[98091] in North American Network Operators' Group
Re: iPhone and Network Disruptions ...
daemon@ATHENA.MIT.EDU (Iljitsch van Beijnum)
Tue Jul 24 18:24:10 2007
In-Reply-To: <46A6609C.8070505@hawaii.edu>
Cc: North American Network Operators Group <Nanog@merit.edu>
From: Iljitsch van Beijnum <iljitsch@muada.com>
Date: Tue, 24 Jul 2007 16:34:32 -0500
To: "Prof. Robert Mathews (OSIA)" <mathews@hawaii.edu>
Errors-To: owner-nanog@merit.edu
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.
