Is there really an iPad interference problem?

A slow, but steadily increasing, trickle of messages on Apple's iPad discussion forums appears to confirm the findings of Princeton University's Network Systems engineers, who dealt this month with a rapid influx of iPads over a concentrated area. What they've been noticing is that Wi-Fi on iPads that are set for dynamic DHCP leases -- assignments of IP addresses to clients for limited time periods -- are failing to renew those leases when time expires, often after just a few hours.

As a result, users' iPads are stuck with the message "Connecting..." and no easy, or apparent, way to renew their network connections. Although Princeton discovered the problem as early as April 4, and Apple forum discussions began April 11, Apple's only suggestion has left some customers struggling.

"Apple iPads began appearing on Princeton University's campus soon after they become available April 3, 2010. On April 4, we observed our first DHCP client malfunction from an iPad. Over the next few days, additional iPads malfunctioned in the same way," reads an ongoing page on the subject from Princeton's Office of Information Technology. "The malfunction we see is that the iPad uses DHCP to obtain a lease, renews the lease zero or more times (as expected), but then continues using the IP address without renewing the lease further. The iPad allows the DHCP lease to expire, but it continues using the IP address after allowing the lease to expire. The incident continues for some time (typically hours); usually it ends when the iPad asks for a new DHCP lease, or the iPad disconnects from the network."


Since the iPad was released, there have been a number of reported cases of weak Wi-Fi connectivity. But these cases don't appear to have a common root, and in some instances, it appears users' wireless routers were at fault, rather than the iPad. Some have suggested -- and one site demonstrated with regard to dropping signals from Netflix -- simply restoring Wi-Fi settings to factory defaults. One Australia-based consultant suggested setting Wi-Fi connectivity to "Auto," and the positive public response made him something of an online hero.

But that's not related to the DHCP lease case, which has a more defined profile. Some forum contributors report their network connectivity is stuck after putting their iPads to sleep for a while. That could be related to the Princeton issue, or it could be related to the cloud of weak Wi-Fi issues. Nonetheless, on April 5, Apple responded to the sleep problem by taking the Netflix route: resetting to default.

And since that time, volunteer supporters have been referring iPad owners with possibly related issues, such as the DHCP lease case, back to the April 5 message: Have you tried resetting to defaults? Other users with home routers have set their routers to static IP addresses, which they report solves the problem.

That doesn't help Princeton, which runs a campus-wide network. As its OIT team explained late last week, it sets up dynamic IP addresses to expire no later than three hours after lease. "Shorter leases allow us to recover unused IP addresses rapidly, in turn permitting us to assign globally-routable IP addresses to clients without requiring Princeton to impose a NAT between wireless clients and the Internet," the team's iPad problem announcement page reads.

It goes on to chide some technology blogs for having reported that Princeton "banned" the use of iPads on campus, when it never did any such thing. The team's later, in-depth explanation suggests that some on the team may resent the implication that Princeton is the one at fault here, at the very least for making an issue out of the "magical" iPad.

"We could choose instead to not take a pro-active stance to these kinds of issues. A more common approach is to ignore the kinds of problems caused by devices using IP addresses not leased to them, allowing such malfunctioning devices to cause sporadic mysterious network problems for customers as their IP addresses are 'stolen.' Sites that use that approach may take action only when a victim of a malfunctioning device chooses to complain. Most victims probably don't complain because these kinds of problems appear random and short-lived to each victim, and often go away when they 'try again.' We feel that the stance we take ultimately benefits our customers, as it results in more reliable network service to the customers. It reduces the frequency that our customers experience network disruptions due to others' malfunctioning devices."

Princeton is not alone in having noticed the issue; a warning about iPad DHCP leasing turned up on this knowledge base page at LSU.

Probably gearing up for a round of "See, I Told You So" with reporters are members of Israel's Ministry of Communications. A few weeks ago, it banned the import of iPads into the country, prior to Apple's commencement of its distribution deal there with premium reseller iDigital. Though it was reported that iPads themselves were banned in Israel, in fact, it was the import of American versions of the device that the Ministry had banned, and then partly restored in an announcement Saturday (PDF available here).

"The scrutiny conducted by the Ministry technical team vis-à-vis Apple's team, International laboratory and European counterparts confirmed that the device which could be operated in various standards will be operated in Israel in accordance to the local standards," reads the Ministry spokesperson's announcement.

But as TG Daily contributor Aharon Etengoff first noted, and Time Magazine later expounded on, iDigital is owned by Nehemia "Chemi" Peres, the son of Israel's prime minister, Shimon Peres -- a fact that was not lost on iPhone customers last year. An Israel-based commenter to the LA Times noted that iDigital had exclusive Israel sales rights to the iPhone, and only began selling it there for the first time in June 2009, well over two years after its worldwide introduction, at essentially full market prices.

That's a total of three iPad interference problems, only one of which may have any real substance to it. That doesn't mean it's not real, though.

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