多项选择题
	A. If a packet is sent to a multicast group address, the multicast frame contains the source multicast address.
	B. A router does not have to be a member of a multicast group to receive multicast data.
	C. A router must be a member of a multicast group to send to the group.
	D. A router does not have to be a member of a multicast group to send to the group.
	E. If a packet is sent to a multicast group address, all members of the multicast group will rece ive it.
	F. A router must be a member of a multicast group to receive multicast data.