You may have heard about Princeton have banned the iPad: 'Lay Off the iPad', Princeton University tells students

I wanted to try to explain the issue that Princeton is facing in layman terms and correct impression that today's national news is giving.

PrestoSports intern Nick Heyd uses an iPad

When your device connects to a network, it asks for a seat on the network.  This is done by a DHCP server on the network.  When you are given a seat on the network, you are told how long you can sit in that.

The challenge is that the Internet has a limited number of seats.  This has led to rationing of the seats on the Internet, with most organizations not having as many seats as they would like.

What most organizations do is create a private network.  This private network can have as many seats as your organization needs, and then this private network is connected to the Internet at one seat.  This process of connecting a private network to the Internet is called NAT.

One effect of this is someone on the Internet cannot go directly to your computer, because it does not have a seat on the Internet, but you can reach anything on the Internet.  This is how PrestoSports's office is setup.

What Princeton wants to do is allow everyone to have a seat directly on the Internet.  This means they have to ration people on their network. That means when they assign your device a seat on the Internet, they only let you have it for 1-3 hours.

The problem is that as the iPad and iPhone quickly turn off and on, it is not always honoring this very short seat assigning.  The result is that the device will start using a seat that is now in use by someone else.  Both the iPad and the other device will experience weird intermittent issues until one of them go back to the DHCP server to get a new seat assignment.

What Princeton has then done is track which specific iPad devices are the most common culprits, which is about 20% of the devices on campus.  Because it is a certain usage pattern of not walking around and turning your device on and off, Princeton can track which people are using their device to trigger the bad behavior, and block those people.

Princeton has written on the behavior that can trigger the problem.

The issues George Washington University are facing are completely unrelated to the issues Princeton is facing.  This is simply a question of the authentication George Washington requires to join their network is not supported by the iPad.  George Washington's staff took no action against the iPad.