Windows Networking/Wifi interference


Dear Michael,

There is something that bothers me about wifi and that is interference. I think there is a solution for this but I am not sure though. Could you please tell me if I am right or wrong?

I have 20 wifi networks on range right now, most of them with zero or just one user connected to it. Some are 802.11n, some are 802.11g; some are in channel 1, others in 6 and others in 11.

Now picture this scenario that I faced when trying to install a new router at my friend's house: We bought a 802.11n router but we could not use 5GHz because his notebook does not support that. So we used 2.4GHz and we would get 128Kbps download/upload speeds. I decided to use 802.11g instead (as I understand it, it uses a narrower bandwidth so there is less possibility of interference). I used kismet to see how many networks were using channel 1, 6 and 11 and then set the router to the least used channel. Now my friend's internet speed is limited by the isp as it should and the file transfer speed between computers in the network is limited by the 802.11g protocol and interference.

I am not happy about all this. What's the use of the new protocol if it can only be used in Antarctica or the middle of the ocean?

One solution is to migrate to 5GHz, but how long until everybody does that and we are back at the beginning?

My question is this: Suppose there is only one wifi network per isp (there are at most two isp's in each city), would that solve the problem?

In other words, would the interference be relieved by having only one network? I know there will be interference because there are multiple computers connected to the network. But would it be less than in the multiple networks scenario?



Having a large number of different wifi routers in a small area can lead to interference and reduced performance.  Having a single or small number of wifi sources would certainly make things go better, but I think the genie is out of the bottle on that one.  You cannot prevent people from having private wifi routers in their homes, something many people would continue to have even if ISPs directly provided a wifi connection for everyone to use.  The private home wifi gives the ability to transfer data within your own local network without involving the ISP.  That is certainly not something I would want to give up.

In addition to other routers, other electronic devices including wireless phones, baby monitors, bluetooth devices, even microwave ovens, can interfere with a wifi signal.  So you may have issues beyond just the other wifi devices in your area.

My number one suggestion to improve performance would be to get a dual band router like the Linksys e2500, but that's not going to help you much if you have to connect older legacy devices that cannot make use of the 5 GHz.  It might also help to use WPA encryption rather than WEP.  But again, that depends if the older network card will support it.

There are things in the works that will make the 802.11n technology obsolete in a few years.  The newer 802.11ab is going to increase both speed and range. We may also see a better metro wireless system as ISPs move into the bandwidth once used by analog TV channels, allowing the to greatly increase wifi ranges.  Once that happens, you may see less need for individual wifi routers in heavily populated areas.  But those are things we need to wait for large companies to do, not something we can do ourselves.

I hope this helps!
- Mike  

Windows Networking

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Michael Troy


I have a fair amount of experience in peer-to-peer networking. I can answer questions about hardware, networking software, protocol settings, etc. I have some client-server experience, but not a lot with Windows-based servers. I can also give some advice on home network security: VPN, firewalls, anti-virus, etc.


I am the Director of Information Systems for a large law firm which connects about 300 users over five offices via a wide area network. We use client-server, peer-to-peer, remote access, VPN, Internet, and proxy servers.

I also have a peer-to-peer network of computers at home, with file and print sharing, remote access, shared network storage, and shared Internet access with a firewall.

BA George Washington University JD University of Michigan

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