'Returns corresponding multicast EthAddr
Assumes this is, in fact, a multicast IP address!'

@property
def multicast_ethernet_address(self):

    if (not self.is_multicast):
        raise RuntimeError('No    multicast    EthAddr    for    non-multicast    IPAddr!')
    n = (self.toUnsigned(networkOrder=False) & 8388607)
    return EthAddr(('01005e' + ('%06x' % n)))
