Suppose host A is sending to a multicast group; the recipients are leaf nodes of a tree rooted at A with depth N and with each non leaf node having k children; there are thus k N recipients.
(a) How many individual link transmissions are involved if A sends a multicast message to all recipients?
(b) How many individual link transmissions are involved if A sends unicast messages to each individual recipient?
(c) Suppose A sends to all recipients, but some messages are lost and retransmission is necessary. Unicast retransmissions to what fraction of the recipients is equivalent, in terms of individual link transmissions, to a multicast retransmission to all recipients?