Problem 3:

(i) Draw the protocol stack (layers) of the Internet. Write down the key functions of each layer. When you need to build a network of two devices that are directly connected through wireless, which of the above layers will you need to implement? Draw the protocol stack for this network.

(ii) Differentiate between message, segment, datagram, and frame.

(iii) Alice wants to transfer a message to Bob through a small network that implements only application layer, transport layer, link layer, and physical layer (i.e. the network layer is missing). But Alices computer is not directly connected to Bobs computer. Hence, her message has to go through multiple hops (i.e. through multiple other computers). Explain how this may work.

(iv) Now suppose a network implements only application layer, network layer, link layer, and physical layer (i.e. the transport layer is missing), but needs to support file transfer, video streaming, message transfer, and email. What can be the possible adversities?