Software Engineering Foundations: Operating Systems and Networks Unit 11: Network Layers 
 
Submit your answers for problem 1 and 2 to quiz Homework Unit 11 and for problem 3 to the corresponding dropbox. 
Problem 1 – 2 Points 
XYZ Corp.'s Nashua, NH, facilities are two office buildings 400 feet apart, each with its own LAN. To connect the two networks, you plan to dig a trench and lay cable between the two buildings. You want to use fiber-optic cable, but your budget-conscious facilities manager wants to use 100 Mbps Ethernet over twisted-pair. What reasons can you use to justify fiber-optic cable in this case? (mark all that are correct).  

A) Twisted-pair is a conductive cable and can, therefore, carry current if lightning strikes in the vicinity, possibly damaging the network.  

B) Fiber-optic leaves more room for growth and future needs for increased bandwidth than twisted-pair does. 

C) Fiber-optic cable is cheaper and easier to work with than twisted-pair. 

D) Twisted-pair will not span a 400-foot distance. 

Problem 2 – 2 Points 
What layer of the OSI reference model is responsible for the following problem?  
A machine in the computer lab has lost network connection. It appears that the network adapter is causing the problem.  

A) transport layer   

B) network layer   

C) data link layer   

D) session layer   

Problem 2 – 6 Points 
Web Start Inc is hiring you to help them reconfigure their computer network. The company currently occupies a single floor in a building with 20 offices, each containing a single workstation. Employees share a single network printer and a single file server to store company files. The company uses a single hub to connect the office machines, server, and printer as well as a single router to connect the company’s intranet to the Internet.  
 
The company now wants to expand their business to the second floor of the building that provides 30 more office spaces. Each office is to be equipped with another workstation. A second file server and two more network printers will be added that may be shared by all employees.  Each room on the second floor provides a wall jack for connecting to the network. A network room on the second floor provides a single patch panel for connecting individual offices. Also, assume that a network cable (cat 5) connects the patch panel of the first floor with the patch panel on the second floor. No other networking equipment is available on the second floor. 

A) Draw up a low cost/low performance and a high cost/high performance plan of a network design that solves the company’s new requirements. 

B) Come up with a cost proposal for each plan using resources on the Internet to determine the individual network equipment costs. Don’t consider including the cost of work stations, printers, servers and software into the proposal. Only focus on the cost of networking hardware.