Wireless Routers for Congested Areas?

An anonymous reader asks: "I have been living close to campus at UW Madison for the past six months or so and have come across a problem. We, along with everyone else in the area, have a wireless router, both a Belkin 54g and a Linksys WRT54G. We have Charter 3 Mbit down/.25 Mbit up cable and 6 guys in our apartment. Just on our block about 15-20 people have routers. We are constantly plagued with problems connecting to the wireless, staying connected, getting connected after rebooting, hibernating, and so forth. We have to reset the cable modem and the router many times a day to get everything rolling again. I am thinking that the router is the problem, because my dad always told me that's why they have twenty dollar routers up to thirty thousand dollar routers. What router can I purchase that will help my situation and will work well in a congested college area?"

Comments

kismet

[Gothmolly]

Easy, snarf your neighbor's wireless connection, and dump your router entirely.

Anything that runs dd-wrt

[lavid]

You can boost the signal strength on routers once they're flashed with DDWRT. Do that (up to like 80mW) and use the least used channel and you should be good.

Re:Anything that runs dd-wrt

[LoRdTAW]

To better understand the grandparent with respect to antenna gain and maximum power dissipation, here is a little analogy:

The maximum power for the 2.4GHz 802.11x is 100mW. Antennas are usually compared to a reference point which usually is a 1/4 wave dipole antenna. So think of it in terms of compact fluorescent and incandescent light bulbs. A 100 watt Incandescent give you a mix of light and heat which is very inefficient (1/4 wave dipole). A compact florescent can give you 400 watts worth of light with the same amount of power the 100 watt incandescent uses (high gain antenna). so a 100W incandescent would nicely illuminate your own driveway but a C.F. lamp would flood the area with light annoying your neighbors while consuming the same amount of power. The power consumption is the same between the two lamps but their ability to radiate that power into light varies greatly. Same applies to antenna design.

Now the reason crappy low gain dipole antennas are used is this, you want to keep interference down so you use a crappy antenna that has little chance of picking up your neighbor's wireless router or microwave. BUT the transceiver has enough transmission power (100mW) to get a decent signal out of that crappy antenna to your clients and vice versa. A 100mW transceiver with a high gain omni directional would not only open your network up to interference from other 2.4GHz devices but you would flood a wider radius with your RF power interfering with other wireless systems. So its legal to get the power to 100mW but only with the crappy dipole. If you used a 3dBi omni @ 100mW it would be comparible to pumping 200mW into the dipole which is illegal. So while it sounds enticing to use high gain antennas on both the clients and AP, its going to cause only more headaches for your network and the networks that surround you.

Hopefully I have explained this properly as its been a while since RF/communications class.

Asus

[micksam7]

I've been using a D-Link 524 router for a while in my home setup. It's given me nothing but trouble, rebooting and randomly blocking computers on the network [part of it's built-in security junk, it's blocking logs show it will block perfectly valid computers for random reasons]. Firmware updates don't seem to fix it.

I got tired of that and searched for a router capable of running OpenWRT in case the default firmware sucked.

I found the Asus WL-500g Premium and bought that for about $100 at the time. The default firmware worked fine, but I decided to try openWRT, then tossed that in favor of X-Wrt which had a better web interface.

The router's current uptime is 37 days with no crashes or any oddities what so ever. Last restart was for a firmware reflash.

As for reception, try lesser-used channels. 6 is a really common channel, so try 1 or 11 instead [or any other channel].

Note however, that if you go the path of openWRT or X-wrt, you're going to have to spend some time working out the kinks at first. Mine worked fine, except wifi couldn't access wan, which took a bit to figure out how to fix it; openWRT's wiki and forum were a big help in figuring out that.

Change your firmware on the Linksys...

[Fallen Kell]

Check what version of the WRT54G that you have. You should be able to run "DD-WRT" on it. This read up on doing the flash properly as you can nuke your router if you put the wrong image on first. Basically there is a "first time flash" image to use. And then once you have put that on it, you can flash to the full version that your router supports. Again, it will depend on which hardware version of the WRT54G you have as there are something like 6 different revisions, some more powerful then others and some more friendly for using third-party images (due to having more storage on the device, some have as little as 2MB total space for the OS, others can have as much as 16 or even 32MB of space).

Now, once you have flashed it, you can use additional channel space that is normally unavailable to use as it is reserved bandwidth. I forget which channel ID it is, channel 14 I think is not normally accessible in the USA. Change to that channel and most of your interference should go away from other competing devices.

Now, other things to do, turn off the broadcast SSID. Setup the MAC Address Filter and only include the MAC addresses of devices that you want to allow to connect. You can now even setup your own local DNS and statically assigned DHCP addresses for devices (in other words, your device still does the normal DHCP request, but you always get the a specified address for that device, useful if you have any kind of file sharing or network server).

Other things you can do is boost your antenna gain in the software if you have poor coverage in the house/apartment. You can also try specifying a specific antenna to transmit or receive, which can be useful if you want to upgrade an antenna with one of your own design, or something you purchased. I personally have a 16 dbi omni on my wireless router. I also have a 24 dbi directional in case I ever need to do something like making a wireless bridge. Using something like that could potentially let you connect to your campus's wireless net and use their higher speed pipe that your student fees already pay for.

Re:Sommoderators will moderate anything up, it see

[BeBoxer]

7 8 9 -- all of those will suffer from the same problems from people on channel 6. 802.11[bg] is not designed to work well and play with others.

Actually, you will see worse problems. 802.11 is in fact designed to work well with overlapping networks. Devices on overlapping networks will watch all the packets in the air on the same channel, including those on other networks. They will backoff when they see other devices sending packets. You can still get bad congestion of course, but the devices are at least trying to play nice.

If you switch to a neighboring channel, like 5 or 7, then the devices can't play nice any more. Instead of being able to hear and understand the traffic on other networks, it all just shows up as big blasts of noise. I actually did a bunch of testing of this years ago. If I put two AP's on channel 1 right next to each other and ran simultaneous transfers with two clients, the aggregate bandwidth was about 95% what I would get with two clients on 1 AP. But when I moved one AP to channel 2, it dropped to 75%-85%. At channels 1 and 3, it dropped into the 70%--75% range. After that, it climbed, getting back to just over 100% at channels 1 and 5. Channels 1-6 got me up to 180% of the original throughput and 1-7 up to 210% of the original. In retrospect, I had the AP's way too close which explains why I still saw interference at the 1-6 step. But assuming your neighbors aren't putting their access point 2 feet away from your own, this shouldn't be an issue.

So what's my point in all this? Stick to 1, 6 and 11 for everybodies sake. I have actually heard of some sites using four channels with, I guess, three channels of separation. So 1,4,7,10 for example. I haven't testing this and I'm not convinced it's really any better. Because the performance at three channels is about the same or a little worse than the same channel. It only starts to get better at four channels of separation, but then you have to use 1,5,9,13 and channels 12 and 13 aren't permitted by the FCC.