Simple approach: One process scatters the N messages to the other processes, one at a time.

Amount of data transferred: (N-1)*p

N = number of processes
p = size of message
Number of steps: N-1

Smarter approach: Let other processes help propagate the message. In the first step, process 1 sends half of the data (size 4*p) to process 2. In the second step, both processes can now participate: process 1 sends one half of the data it received in step 1 (size 2*p) to process 3, while process 2 sends one half of the data it received in step 1 to process 4. At the third step, four processes (1, 3, 2, and 4) are sending the final messages (size p) to the remaining four processes (5, 6, 7, and 8).