Network administrators at the Duke University in North Carolina, have found themselves in serios trouble when they discovered that the university’s wireless networks suddenly started to malfunction.
They started to notice peak CPU utilization on the WLAN controllers as they were struglling to process a large number of ARP request. After further investigation, the network administrator found that it were actually iPhones that were sending up to 18,000 address requests per second, nearly monopolizing the access points’ bandwidth.
“Because of the time of year for us, it’s not a severe problem,” says Kevin Miller, assistant director, communications infrastructure, with Duke’s Office of Information Technology. “But from late August through May, our wireless net is critical. My concern is how many students will be coming back in August with iPhones? It’s a pretty big annoyance, right now, with 20-30 access points signaling they’re down, and then coming back up a few minutes later. But in late August, this would be devastating.”
It looks like the iPhones are causing problems because when they leave the coverage area of their last connected WiFi access point, they try to reconnect to that specific AP thus flooding the network with MAC address requests.
Most of the WLAN at the Duke University is comprised of Cisco thin access points and controllers, but Miller said “I don’t believe it’s a Cisco problem in any way, shape, or form.”
Miller’s team, has informed Apple about this problem, but so far, nothing substantive has been heard from iPhone’s manufacturer.