Tuesday, July 11, 2006

Why Does WiFi have Ad Hoc mode?

I am at the 66th IETF and so it is time to ask 'why does WiFi have ad hoc mode?'

As near as I can make out the only use for ad hoc mode in WiFi is to provide a ready means of performing a denial of service attack. If you have a lot of laptops in a small space together running off a common access point (or two) they usually get along pretty well. If you have someone running in ad hoc mode they are chewing up as much bandwidth as the access point.

So the usual pattern at these events is the room fills up, the network gets a little slow. At some point some dweeb decides for whatever reason that the speed of the network is intollerably slow. They start fiddling with their network settings trying to make the thing faster. At some point they ask 'what does ad hoc mode do'. They try it out and in the process cause some folk to loose their connection to the access point.

So then they start to fiddle and they see the ad hoc network being advertised 'what is this' they ask and they try to connect. So now we have two ad hoc networks, then three and four. And each time more of the bandwidth gets gobbled up and more people start to fiddle and the situation gets worse.

Eventually the point is reached when the meeting chair has to ask people to shut down their computers if they are using ad hoc mode before the sheer volume of microwave radiation in the concentrated space starts to slowly cook people from the inside out.

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