Bandwidth Requirement

I would advise that you become familiar with the bandwidth calculators here:

http://www.troylister.com/html/bandwidth_calculators_.htm

The folks at OPNet make a LOT of money doing this for companies:

http://www.opnet.com/products/modules/flow_analysis.html

I'd recommend that you read IT Systems Management: Designing, Implementing, and Managing World-Class Infrastructures by Rich Schiesser. It should be available in any technical college library.

I also recommend A Spare Capacity Planning Methodology for Wide Area Survivable Networks
by Adel A. Al-Rumaih. This may be available in your library, if not, it is available here:

http://dissertation.com/book.php?method=ISBN&book=158112046X

Another interesting take on the subject is covered here:

http://itmanagement.earthweb.com/erp/article.php/3400851

To be honest, capacity planning is a holistic art which involves an understanding of each element and how the entire system interacts. An example being:

The amount of mail sent and recieved will affect both local network traffic to clients and servers, WAN, as well as, the Internet link. And how the system utilizes the TCP/IP packet for sending information will also increase or decrease bandwidth utilization.

So your first step is to find out what OSes are running on workstations, laptops and servers. Then determine the WAN and local area segment speeds and utilizations. Then see what the connectivity is to the outside world (known as the Committed Information Rate [CIR] on a data line) and it's utilization. How much mail? How many attachments? What size are the attachments?

Best of luck.

just one small point to remember.

bandwidth means range of frequencies used.
high speed is full bandwidth, measured in MegaHerz
( fiber optics are from low end radio frequencies through to high end light [ ultra violet ] frequencies )

what you are actually being asked for is required DATA TRANSFER CAPACITY, measured in gigabits ( not gigabytes )

give the course instructor crap for not using correct nomeclature. accuracy in terminology helps avoid confusion.

You don?t need much, the school I went to and do work for uses fiber to connect the high school to the JR High and from the JH to the 2 other elementary schools. Really bandwidth is not that big of an issue when your connecting things like schools because usually schools would never have much load between 2 schools. But I would say 200 computers for a fast fiber line is not bad at all considering we have over 4000 computers in the school district. We use a dedicated OS X server with synchronies LDAP server and file server for whole district login.