_will_this_run_on

Drew Watkins

Posted 2010-11-06T01:24:55.167

Reputation: 121

you will have a maximum of 15 connections in the same signal area, so you will definitely need multiple Access Points(APs), and they will need to be spread out. Each one will only support up to 5 connections that will have a useful speed (2mb). You can have all the APs with the same SSID, however i am not certain if home-style APs support this. Hope this helps.

Jimsmithkka

Posted 2010-11-06T01:24:55.167

Reputation: 166

On what do you base these numbers? – harrymc – 2010-11-06T10:51:15.037

number of channels in the b/g spectrum, there are a total of 15 channels, at slowest rate (b) its 2mb per channel, a full b setup takes 5 channels to get the max speed, g uses this same setup at higher speeds, but for each host you add, you divide the throughput per single AP – Jimsmithkka – 2010-11-10T12:14:26.243

the most you can have is 1 host per channel before seeing major drop in performance – Jimsmithkka – 2010-11-10T12:15:03.403

You need to look for routers with beefier specs, specifically the CPU and memory. That's a good starting point.

For example the WNDR3700 with 680 Mhz Atheros CPU and 64 MB memory:

http://www.smallnetbuilder.com/wireless/wireless-reviews/30925-start-your-buying-netgear-wndr3700-reviewed

Or the Asus RT-N16 which has a 533 Mhz Broadcom CPU and 128 MB memory

http://www.smallnetbuilder.com/wireless/wireless-reviews/31058-asus-rt-n16-gigabit-n-router-reviewed

Both can run DD-WRT (or OpenWRT) which is definitely recommended.

Jeff Atwood

Posted 2010-11-06T01:24:55.167

Reputation: 22 108

If you care about not having to worry about doing what you're going through now again in another 5 years, you might want to consider an open-source (aka. free) firewall OS.

These can provide functionality matching even high end enterprise hardware- on a commodity PC with a NIC & an access point.

Theoretically, even a garage sale desktop computer can do better than these little Tomato routers.

I use Vyatta for routing hi & lo speed SANS through multiple virtualized & physical networks, and am quite happy with it- even without commercial support, which is far beyond my budget.

Of all I sampled prior to making the decision to use it, their configuration was by far the easiest to get the hang of.

And future-proof is nice.

Of course there are others, I tried a half dozen before deciding on Vyatta. You might like another, any will provide at least what you need for this project.

For example SLAX router I think is discontinued now, but was quite lightweight (didn't need big cpu) a couple years ago.

NginUS

Posted 2010-11-06T01:24:55.167

Reputation: 414