a) Error checking is performed at both data link and transport layers. Explain why error checking is necessary in both layers? [4 marks] b) You have started working as a network administrator in Star Global Solutions. The company has two buildings located approximately 1.5 Km apart. The company wants to interconnect the two buildings so that the data can be transferred at a speed of 100Mbps or over. The company has a limited budget for this setup. Propose a possible solution which is technically feasible as well as financially affordable. [4 Marks] QUESTION 2: [4+4 = 8 Marks] a) Discuss the medium required to support wavelength division multiplexing? Differentiate between dense wavelength multiplexing and coarse wavelength division multiplexing. [4 Marks] b) Discuss time division multiplexing (TDM). What are the main differences between statistical time division multiplexing and synchronous time division multiplexing? [4 Marks] a) Discuss two basic forms of compression. Given the following data string, present the result using run-length encoding. By what percentage is the data compressed? 0000011000000001000000000100001100000000