On Jul 24, 2007, at 5:34 PM, Iljitsch van Beijnum wrote:
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.
But I know that I have walked around IETF meetings with my laptop open, and I know others do too, and I don't recall ever hearing about this problem at an IETF meeting from Jim Martin and the other NOC volunteers. Regards Marshall