Assessment Task 1 Task 1: Link Layer (and network layer) addressing and forwarding a) Consider the figures below. The IP and MAC addresses are shown for nodes A, B, C and D, as well as for the router's interfaces. F9-F1-AC-B7-98-Co 128. 119, 163, 115 B8-B2-OC-20-1E-13 128,119,163.157 40-DB-CC-48-65-F2 128.119.71.107 B 80-FC-4C-42-B8-BF 128, 119.89.37 (6) C (3) (1) (5) A BE-8C-90-7C-03-FD 128,119.71.222 E8-88-72-78-04-44 128.119.71.219 BD-AD-C5-46-6E-E1 128, 119,89,19 Figure 1 Consider an IP datagram being sent from node A to node B. Give the source and destination Ethernet addresses, as well as the source and destination addresses of the IP datagram encapsulated within the Ethernet frame at points (1), (2), and (3) in the figure above. F1-28-CC-60-52-FD 128.119.147.246 91-67-63-F8-62-07 128,119,147.240 A8-7A-25-13-CA-BB 128.119.30.147 M B 4D-72-32-70-7F-78 128.119.50.157 (6) (3) (2) A (4) D 9D-71-78-7F-EB-E6 128.119.30.25 69-A5-88-81-84-88 128.119.30.170 BA-D4-9C-F7-09-07 128.119.50.130 Figure 2 Consider an IP datagram being sent from node B to node C. Give the source and destination Ethernet addresses, as well as the source and destination addresses of the IP datagram encapsulated within the Ethernet frame at points (1), (3),(4), and (6) in the figure above. Task 2: Error Detection and Correction: Cyclic Redundancy Check Consider the Cyclic Redundancy Check (CRC) example shown in your lecture. Suppose that the 4-bit generator (G) is 1001, that the data payload (D) is 10011111 and that r=3. a) What are the CRC bits (R) associated with the data payload of D = 10011111, given that r=3? b) Add the obtained CRC bits with the payload and check whether the receiver has detected an error or not