Princeton Finds Cause of iPad Wi-Fi Woes

Almost from the day the iPad reached the anxious hands of early adopters, there have been reports of intermittent and unsteady Wi-Fi connectivity. This problem surfaced on the campus of Princeton University as well, and the school's IT department says it has gotten to the bottom of the problem.

The Wi-Fi support has been one of the most common complaints about Apple's (NASDAQ: AAPL) hot new tablet PC. Users report that they can stand right next to a wireless router and watch the signal strength yo-yo even though the device is right next to the router and not being physically moved.

Among those affected were students at Princeton University. The school's Office of Information Technology (OIT) noticed that iPads were causing problems on its network almost from day one and began running tests to try and determine the cause.

The engineers found that the problem, at least in part, is how the iPad handles DHCP (define) leases. DHCP, which stands for Dynamic Host Configuration Protocol, is responsible for assigning IP addresses to computers on a local network. Normally, wireless devices don't have assigned IP addresses but are assigned and released dynamically as needed.

Even when an IP address is assigned to a device, it has to be renewed at regular intervals. If the device doesn't request a renewal of the address, the DHCP server will consider it freed up and assign it to another device.

The Princeton team found that under certain circumstances, the iPads allow the lease to expire but continued to try working with the same IP address that the network now thought had been surrendered. The problem the Princeton team said it saw was that the iPad kept trying to use the IP address that had been surrendered for hours, and the school's own security system had to kick in and block the device.

As of April 15, 22 of the 41 iPads on the campus network have shown this problem. Some have malfunctioned several times and eight devices have been blocked from the school's network.

Is It the Mobile Device's Operating System?

"Within a few days, we had seen enough incidents from the iPads already on campus to conclude that there was a problem. Roughly half the iPads had malfunctioned in the same way; the symptoms all matched the description above. Because the problems were so common and began as soon as the iPads arrived, we felt it unlikely that the problem was due to customer misconfiguration. It seemed more likely to be an issue common to the iPad/iPhone OS 3.2 platform," said a report from the OIT group.

In the mean time, the campus has issued a warning to students not to use their iPad due to the DHCP problem until it is fixed, and said if they do use the Apple device, they risk being blocked from the school's network.

Workarounds currently include performing a full power cycle by shutting the iPad down completely, turning the wireless off and then on again in the tablet’s settings, or in some cases just moving out of the Wi-Fi router’s range and then back into it again.

Princeton's OIT report said it has contacted Apple. Neither Apple nor Princeton responded to InternetNews.com's request for comment by press time.

Andy Patrizio is a senior editor at InternetNews.com, the news service of Internet.com, the network for technology professionals.


iPad, Apple, Wi-Fi, mobile device, Princeton University