CSCI 547 Computer Networks Final Exam
SPRING 2006
Closed book, closed
notes. Some questions have
multiple answers!
There are more than
100 points. Answer all questions!
Name:___________________________________
1.(6 points) IEEE 802 protocols
Match the following
802 protocols with a description. Draw lines between them.
|
802.1 802.2 802.3 802.11 802.3u 802.3z |
|
Wireless Access Protocol
& Physical layer 100M bps Ethernet 1000M bps Ethernet Higher layer interface to
802 protocols Logical Link Control CSMA/CD & Physical
layer |
2.(5 points) Connection-oriented service’s
responsibilities are:
Choose all that
apply.
|
|
a. |
Initialization of the connection |
|
|
b. |
Error detection using CRC code |
|
|
c. |
Resetting the link in case of an error |
|
|
d. |
Flow control |
|
|
e. |
Termination of the connection |
|
|
f. |
Sending a “keep alive” messages to keep the link intact |
|
|
g. |
Retransmit a message in case of timeout |
3.(1 points) Dotted decimal notation
Given the following
IP address in binary, what is its dotted decimal equivalent?
10000100 11110001
10011110 00100011
|
|
a. |
132.243.148.32 |
|
|
b. |
123.142.150.33 |
|
|
c. |
132.241.158.34 |
|
|
d. |
132.241.156.35 |
4.(6 points) Subnet masks
For the subnetting scheme which allows all 0’s and all 1’s subnetids(such as CIDR), choose all the possible subnet
masks.
|
|
a. |
64 |
|
|
b. |
128 |
|
|
c. |
192 |
|
|
c. |
220 |
|
|
d. |
224 |
|
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e. |
240 |
|
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f. |
242 |
|
|
g. |
248 |
|
|
h. |
250 |
|
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i. |
252 |
|
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j. |
254 |
|
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k. |
255 |
5.(1 points) Identify IP address
Identify the following
IP address: 132.241.0.0
|
|
a. |
host IP address |
|
|
b. |
direct broadcast address |
|
|
c. |
limited broadcast address |
|
|
d. |
network address |
6.(1 points) Identify IP address
Identify the following
IP address: 132.241.255.255
|
|
a. |
host IP address |
|
|
b. |
direct broadcast address |
|
|
c. |
limited broadcast address |
|
|
d. |
network address |
7.(4 points) Getting IP address
A host can get its
IP address from its DHCP server by using _____ as the source address and ____
as the destination address.
|
|
a. |
255.255.255.255 ; 127.0.0.1 |
|
|
b. |
127.127.127.127 ; 0.0.0.0 |
|
|
c. |
0.0.0.0 ; 255.255.255.255 |
|
|
d. |
255.255.255.255 ; 0.0.0.0 |
|
|
e. |
none of the above |
8.(3 points) TCP/IP configuration
Among many
configuration parameters, which three(3) are the most essential settings for
TCP/IP networking?
|
|
a. |
IP address |
|
|
b. |
WINS server |
|
|
c. |
Subnet mask |
|
|
d. |
Default Gateway |
|
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e. |
DNS server address |
|
|
f. |
Computer’s name |
9.(3 points) Through a
router?
A host with IP
address 132.241.158.70 with subnet mask of 255.255.255.240 sends a message
to a host with IP address 132.241.158.60. Does the message travel through any
router?
|
|
a. |
Yes |
|
|
b. |
No |
10.(3 points) Through a
router?
A host with IP
address 132.241.158.35 and subnet mask 255.255.255.224 sends a message to a host
with IP address 132.241.158.52. Does the message travel through any router?
|
|
a. |
Yes |
|
|
b. |
No |
11.(4 points) Supernet mask
Which one should be
the "supernet mask" to combine 16 class C network addresses?
|
|
a. |
255.255.255.192 |
|
|
b. |
255.255.252.0 |
|
|
c. |
255.255.248.0 |
|
|
d. |
255.255.240.0 |
|
|
e. |
255.255.224.0 |
|
|
e. |
255.255.192.0 |
12.(2 points)Default mask
Which of the
following is the default subnet mask(before any subnetting is done) for the address
132.241.158.240?
|
|
a. |
255.0.0.0 |
|
|
b. |
255.255.0.0 |
|
|
c. |
255.255.255.0 |
|
|
d. |
255.255.255.224 |
13.(3 points) How many hosts
per subnet?
A subnet mask of
255.255.255.252 allows how many hostids per subnet?
|
|
a. |
30 |
|
|
b. |
14 |
|
|
c. |
6 |
|
|
d. |
2 |
14.(1 points) Fragmentations
When a router
cannot deliver an IP datagram in its original size, the router fragments IP
datagram into several fragments. Who is responsible for reassembling the
fragments?
|
|
a. |
Router at the destination network |
|
|
b. |
All intervening routers where fragments occur |
|
|
c. |
Destination host |
15.(3 points) IPv6
What are the main
improvements in IPv6 over IPv4? Choose all that apply.
|
|
a. |
Larger address space |
|
|
b. |
Smaller header size |
|
|
c. |
More elaborate error checking on the header portion |
|
|
d. |
Provides better Quality of Service features |
|
|
e. |
With IPv6, we do not need MAC addresses anymore |
16.(3 points)
When you issue
“ping 127.0.0.1” in Command Prompt window, you are checking what?
17.(4 points) Well-known & Ephemeral
Point out the
difference(s) between “well-known port numbers” and “ephemeral port numbers”.
18.(2 points) Winsock
What is “Winsock”?
19.(4 points) TCP Active/Passive Open
What is the
difference between TCP’s “Active open” and “Passive open”?
20.(4 points) Persistent vs Non-persistent http
Point out the
difference(s) between “Persistent http” and “Npn-Persistent http”.
21.(4 points) Supernetting(also called as
CIDR(Classless InterDomain Routing))
Why do we need
supernetting?
22.(4 points) Variable Length Subnet Mask(VLSM)
What is the main
idea of VLSM?
23.(4 points) RIP vs OSPF
What are the main advantages
of OSPF over RIP?
24.(10 POINTS) Block diagram for IP module is given
below. Describe how each component operates for the following scenarios.
(a) Let’s say, it is a router and the router received a packet. What would the
IP module of the router do? Include the names of the participating components
in your description.
(b) A host received a packet addressed to it’s IP address. What would the IP
module of the host do? Include the names of the participating components in
your description
25.(10 POINTS) Mail access protocols
There are three Mail access protocols(for the retrieval
of e-mails from mail server). Point out
the differences between them.
v POP: Post Office Protocol
v IMAP: Internet Mail Access Protocol
v HTTP(web based):
26.(9 points) Solutions to IP address space?
IP address space
for IPv4 is running out. What are the three
main solutions to the problem? Briefly describe each of them.
27.(10 points) Fill in
the diagram of TCP/IP protocol stack. List all protocols on each layer(also show the protocols that are at the boundary
of layers):
|
OSI Layer number |
TCP/IP Protocols |
|
Layer 7 |
|
|
Layer 6 |
|
|
Layer 5 |
|
|
Layer 4 |
|
|
Layer 3 |
|
|
Layer 2 |
Not defined in
TCP/IP |
|
Layer 1 |
Not defined in
TCP/IP |
28.(4 points) One of
the reasons that Ethernet dominates the LAN protocols is”backward
compatibility”. Describe how the “backward compatibility” is achieved. Include
the word “autonegotiation”.
29.(4 points) Describe how web proxy servers work.