Review Questions on Reference Models
1.Which Protocol Data Unit (PDU) is employed at the Transport Layer?
bits
frames
packets
segments
2.Routers operate at which layer of the OSI model?
physical
transport
network
MAC sublayer of the data link layer
session
3. Bits are packaged into frames at which layer of the OSI model?
data link
transport
physical
presentation
application
4. Which of the following are benefits of using a layered network model?
A . it specifies how changes to one layer must be propagated through the other layers
B . it facilitates troubleshooting
C . it focuses on details rather than general functions of networking
D . it breaks the complex process of networking into more manageable chunks
E . it allows layers developed by different vendors to interoperate.
A and B only
B, D, and E
A and C only
none of the above
all of the above
5. Which of the following operate at the presentation layer?
A . MIDI
B . FTP
C . SMTP
D . TFTP
E . JPEG
A and B
A, C, and E
C and E
A and E
none of the above
6. Which of the following are transport layer protocols?
TCP and UDP
IP
FTAM
IP and TFTP
TFTP
7. Which of the following are considered to be the upper layer protocols?
presentation and session
application and presentation
application, presentation, and session
application, presentation, session, and transport
application
8. Flow control takes place at which layer?
physical
transport
network
MAC sublayer of the data link layer
session
9. Encryption takes place at which layer?
application
presentation
session
transport
data link
10.True or False: The network layer uses physical addresses to route data to destination hosts.
True
False
11. Error detection and recovery takes place at which layer?
transport
presentation
data link
application
network
12.Which layer establishes, maintains, and terminates communications between applications located on
different devices?
application
presentation
session
network
data link
13.IP is implemented at which OSI model layer?
transport
session
data link
network
logical link control
14. Which layer handles the formatting of application data so that it will be readable by the destination
system?
application
presentation
session
transport
data link
15. Packets are found at which layer?
data link
transport
network
session
physical
16. What does OSI stand for?
A. International Standards Organization
B. Open Systems Interconnect
C. Operating Standard Information
D. Operating System Interconnection
E. Open Systems Interface
17. Repeaters and hubs operate at which layer?
network
data link
transport
physical
session
18. Bit synchronization is handled at which layer?
data link
session
transport
presentation
physical
19. True or False: most logical addresses are preset in network interface cards at the factory
true
false
20. Bridges operate at which layer of the OSI model?
physical
data link
transport
network
session
21. Which layer is responsible for packet sequencing, acknowledgments, and requests for retransmission?
The MAC sublayer of the data link layer
transport
physical
application
network
22. Match the following:
A. Application Layer
B. Presentation Layer
C. Session Layer
D. Transport Layer
1. Responsible for co-ordinating communication between systems
2. Responsible for multiplexing upper-layer applications
3. Responsible for availability of intended communication partner
4. Responsible for negotiating data transfer syntax
A. A--->3; B--->4; C--->2; D--->1
B. A--->2; B--->4; C--->1; D--->4
C. A--->2; B--->3; C--->4; D--->1
D. A--->3; B--->4; C--->1; D--->2
23. What is the PDU of "Network layer" and "Data link layer".
Discuss
24. What are the differences between OSI and TCP/IP model?
25. How does OSI model help to understand the communication process?