Problem 3: Distributed Systems-Anatomy Study Internet by itself is among the largest distributed systems ever built by human being. Now lets gain some insights about its design philosophy in order to handle similar challenges for any distributed system as listed in the Textbook, such as heterogeneity, openness, security, scalability, and so on. (a) IP functionalities The network layer protocol for the Internet is IP protocol; and it is an example of using a spanning layer in distributed system design. Briefly explain the benefits of using this IP spanning layer in the Internet. (b) Architectural Model of D.S. World Wide Web (WWW) services make use of the client/server architecture. One of the main reasons for using this architecture is to enabling effective resource sharing. What resources can be shared in WWW? Please use an example to demonstrate the benefit of client/server model in supporting effective resource sharing. (c) Failure Tolerance Domain name server is critical to the correct operating of Internet by providing the translation between human readable hostnames to machine readable IP addresses. However, some Domain Name Server may go out of service due to, e.g., maintenance. Why can Internet keep functioning without them? Briefly explain your answer.