iPhone and Network Disruptions ...

Wed Jul 25 00:00:25 UTC 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.

Regards
Marshall