-------------------------------------------------------------------
Mohamed G. Gouda					CS 356
Spring 2018						Exercise 9
-------------------------------------------------------------------

Let (N, E) be a broadcast network whose graph is a tree, and let n
be the number of nodes in network (N, E). Also let (u, seq) denote
a bradcast message that is generated and sent in network (N E).
How many copies of message (u, seq) are sent in network (N, E)?
Explain your answer.

------------------------------------------------------------------
Solution
------------------------------------------------------------------

Because the topology of network (N, E) is a tree, node u that 
genrated message (u, seq) receives no copy of the message. Also 
every other node in the network receives only one copy of the
message. 

Thus, the number of copies of message (u, seq) that are received
in the network is (n-1), where n is the number of nodes in the
network. Therefore, the number of copies of message (u, seq) 
that are sent in the network is (n-1), where n is the number of 
nodes in network (N, E).