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Very BUSY Coffee Shop Wireless Access

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SyscomDT

New Around Here
Hello,
I have configured a few access point at a local coffee shop that seems to be constantly experincing connection issues. We are having problems with clients connections bouncing from one AP to the next, without successful connections, or simply unable to connect to any of the AP's. There are several other AP's in the area on varying channels.

Below are the Devices currently being utilized in the coffee shop:
1. Motorola 3347 DSL Modem
-AP on Channel 11
-Acting as Gateway, Router, NAT

2. Linksys WRT54GL using latest DD-WRT
-AP on Channel 1
-Acting as DHCP Server, Switch

3. Netgear WG302 with latest Firmware
-AP on Channel 6

*All Wireless AP's have Open unencrypted Networks with different SSID's.
*Device 3 is connected to device 2 via Cat5e
*Device 2 is connected to device 1 via Cat5e
*Atleast 150 different devices connect to these AP's per day

Device 1 and 2 are about 1 foot apart (should I change this?)
Device 3 is 50 feet away.

I've had to reset the devices many times to get things working again. It seems that the DHCP Server is running out of IP's, but I have it set to only a 90 minute lease time.

Question 1: Any immediate suggestions?
Question 2: Can I use a much lower DHCP time without connection issues on the client end?
Question 3: Is there a problem with having two AP's close together on seperated channels?
Question 4: If you were to set this up optimally, would you replace a device with one that can handle more connections(All access is wireless)?


Thanks in advance for any and all help!
Regards,
-Scott
 
Below are the Devices currently being utilized in the coffee shop:
1. Motorola 3347 DSL Modem
-AP on Channel 11
-Acting as Gateway, Router, NAT
Why isn't this also acting as DHCP server?

*All Wireless AP's have Open unencrypted Networks with different SSID's.
Have you tried setting all to same SSID?

Device 1 and 2 are about 1 foot apart (should I change this?)
Yes, definitely. The best setup would be to have the three APs spaced as equally as you can in the area to be covered.

Question 2: Can I use a much lower DHCP time without connection issues on the client end?
Perhaps. At worst the client would just have renew the lease, which it should do automatically. But the problem sounds more like that the DHCP server may not be terminating the lease properly. Only thing to do if that is the case is to try a different DHCP server.

Question 3: Is there a problem with having two AP's close together on seperated channels?
Yes, you could be overloading the receivers and reducing throughput.

Question 4: If you were to set this up optimally, would you replace a device with one that can handle more connections(All access is wireless)?
This is probably part of your problem. Consumer routers generally don't spec the number of simultaneous clients supported. It's unlikely that 256 clients are supported, however. The # is more like 16 or 32. Trying to get around that by using more than one AP may not work because you can't guarantee that clients attach to the APs evenly.
 
The Motorolas are actually combo modem/routers..so they do NAT already. I prefer to have my primary router (which will be of better quality/performance/stability) do the PPPoE login, NATing, DHCP, and be the one and only gateway, so I always disable the NAT/router feature of the DSL ISP supplied gateway device.

I'd then configure your wrt54gl to be your router, and access point. Could probably ditch the Netgear. Pickup a pair of extra long 9 hi gain antennas for your wrt...about 35 bucks for a pair.

Log into DD web admin and punch the output power up to 85.

I don't envision a coffee shop as being large enough to warrant more than 1x good access point for coverage. How large is your shop? Walls?

How many people do you have using the wireless at once? (say peak usage) I know you mentioned 150 per day...but how many "at once"...what's your max amount of clients at one time?

I've found that those wrt54gl models running DD are quite stable, Tomato is another great firmware for them. I actually use the gl models frequently for the budget wireless setups I'll do for people. Matter of fact, just this week I'm finishing up a budget project for a small nursing home...there's no way they can swing a full business grade setup like Aruba or HP ProCurve wireless..which would run 14K and 8K respectively...but this week I'm finishing up installing a pretty decent "budget" setup for them...using 10x of the wrt54gl models, each with a pair of those long hi gain antennas, 1/2 of them fed by Linksys PoE injectors, all flashed with DD-WRT and running in access point mode.

But as Tim mentioned above...I guess depending on your answer to "total amount of concurrent users"....if you really are up above 100 people online with wireless at the same time, there's no way consumer grade models will keep up with you.

May consider stepping up to something like PepWave
http://www.pepwave.com/products/officepoint/

Or, DLink has a pretty decent setup I've done a few times....a WebSmart managed switch (DES-1228P) that provides PoE power to their "thin" access points (DWL-3140AP), which are about the size of small smoke detectors, put them in the ceiling, and they're actually managed from the switch. Each one of those is rated for up to 96 clients. Sprinkle 3 of those around the ceiling of your coffee shop. They do "load balancing".
 
Last edited:
Hey, Thanks for your very detailed information guys!
I've Tried the additional AP's for load balancing, but as thiggins mentioned, ther is no way to assure people evenly connect to AP's.

*Would the having all the AP's on the Same SSID cause everyone to automatically connect to the AP with the strongest signal?

The shop is a long (maybe 150-175feet) and narrow (maybe 40-50 feet across). Thus the reasoning for two AP's (initially) the WG302 in the front, and the orginal Actiontec DSL Modem/Router (this was replaced, due to consistent conection problems with the business grade Motorola).
We setup the DD-WRT as the DHCP Server becaus it provided more granular control of the DHCP settings. *Should I use the DNSMasq DHCP Server, or the DD-WRT DHCP? We have always had issues with the leases, even with the very short lease time.
I originally ran the DHCP on the Motorola and it simply would not release the IP's quick enough, so I had to try something else.

A question in regards to DHCP... *If the lease expires for a client that is still connected, does the client seamlessly renew it's lease for that same IP without the end user knowing?

I would say peak usage is around 50 users, and sometimes it is steady all day at those numbers.

I like the idea of the D-Link Thin AP's, but it does not resolve my DHCP issue that I think is currently causing alot of the connection problems. *Does the DD-WRT have a log that I can look at to maybe see why it is running out of IP's?


Thanks again fellas!
-Scott
 
*Would the having all the AP's on the Same SSID cause everyone to automatically connect to the AP with the strongest signal?
In theory, yes, but eventually it all depends on the roaming logic and roaming aggressiveness of the end client. (basically it should, but some crappy devices dont).

*Should I use the DNSMasq DHCP Server, or the DD-WRT DHCP?
I think you should use a PC based router to do your dhcp and routing, such as pfSense, M0n0wall, or Untangle. I get the feeling you may be having an ARP problem on your router.

A question in regards to DHCP... *If the lease expires for a client that is still connected, does the client seamlessly renew it's lease for that same IP without the end user knowing?
If everything is working properly, yes. The computer knows when it's lease is expiring and will attempt to renew the same lease if it is still on the network. This is transparent to the end user, unless your DHCP server is having problems or really slow.

I like the idea of the D-Link Thin AP's, but it does not resolve my DHCP issue that I think is currently causing alot of the connection problems. *Does the DD-WRT have a log that I can look at to maybe see why it is running out of IP's?
Another idea is to switch to a larger subnet (supernetting) so a /23 (255.255.254.0) or a /22 (255.255.252.0) would give you 512 or 1024 ip addresses to work with, and a lot more headroom.
 
Thanks for all of your info! Sorry, I've been caught up on other projects.
I think I will take your suggestion and setup an Untangle Firewall that will handle the DHCP and DNS more reliably. I'll get back to this forum after I've had a chance to set it up.
Regards,
-Scott
 

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