In OSPF, with Broadcast Multiaccess Topologies (i.e. Ethernet), the Multicast IP addresses are mapped to MAC-level multicast addresses.

This ought to throw a pretty significant wrench into some advertisers' and marketers' plans—if iOS 8 devices broadcast their Wi-Fi probe requests under constantly shifting unique MAC addresses ...

It would probably be impractical to send an Address Resolution Protocol request. ARP would be blocked at the router local to the Web server because it is a broadcast protocol.

Apple's next generation mobile OS doesn't broadcast your MAC address while searching for wi-fi access points. It's a small victory for privacy advocates and a loss for mobile marketers.