Problem 4. Steps of a communication process are shown in the following diagram. a) What are the function and purpose of this protocol? b) Describe the function of each message noted in the diagram. c) Briefly explain the data fields of each message. Label and describe the function of unlabeled boxes in this diagram. d) What are the drawbacks in this process, if any? User IDC || ID tgs (1) (AS) TGT =EK [Ticket tgs] (2) IDC || IDV || Ticket tgs (3) Client Workstation Ticket Granting Server (V) Server (TGS) (C) Ticket v (4) IDC || Ticket v (5)