CS 320 – Data Communications: Assignment #1

(Professor Arnold Toffler Office: 4250, (973) 618-3459, Atoffler@caldwell.edu)

Answer the following questions:

1. List the OSI layer that performs each of the following functions:

a. data compression

b. multiplexing

c. routing

d. definition of a signal’s electrical characteristics

e. error detection

f. end-to-end flow control

2. For each of the functions described in the previous exercise, list the Internet layer (TCP/IP) that performs that function.

3. You want to download a file from a remote site using the File Transfer Protocol (FTP). To perform the file transfer, your computer issues a Get File command. Show the progression of messages as the Get File command moves from your computer, through your LAN, out across the internet through a router and into a recipient router at your destination, into the remote LAN and finally to the destination computer, and back. Show the changes in the application packet as it progresses. You may use a diagram or your own well thought out words to explain the flow. (Refer to Figure 1-19 (p.26) in your textbook.)

4. Explain how a Denial of Service Attack (DoS) occurs. (Refer to presentation on TCP/IP Problems.)

Assignment is due 2/14/2008.