One week after discovering a glitch between Apple iPhones and its Cisco-based campus wireless network, Duke University on July 20 finally got to the bottom of the problem that caused periodic outages of the Wi-Fi network.
Initial reports of the problem placed the blame for the outages squarely on Apples iPhones, which flooded the Cisco WAPs (Wireless Access Points) with thousands of address requests per second. However, in a statement released this afternoon, Cisco Systems admitted that the problem was caused by a Cisco glitch.
"Cisco has provided a fix that has been applied to Dukes network and the problem has not occurred since," the statement read. Cisco did not describe what the source of the problem was. Late on June 20, Duke released a statement elaborating on the problem and how it was resolved. "The reality is that a particular set of conditions made the Duke wireless network experience some minor and temporary disruptions in service," said Tracy Futhey, the universitys chief information officer, in a statement. "Those conditions involve our deployment of a very large Cisco-based wireless network that supports multiple network protocols. Cisco worked closely with Duke and Apple to identify the source of this problem, which was caused by a Cisco-based network issue," the statement said.
"Cisco has provided a fix that has been applied to Dukes network and there have been no recurrences of the problem since," the statement said. "We are working diligently to fully characterize the issue and will have additional information as soon as possible," the statement concluded.
The problem first surfaced late last week, according to a statement from Duke on its Web site, and it reportedly affected some 20 to 30 WAPs which would go out of service for minutes at a time as a result of the address request flooding.
In the statement, Duke officials played down the extent of the problem. "Each event lasted no longer than 10 minutes and most users would have noticed no difference in their wireless service, though disruptions may have caused access delays or sluggish Internet performance for isolated users," the statement said.
News reports the week of July 16 suggested that the iPhones flooded the WAPs with as many as 18,000 address requests per second, causing them to go out of service for as long as 10 to 15 minutes.
Apple officials would not comment on the cause of the problem but said in an earlier statement that the company is "working together with Duke and Cisco to resolve this as quickly as possible."
The problem could be particular to Duke. Other large universities—specifically the University of Wisconsin at Madison—have not experienced problems with its registered iPhones and Cisco-based Wi-Fi network, according to Dave Schroeder, an administrator in UWs Division of Information Technology.
"We have seen upwards of 120 unique iPhones since June 30 on our campus-wide wireless infrastructure, which also uses Cisco 802.11b/g access points. To date, we have not encountered or detected any undesirable behavior from iPhones," said Schroeder. "As I have also not heard reports of errant 802.11 iPhone behavior from any other institution or site, it appears that the issue at Duke may be unique. There may be something unique to Dukes particular wireless installation configuration that the iPhone may be exposing," he added.
One analyst who follows Apple speculated that Dukes network requires encryption that the iPhone doesnt have.
"My suspicion is that Dukes network requires Ciscos (Lightweight Extensible Authentication Protocol) security encryption and the iPhone doesnt have that incorporated into it. That could be a source of the problem," said Van Baker, a research vice president at Gartner in San Jose, Calif.
"Ciscos LEAP is an enterprise deployment not seen in the consumer market at all. The iPhone doesnt have a lot of the features youd normally expect to see in an enterprise class phone," he added.