Link flap for setting ether/MAC address

[Anish]

Hi all,
Got a very basic question, why physical link is flapped when we set the
address

# dmesg -c
# ifconfig ix1 ether 70:6d:15:1f:12:72
..wait..
# dmesg
ix1: link state changed to DOWN
ix1: link state changed to UP
#

is this a bug or expected behavior? We could update our MAC in next ARP
request without link flap or some other system like switch etc expect the
link flap to update ARP. Is this the behavior for other systems?

Thanks in advance.

-Anish