ABEC Pty Ltd (a public company) has been granted a block of addresses starting with the address 172.154.60.0/24. a)Calculate the total number of addresses in this block. Show your calculation (1 mark)b)The company has decided to distribute the addresses on a departmental basis, with Dept#1 requesting 120 addresses, Dept#2 requiring 60 addresses, Dept#3 needing 30 addresses and Dept#4 wanting 12 addresses. Create the 4 subnets for the company. For each subnet, list the subblock address along with its subnet mask in CIDR format. Show your calculations for all subnets. (1 mark for each correct subnet)c)How many addresses are left unallocated? Show your calculation. (1 mark)Question 3 – Fragmentation (4 marks)An Ethernet packet 1,500 bytes long arrives at a router, which determines that the next destination is an X.25 network. Do the following, being sure to show your calculations and explain your reasons.a)Assuming that the router decides to fragment the packet into 3 fragments, determine the size of each fragment, and identify their starting byte and end byte. (2.5 marks)b)Calculate the fragmentation offset for each fragment. (1 mark)c)Under what specific condition would the router decide not to fragment the packet and in that case how would the packet be treated? Be as precise as possible in your answer (.5 mark)Question 4 – Advanced routing study (15 marks)Research and review appropriate materials, including the textbook, and answer the first two questions (a & b).a)Define the terms and discuss the relationship between Autonomous Systems, Inter-domain routing, and Intra-domain routing. (2 marks)b)Identify the major routing protocols associated with Inter-domain and Intra-domain routing and list their similarities and differences (1.5 marks). Finish by commenting on why we need different protocols for Inter-domain and Intra-domain routing. (1.5 marks)Study the two articles listed below – both are freely available on the Internet. You may use other references in addition to these, as needed. Then answer the remaining 3 questions (c, d & e). cBriefly summarize in your own words the problems with current routing methods that the authors have identified. (5 marks)d)Contrast and compare the concepts of embedded routing and extensible routing. (2.5 marks)e)How does the proposal of Routing As A Service (RAAS or just RAS) address the problems with current routing methods? (2.5 marks)