On 24-jul-2007, at 15:27, Prof. Robert Mathews (OSIA) wrote:
Looking at this issue with an 'interoperability lens,' I remain
puzzled by a personal observation that at least in the publicized
case of Duke University's Wi-Fi net being effected, the "ARP
storms" did not negatively impact network operations UNTIL the
presence of iPhones on campus. The nagging point in my mind
therefore, is: why have other Wi-Fi devices (laptops, HPCs/PDAs,
Smartphones etc.,) NOT caused the 'type' of ARP flooding, which was
made visible in Duke's Wi-Fi environment?
Reading the Cisco document the conclusion seems obvious: the iPhone
implements RFC 4436 unicast ARP packets which cause the problem.
I don't have an iPhone on hand to test this and make sure, though.
The difference between an iPhone and other devices (running Mac OS
X?) that do the same thing would be that an iPhone is online while
the user moves around, while laptops are generally put to sleep prior
to moving around.
