The functional address enabled on the NIC for packet reception.
When the underlying driver initializes its NIC, it resets the functional address to zero. NDIS also initializes the packet filter so that a protocol does not receive functional address packets.
To receive a functional address packet, a bound protocol must later set the packet filter to include the NDIS_PACKET_TYPE_FUNCTIONAL flag. At any time, it can disable packet reception by canceling this flag. The order in which the protocol enables reception for functional address packets is unimportant.