Spring 2020
CPET 281
Local Area Networks and Management
TAP4: Quiz 2 (15%)
| Student Name | Student ID |
| S | Topic | Max Points | Earned Points | Feedback |
| 1 | Question 1 | 10 | ||
| 2 | Question 2 | 10 | ||
| 3 | Question 3 | 10 | ||
| 4 | Question 4 | 10 | ||
| 5 | Question 5 | 10 | ||
| 6 | Question 6 | 10 | ||
| 7 | Question 7 | 10 | ||
| 8 | Question 8 | 10 | ||
| 9 | Question 9 | 20 | ||
| 10 | Bonus | 10 | ||
| Total | 100 |
Q1. (10 points)
Explain using your own words why do we need to place servers geographically close to people who will use these servers?
Q2. (10 points)
Briefly compare how “Flow Control” is different than “Congestion Control” in TCP.
Q3. (10 points)
Calculate the bandwidth of a TCP connection (in bits per second) given that the congestion window size is 20 packets, where each packet is 20 bytes. The round-trip time (RTT) is equal to 20ms. (Hint: a byte is 8 bits).
Q4. (10 points)
TCP can be secured with SSL to encrypt the connection. Does SSL operate at the transport layer (same as TCP) or the application layer? Explain what needs to be done to provide such functionality.
Q5. (10 points)
True or false? Correct the false answers
a. A user requests a Web page that consists of some text and three images. For this page, the client will send one request message and receive four response messages. (T / F)
b. With nonpersistent connections between client browser and web server, it is possible for a single TCP segment to carry two distinct HTTP request messages.
(T / F)
c. The Date: header in the HTTP response message indicates when the object in the response was last modified. (T / F)
d. TCP congestion control ensures that the sender does not overwhelm the receiver with data it cannot handle (T / F)
e. TCP uses a two-way handshake to create a new connection. (T / F)
Q6. (10 points)
Consider a TCP connection between Host A and Host B. Suppose that the TCP segments traveling from Host A to Host B have source port number “x” and destination port number “y”. What are the source and destination port numbers for the segments traveling from Host B to Host A?
Q7. (10 points)
Is it possible for an application to use reliable data transfer when the application runs over UDP? If so, how?
Q8. (10 points)
Suppose a process in Host C has a UDP socket with port number 7889. Suppose both Host A and Host B each sends a UDP segment to Host C with destination port number 7889. Will both segments be directed to the same socket at Host C? If so, how will the process at Host C know that these two segments originated from two different hosts?
Q9. (20 points)
Consider the figure below. What are the source and destination port values in the segments flowing from the server back to the clients’ processes (from the server back to A and B)? What are the IP addresses in the network-layer datagrams carrying the transport-layer segments to each of the hosts?
Bonus (10 points)
a. Do routers have IP addresses? If so, how many?
b. What is the 32-bit binary equivalent of the IP address 131.200.3.26?
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