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Re: iPhone and Network Disruptions ...
- From: Marshall Eubanks
- Date: Tue Jul 24 21:42:05 2007
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.