Problem: Five prisoners are locked up in adjacent cells in a prison. They would like to communicate with each other but the walls and doors are too thick. One day, one of the prisoners discovers that if he hits the water pipe in his cell with a metal spoon, the sound travels to two cells in each direction, i.e. the sound from cell i can be heard in cells i-2, i- 1, i+1, and i+2, assuming these cells exist. After some experiments, the prisoners discover this is true for all the cells. Over lunch, they decide to define a protocol that will allow efficient communication. One of the prisoners took a data communications and networks course in the past and argues that this is very much like an Ethernet so they decide to use the Ethernet protocol over their Water Pipe Network (WPN). The prisoners planning the break are in five adjacent cells that are lined up in a row. Unfortunately, there are some problems. Can you help them by answering the following questions? Question: In the WPN network, not all cells can hear each other. What mechanism could you use so all inmates can talk to each other?