Help fix a cafe's wireless setup!

January 3, 2009 2:21 PM

Any advice on setting up a wireless access point for a cafe for a budget of under $200?

I am trying to set up a wireless access point for a cafe. There is likely to be a maximum of 30 users. Here are four options for a set-up given a budget of under $200:

a) consumer wireless router, say the Linksys WRT600N running dd-wrt,

b) 'pro-sumer'/office wireless router like say DLINK 724GU

c) 'pro-sumer' wap like say NETGEAR WAG102 paired with a consumer router to do NAT and minimal firewall

d) 'pro-sumer' wired router ala CISCO SMB RVS4000 paired with a cheap consumer wireless router used as an access point.

The WAN would be a DSL line. This is a free service so nothing is going to be 100%. Right now the cafe is using a consumer dsl-modem/wireless router and it is, not surprisingly, not dealing very well with the load. In particularly it seems like it doesn't like routing that many users, but signal strength is basically fine.

I guess the basic question is whether managing the wireless connections or the routing is the weak point for a cheap setup.

posted by geos to technology (15 comments total)

The ISP provided "router/wireless" dohicky generally sucks. I would do the following as a first step:

1. Disable all routing within the router (litterally.. everything.. make it just a modem)

2. Get a DD-WRT router. I would suggest the granddaddy WRT54GL over something with N personally. Your sharing a tiny pipe; and people will still be using B radios -- so your overall speed will suck even if you have a 10000mbps wireless network.

You shouldn't need a dedicated router for this little traffic (<1>
Anything more, or a "real router" is 99.5% overkill.
posted by SirStan at 2:28 PM on January 3

Once you have DD-WRT, you can see if "routing" is the weak point by looking at the routers CPU uage.

I am downloading Ubuntu over Bittorrent right now, as well as pulling ~600k/s over newsgroups.

System Information
Router
Router Name
DD-WRT
Router Model
Linksys WRT54G/GL/GS

Firmware: DD-WRT v24 RC-6 (01/02/08) std
Time: 23:29:53 up 19 days, 20:46, load average: 0.11, 0.05, 0.00

0.11 isn't REALLY 11% usage.. But its close.
posted by SirStan at 2:30 PM on January 3

the WRT600N has two radios that can operate simultaneously, I thought it might help to have two SSIDs for b/g and a... but this might be too confusing for the users.

You shouldn't need a dedicated router for this little traffic (<1>
Anything more, or a "real router" is 99.5% overkill.

I would have thought this, but the dsl-modem seems to be borking the routing... does the wrt54 really have that much more going for it? i don't think the problem is traffic/cpu so much as the software handling the constant DHCP handshaking and NAT as people enter and exit the network... so maybe that answers the question...dd-wrt!?
posted by geos at 2:38 PM on January 3

The reason these things have two radios is because one radio can only handle about 10 ro 12 simultaneous connections. Usually less when you talking about non-enterprise equipment. So if your requirements are to have 30+ people at the same time and have a usable connection then you'll need two radios, thus the "confusing" two SSIDs. Considering Ive seen the world's most technophobe people be able to figure this out; i wouldn worry about it.

>In particularly it seems like it doesn't like routing that many users, but signal strength is basically fine.

Again, I suspect this is a radio limitation. Regardless of what you choose to do, its very important you find out how many simultaneous connections the radio can handle. Ive seen businesses with 100+ users use a beater consumer router and switch before, so I think you need to work out the wireless issues. You may need to put in two or three access points all spread around the space to cover all the clients. All three should be on different non-overlapping channels.

Another thing to consider is that you may have the lentire neighborhood using this WAP for their personal browsing. At that point you may want to look into putting a RADIUS server and changing the password daily. This might be confusing for the shop owner. An alternative to this is to turn down the power of the wireless interface so that its almost unusable a few feet from outside the shop. Or put in a WPA key and post it on the cash register if you cant get RADIUS in there. That should keep out casual leechers. Or set a timer so that the internet interface shuts off when the store is closed.

Unfortunately, you cant easily block out p2p and bitorrent. I suggest enabling QoS and making all http, http proxy, and https traffic high priority as well as common vpn, voip, ssh, etc ports. This might help if the cafe's customers are all doing p2p and causing these issues, but I find that scenario is pretty rare.

Lastly, the Cisco is nice, but the best router for dd-wrt right now is a buffalo, I dont remember the model, but you can ask at the dd-wrt forums. It has a nice radio and might be a lot cheaper for the shop owner. I'd stay away from linksys because it wont handle that many users. In fact, I would say that no matter what you pick you will require two radios. For under 200 Id probably look at those two or three buffalos or three linksys if you cant find the buffalo. One will act like a router and WAP and the other will just act like a WAP. Connect them with just a cat5 cable.

That said, Id say the cheapest solution is just attach another wireless access point on his setup, give it a different SSID, and let people connect to it, thus distributing the load. Of course this will have to be on a different non-overlapping channel. No need to redo the whole thing. Or give it the same SSID and let the wireless adapters decide which one to pick. Typically, they'll jump to the other once the SNR gets bad.
posted by damn dirty ape at 3:25 PM on January 3

30 is your maximum, but what do you expect the average to be? Try one dd-wrt first, and get another if it can't handle it. And yeah, QoS is a good idea.
posted by qxntpqbbbqxl at 3:52 PM on January 3

Again, I suspect this is a radio limitation. Regardless of what you choose to do, its very important you find out how many simultaneous connections the radio can handle. Ive seen businesses with 100+ users use a beater consumer router and switch before, so I think you need to work out the wireless issues. You may need to put in two or three access points all spread around the space to cover all the clients. All three should be on different non-overlapping channels.

yeah, this was my initial feeling. the buffalo seems scarce unfortunately... would really like to use just one access point but the Netgear (which can handle 128 users) plus router breaks the budget.

actually, i think the wrt600n has six radios: three for 2.4 and three for 5.8 but who knows how many users it's rated for.
posted by geos at 3:57 PM on January 3

Try an Airport Extreme from Apple. Supports up to 50 users, and is a joy to configure and update.

http://www.apple.com/airportextreme/features/frequency.html
posted by avex at 4:00 PM on January 3

I would be very skeptical of the marketing speak here. I doubt you'll get 50 people using it or at the same time in real world conditions. Id first ask on wireless forums, like the dd-wrt forum, for real world experience. There's a difference between "supports up to 50 users" and what it actually does. Linksys makes a similiar claim but I have yet to see more than six to eight laptops actually be able to use one at the same time with anything that remotely comes close to what we call 'use' like heavy http usage, ssh, vpn, rdp, video, etc. From my personal experience setting up WAPs in offices, I assume 10 is the max per radio, regardless of quality, chipset, or brand. For extremely light http requests perhaps 15-20 but even then Ive noticed radios start to fight one another.

127, 50, etc are marketing speak for "The CPU can handle that many, thus we can state that legally in our marketing." The radio in real world conditions? Not so many.
posted by damn dirty ape at 4:21 PM on January 3

Oh, one more thing. If the DSL line, is say, 1.5mbps down and 384up, then thats really not a lot for 30 people. If 30 people make 30 requests at the same time then they are all in contention for that 1.5 down. That 50k each. That's not enough to support streaming video and other bandwidth heavy applications. Although it sounds like you have a wireless limitation at work here, its worth making sure you have enough bandwidth for your customers. For 30 people Id expect a 3mbps or faster line to be optimal.

Another thing to check is to make sure the dhcp leases are very short, like an hour or less. You may be running out of addresses if theyre set to 24 hours and 250 customers walk in that day with laptops, PDAs, etc.
posted by damn dirty ape at 4:26 PM on January 3

software handling the constant DHCP handshaking and NAT as people enter and exit the network

Absolutely not. DHCP handshake is like 2k tops. Your problem is NOT that.

"Apple Airport Extreme"

For the love of god; no. Thats all. They are a waste of money and horrible to work with.

Seriously -- a DD-WRT Linksys WRT54GL can handle this just fine (and routinely does where I eat lunch). Buffalo doesn't sell wireless routers anymore. They were awesome -- but alas -- no more.

but the dsl-modem seems to be borking the routing

Those DSL routers are poo-poo. One user or ten. They are absolute crap. Seriously. I am willing to bet that just disabling its routing capacity and using anything will fix your problem. I've gotten a half dozen of these calls from friends "hai our patrons think our wireless is broken" .. and we replace the crappy Verizon DSL router with a real router, and tada -- no more problems.

"That said, Id say the cheapest solution is just attach another wireless access point on his setup, give it a different SSID, and let people connect to it, thus distributing the load."

That will just compound the shitty router issue. Do not do this.

I would avoid the N radio -- its all marketing speak. A WRT54GL (or any DD-WRT router really) can handle 30 users just fine. I have had really bad experiences with DLink junk personally...

The benefit of DD-WRT is that it is running Linux. It opens up an entire realm of configuration and management possibilities. Linux/iptables is entirely more robust than your off the shelf proprietary firmware.
posted by SirStan at 6:15 PM on January 3

I recant that -- Go with the WRT600N/WRT610N + DD-WRT. They do indeed have physically discrete dual radios. It wont help you much in this scenario -- but it never hurts to have two (especially if one dies).
posted by SirStan at 6:20 PM on January 3

Another option:

Buy two WRT-54GL's .. power them down as low as they will go .. and place one at each end of the building with the same SSID and channel. This will effectively make two networks on the same SSID. If it truely is a "too many people on teh wireless" issue, this will help.

Again -- then you have one for the inevitable time that one craps out.
posted by SirStan at 6:23 PM on January 3

I'm a little over my skis here, but it sounds to me like the wireless capacity of the radio will be meddlesome. If it was me, I'd set up two or three in a mode like this.
posted by gjc at 6:37 PM on January 3

SirStan, wouldn't same SSID but different (nonoverlapping) channels be better? That's how 802.11 was designed to work, at any rate (they all form one ESS with handoff, dunno if it'll do handoffs correctly with dd-wrt, but it probably doesn't need to). A given client will still only be associated with one AP or the other, even if they have the same SSID and channel, so there's no benefit and of course it raises the noise floor for the other half of the room.
posted by hattifattener at 9:17 PM on January 3

Yes, thats how youre supposed to do it: Different channels.

Stan's advice to get a new dsl modem/router can easily be tested if you plug into the wired interface on the router and see if you get the same symtoms. If there are no issues on the wired then it is not a router/modem issue, its a wireless issue.
posted by damn dirty ape at 9:25 PM on January 3