Problem
1. Why do you think both the sender and receiver addresses are needed in the Internet?
2. Why do you think there is a need for four levels of addresses in the Internet, but only one level of addresses (telephone numbers) in a telephone network?
3. Domain Name System or DNS is an application program in the TCP/IP protocol suite. Research and find the equivalent of this protocol (if any) in the OSI model. Compare and contrast the two.