Tài liệu OSI Reference Model & Layered Communications docx

Topic 1: OSI Reference Model & Layered Communications
1. Choose all terms popularly used as synonyms for MAC address.
A. NIC address.
B. Card address.
C. LAN address.
D. Hardware address.
E. Ethernet address.
F. Token Ring address.
G. FDDI address.
H. Burned-in address.
I. MAC address.
2. What portion of a MAC address encodes an identifier representing the manufacturer of the card (choose two)?
A. The first 3 bytes.
B. The result show interface command for a LAN interface lists the burned in address after the
acronym BIA.
C. The first 6 bytes
D. The first 12 Hexadecimal digits
3. How many bits are present in a MAC address?
A. MAC addresses comprise 48 bits.
B. The first 48 bits for burned-in addresses represent a code that identifies the manufacturer
C. MAC addresses comprise 24 bits
D. MAC addresses comprise 32 bits layer-3 address
4. PDU at the Network layer of the OSI is called what?
A. Core
B. Frames
C. Packets.
D. Segments
E. Access
F. Distribution
G. Transport
5. PDU at the Data Link layer is named what?

A. Frames.
B. Packets
C. Transports
D. Segments
E. Bits
6. Segmentation of a data stream happens at which layer of the OSI model?
A. Physical
B. Data Link
C. Network
D. Transport.
E. Distribution
F. Access
G. Network Protocols
7. Where are routers defined in the OSI model?
A. Physical
B. Transport
C. Data Link
D. Network.
E. Routing
8.
9. At which layer of the OSI are 1s and 0s converted to a digital signal?
A. Physical.
B. Transport
C. Data Link
D. Network
10. Bridges are defined at what layer of the OSI model?
A. Physical
B. Transport
C. Data Link.
D. Network

11. Which one of the following is a characteristic of a switch BUT NOT of a repeater?
A. Device is used to connect 2 Ethernet segments.
B. Device is implemented as a layer in the OSI reference model
C. Device supports simultaneous 10/100 Mbps implementation
D. Device forwards packets based on the destination address in the frame
12. Which one of the following conditions indicates network congestion within a segment?
A. Reasonably fast network response time
B. Significantly slow network response time.
C. File transfers in Internet FTP servers take a long time
D. Delivery of Web Browser request to client takes long time
13. Which one of the following statements is true about the Ethernet switches?
A. Does not forward multicast and broadcast packets to other attached segments
B. Uses multicast and broadcast addresses as source address
C. Filter processing has little or no effect on throughput
D. Broadcast and multicast addresses never appear in the address tables associated with ports.
14. Segmenting LANs with bridges:
A. Occurs at layer 3
B. Reduces the propagation of multicast and broadcast frames
C. Provides fewer users per segment.
D. Uses address tables that associate segment en stations with protocol types
15. An advantage to LAN segmentation is:
A. It places more internetworking devices between clients and servers
B. It provides more bandwidth per user.
C. It reduces WAN costs
D. It increased the number of dumb terminal on the network
16. Error detection in an Ethernet system is performed at which layer of the OSI architectural model?
A. Layer 1
B. Layer 2.
C. Layer 3
D. Layer 4

17. Segmenting LANs with routers
A. Occurs at layer 2
B. Has no effect on the propagation of multicast and broadcast frames
C. Typically costs less per port than bridges or switches
D. Allows multiple paths.
18. Segmenting LANs with switches.
A. Enables multiple high-speed data exchanges.
B. Increases the number of user per segment
C. Occurs sat OSI layer 3
D. Required replacing 802.3 compliant NIC and Cable
19. Which of the following devices can you use to alleviate congestion in an internetwork (Choose all that apply)?
A. Repeaters
B. Routers.
C. DLC
D. Switches.
E. Bridges.



20. How do LAN switches improve performance on a LAN?
A. By filtering via logical address
B. By regenerating the digital signal
C. By employing packet switching that permits high-speed data exchanges
D. By employing frame switching that permits high-speed data exchanges.
21. What is a benefit of bridge segmentation?
A. Regeneration and propagation
B. Segmenting or breaking up your network into smaller, more manageable pieces.
C. LAN queuing
D. Bridges begin forwarding the frame before reception is complete
22. LAN segmentation with switches is also called what?

A. Filtering
B. Micro-segmenting.
C. Bridging
D. Routing
23. How do bridges filter a network?
A. By logical address
B. By IP address
C. By hardware address.
D. By digital signaling
24. How do routers filter a network? (Choose all that apply.)
A. By logical address.
B. By IP address.
C. By digital signaling
D. By hardware address
E. By IPX address.
25. How do switches segment a network?
A. By logical address
B. By IP address
C. By hardware address.
D. By IPX address
26. What is a drawback of filtering a network with bridges?
A. It segments the network
B. It creates internetworks
C. It passes datagram broadcasts.
D. It filters frames
27. How can you reduce route table entries?
A. Route summarization.
B. Incremental updates
C. Filtering
D. VLANs

28. In what order do the five steps of Data Encapsulation take place?
1) User information is converted to data and Data is converted to segments.
2) Segments are converted to packets or datagrams.
3) Packets or datagrams are converted to frames.
4) Frames are converted to bits.
5) Bits are transfer through out media
A. 5,4,3,2,1
B. 1,2,3,4,5
C. 3,2,4,1,5
29. What kinds off services does the Presentation layer provide (Choose all that apply)?
A. PICT, JPEG.
B. MIDI, MPEG.
C. ASCII, EBCDIC.
D. HTTP, FTP
30. What is the Network ID for the IP address 192.168.1.6, assuming default subnet mask?


31. What is the Node ID for the IP address 192.168.1.6, assuming default subnet mask?
32. What is the Network ID for the IPX address 2c.0000.0c55.de09?
33. What is the Node ID for the IPX address 2c.0000.0c55.de09?
34. What kinds off services does the Session layer provide (Choose all that apply)?
A. NFS, SQL.
B. RPC and NetBIOS.
C. MIDI, MPEG
D. ASCII, EBCDIC
35. Which three protocols are correctly matched to transport layer function?
A. TCP.
B. UDP.
C. IP
D. SPX.

36. Which IP-class provides the fewest numbers of Hosts?
A. Class D
B. Class C.
C. Class B
D. Class A
37. Which of the following protocols are used to get an IP address from a known MAC address(Choose all that
apply)?
A. RARP.
B. ARP
C. NetStat
D. BOOTP.
38. A Unique ID placed in the header of each frame as it travels the switch fabric with a UID defined in each frame
is known as:
39. Which OSI layer is responsible for putting 1s and 0s into a logical group?
A. Transport
B. Network
C. Data Link.
D. Physical
40. Which OSI layer is responsible for addressing devices and routing through an internetwork?
A. Transport
B. Network.
C. Data Link
D. Physical
41. Which layer is responsible for flow control, acknowledgment, and windowing?
A. Transport.
B. Network
C. Data Link
D. Physical
42. What is the result of segmenting a network with a router into 2 segments?
A. It prevents one segment’s broadcasts from getting to the other segment.

B. It forward all packets to another broadcast domain
C. It filter MAC addresses
43. Which layer is responsible for coordinating communication between systems?
A. Session.
B. Transport
C. Network
D. Data Link
44. Which layer is responsible for negotiating data transfer syntax?
A. Application
B. Presentation.
C. Session
D. Network
45. Which layer is responsible for synchronizing sending and receiving applications, identifying and establishing the
availability of the intended communication partner, and determining if sufficient resources for the intended
communication exist?
A. Application.
B. Presentation
C. Session
D. Network
46. What is the port number used by TCP?
A. 6.
B. 17
C. 21
D. 25
E. 110
47. What is the port number used by UDP?
A. 6
B. 17.
C. 21
D. 25

E. 110
48. What does the acronym ARP stands for?
49. Which protocol finds a hardware address from a known IP address?
50. Which protocol works at the Internet layer of the DOD model and it’s responsible for making routing decisions?
A. IP.
B. ICMP
C. TCP
D. UDP
51. Which port numbers are used by TCP and UDP to set up sessions with other hosts?
>= 1023

52. The UDP works at which layer of the DOD model?
Host-to-host (transport)

53. Which protocol sends redirects back to an originating router?
A. Internet Control Message Protocol – ICMP.
B. User Datagram Protocol – UDP
C. File Transfer Protocol – FTP
D. Transport Control Protocol – TCP
54. Ping uses which Internet layer protocol?
A. ICMP.
B. TCP
C. UDP
D. FTP
55. Which protocols use the Transport layer (Choose all that Apply)?
A. TCP.
B. UDP.
C. IPX
D. IP
E. SPX.

56. Which of the following is a connectionless protocol that uses the Transport layer?
A. TCP
B. UDP.
C. IPX
D. IP
E. SPX
57. You have 8 stations connected to separate 10 Mbps ports on a layer 2 switch. How many Mbps of bandwidth
will each port have?
A. <10
B. 10.
C. 20
D. 80
58. What does the User Datagram Protocol (UDP) provide?
A. Connectionless.
B. Connection-Oriented
59. What two OSI layers controls end-to-end communication?
A. Application.
B. Presentation
C. Session
D. Transport.
E. Network
60. What LAN segmentation rule is specified by Cisco?
A. 70% local, 30% over the router.
B. 80% Local, 20% over the router
C. 20% Local, 80% over the router
61. What is true about connection-oriented sessions (Choose all that apply)?
A. Sessions take place at Transport Layer
B. TCP is responsible for segment delivery
C. Unacknowledged segments are resent
D. The sender acknowledges all received data

E. Segments are sequenced and put back into order upon arrival
F. All of above.
62. What 3 functions are supported by connection-oriented services (Choose all that apply)?
A. Connection parameters are synchronized.
B. Loss or duplication of packets can be corrected.
C. Segments are sequenced and put back into order upon arrival
D. A data communication path is established between requesting and receiving device.
63. What's the default subnet mask for a Class A IP address?
64. What's the default subnet mask for a Class B IP address?
65. What's the default subnet mask for a Class C IP address?

Topic 2: Bridging and Switching
66. The major benefit of VLAN is that it allows creation of workgroups based on?
A. Functions.
B. Physical location
C. Switching technology
D. Transmission media
67. For Catalyst switches, which of the following commands is used to obtain a summary of advertisements
transmitted?
A. Show VTP Domain
B. Show VTP statistics.
C. Show port status
D. Show router status
68. What is a reason to create a VLAN?
A. Mingle non-routable protocol traffic with routable traffic
B. Create a non-secure network
C. Disperse videoconferencing traffic with other traffic
D. Isolate non-routable protocol traffic.
69. Select the three functions of a layer 2 switch:
A. Learn the MAC addresses of hosts connected to ports.

B. Store MAC addresses mapped to ports in a switching table.
C. Route data based on network layer address
D. Forward data based on the MAC address.
70. When might a Bridge Protocol Data Unit have to be used?
A. In a changing network topology.
B. In a static network topology
C. To indicate which ports are to be opened for traffic
D. All of the above
71. Switching is a term most commonly used to describe:
A. Layer 1 devices
B. Layer 2 devices.
C. Layer 3 devices
72. Identify two common trunking protocols.
A. PNNI and OSPF
B. IEEE 802.3 and IEEE 802.5
C. IEEE 802.1D and LAN Emulation
D. ISL and IEEE 802.1Q.
73. When is frame tagging used?
A. When VLANs are traversing an access link
B. When VLANs are traversing a trunked link.
C. When ISL is used on an access link
D. When 802.1Q is used on an access link
74. Which LAN switch method runs a CRC on every frame?
A. Cut-through
B. Store and forward.
C. FragmentCheck
D. FragmentFree
75. Which LAN switch type only checks the hardware address before forwarding a frame?
A. Cut-through.
B. Store and forward

C. FragmentCheck
D. FragmentFree
76. What is true regarding the STP blocked state of a port? (Choose all that apply.)
A. No frames are transmitted or received on the blocked port.
B. BPDUs are sent and received on the blocked port
C. BPDUs are still received on the blocked port.
D. Frames are sent or received on the block port


77. How does "Store-and-Forward" LAN switching method work?
A. Switch waits for the whole frame before forwarding.
B. Latency varies with different frame sizes.
C. Switch will forwarding the whole frame as soon as it read DA
D. Switch will only forwarding the first 13 Bit inside frame
78. If a frame is received at a switch and only the destination hardware address is read before the frame is
forwarded, what type of switching method are you using?
A. Cut-through.
B. Store and forward
C. FragmentFree
D. All of above
79. Which two of the following describe frame tagging?
A. Examines particular info about each frame
B. A unique ID placed in the header of each frame as it traverses the switch fabric.
C. A user-assigned ID defined to each frame.
D. The building of filter tables
80. Which type of switching is considered to be 'wire speed?'
A. Layer 3
B. Cut-through.
C. Store and forward
D. Layer 4

81. What is a characteristic of Store and Forward switches?
A. They increase latency.
B. They forward based on transport layer info
C. They are the same as Cut-Through switching in 'prune' mode
D. They forward the frame before it is completely read
E. They work at wire speed
82. What type of switching creates variable latency through the switch?
A. Store and Forward.
B. Layer 4
C. Layer 3
D. Cut-through.
83. What does the Spanning-Tree Algorithm (STA) do?
A. Implemented by STP to prevent loops by creating a spanning tree.
B. Implemented VLAN trunking Protocol
C. Provide redundancy connectivity to another logical network
84. Of the different switching types, which one has the lowest latency?
A. Cut-Through.
B. Store-and-Forward
C. FragmentFree
85. Of the different switching types, which one has the highest latency?
A. Store-and-Forward.
B. Cut-Through
C. FragmentFree
86. Which is true regarding store-and-forward switching method?
Latency depends on frame length

87. What two technologies prevent network loops in a switched environment?
A. Spanning Tree Protocol and IEEE 802.ld.
B. IEEE 802.3 and IEEE 802.5
C. IEEE 802.1D and LAN Emulation

D. ISL and IEEE 802.1Q
88. Which statement from a “show spantree 1” command output shows that the Virtual LAN 1 is functioning?
A. VLAN1 is executing the IEEE compatible Spanning-Tree Protocol.
B. VLAN1 is executing VLAN trunking protocol
89. Which of two the following are true of Per VLAN Spanning Tree?
A. ISL supports Per VLAN Spanning Tree.
B. Per VLAN Spanning Tree only works on Cisco5xxx with software 4.1 or better
C. A significant advantage of Per VLAN Spanning Tree in a large campus network is that the choice of
the root bridge can be optimized for each VLAN.
D. ISL trunking requires Common Spanning Tree
90. What is a virtual LAN?
A. A routed internet
B. A shared physical media
C. A group of ports in the same broadcast domain.
D. A shared collision domain
91. Compared to bridging, layer 2 switching has which of the following characteristics?
A. Less flexibility
B. Lower latency
C. Performs the same function but bridging and switching are implemented differently
D. Switching is software based and bridges are implemented in hardware.
92. What switching technology reduces the size of a broadcast domain?
A. VLAN.
B. Spanning tree
C. Trunking
D. Dependent on IOS of Cisco Switch
Topic 3: Network Protocols
93. What is the Network ID for the IP address 192.168.12.6, assuming default subnet mask?
A. 192.168.12.0.
B. 0.0.12.0
C. 192.168.0.0

94. What is the Node ID for the IP address 192.168.12.6, assuming default subnet mask?
A. 0.0.0.6.
B. 192.168.12.0
C. 192.168.0.0
95. What is the Network ID for the IPX address 2c.0000.0c56.de34?
A. 2c.
B. 2c.0000
C. 0c56.de34
D. de34
96. What is the Node ID for the IPX address 2c.0000.0c56.de34?
A. 0000.0c56.de34.
B. 2c.0000
C. 0c56.de34
97. What's the default subnet mask for a Class A IP address?
A. 255.0.0.0.
B. 255.255.0.0
C. 255.255.255.0
98. What's the default subnet mask for a Class B IP address?
A. 255.255.0.0.
B. 255.0.0.0
C. 255.255.255.0
99. Given the following IP address: 162.53.21.12. You plan for no more than 126 hosts on the subnet that includes
this address. What subnet mask would you use?
A. 255.255.255.128.
B. 255.255.255.242
C. 255.255.255.192
100. You have a class B IP address with a 12 bits subnet. How many subnets and hosts are available?
A. 4094 subnets, 14 hosts.
B. 1024 subnets, 30 hosts
101. You have an IP address of 153.50.6.27 and a subnet mask of 255.255.255.128. What is the class, how

many bits are being subnetted, and what is the broadcast address?
A. Class B, 9 bits, 153.50.6.127.
B. Class B, 8 bits, 153.50.6.192
C. Class B, 10 bits, 153.50.6.64
102. Which IP host address range is allowable given an IP address of 169.73.3.55 using 12 bits of sub-netting?
A. 169.73.3.49 through 169.73.3.62.
B. 169.73.3.48 through 169.73.3.63
103. Given an IP host address of 169.61.3.151 and a subnet mask of 255.255.255.192, which subnet does this
host belong to?
A. 169.61.3.128.
B. 169.61.3.64
C. 169.61.3.127
104. To specify all hosts in the class B IP network 172.16.0.0, which wildcard access list mask would you use?
A. 0.0.255.255.
B. 0.0.0.255
C. 0.255.255.255
105. How many valid host IP addresses are available on the following subnetwork? 167.21.41.17/30
A. 2.
B. 4
C. 6
106. You need two subnets with 35 users each. Which subnet mask would you use on your class C network
address to accomplish this?
A. 255.255.255.192.
B. 255.255.255.128
C. 255.255.255.242
107. If you wanted to subnet your class C networks into 2 subnets, what would you use as a subnet mask?
A. 255.255.255.128
B. 255.255.255.192.
C. 255.255.255.224
108. What can you say about the following network address? 255.255.255.255

A. It is an IP address identifying a flooded broadcast.
B. It is an IP address identifying a flooded multicast
C. It is an IP address identifying a network address
109. What type of address protocol is being used and what is the second part of this network address?
172.16.0.254 mask = 255.255.0.0 (choose 2)
A. Private IP address.
B. Node number.
C. Network Address
110. Given the IP address 220.8.7.100 and the mask 255.255.255.240, what are last the subnet numbers if the
same (static) mask is used for all subnets in this network?
A. 220.8.7.0
B. 220.8.7.16
C. 220.8.7.32
D. 220.8.7.48
E. 220.8.7.64
F. 220.8.7.80.
111. What causes the output from an IOS ping command to display “UUUUU?”
A. Unreachable.
B. ICMP Echo Reply received
C. Unknown packet received
112. How many bytes comprise an IPX address and how many bytes NetID part/HostID part?
113. Given the IP address 220.8.7.100 and the mask 255.255.255.240, what is the broadcast address?
114. Given the IP address 140.1.1.1 and the mask 255.255.255.248, what is the broadcast address?
115. How many IP addresses could be assigned in each subnet of 10.0.0.0, assuming that a mask of
255.255.255.0 is used? If the same (static) mask is used for all subnets, how many subnets are there?
116. How many IP addresses could be assigned in each subnet of 220.8.7.0, assuming that a mask of
255.255.255.240 is used? If the same (static) mask is used for all subnets, how many subnets are there?
117. How many IP addresses could be assigned in each subnet of 140.1.0.0, assuming a mask of
255.255.255.248 is used? If the same (static) mask is used for all subnets, how many subnets are there?
118. Which protocol working at the Transport layer provides a connection-less service between hosts?

A. IP
B. TCP
C. UDP.
119. Which protocol works at the Transport layer and provides virtual circuits between hosts?
A. IP
B. ARP
C. TCP.
D. UDP
120. Which protocol works at the Internet layer and provides a connectionless service between hosts?
A. IP.
B. ARP
C. TCP
D. UDP
121. What do IPX and SPX stand for?
122. How many Class B-style networks are reserved by RFC1918 private addressing?
123. Given the IP address 134.141.7.11 and the mask 255.255.255.0, what is the subnet number?
124. Given the IP address 134.141.7.11 and the mask 255.255.255.0, what is the subnet broadcast address?
125. If a host broadcasts a frame that includes a source and destination hardware address, and its purpose is to
assign IP addresses to itself, which protocol at the Network layer does the host use?
A. RARP
B. ARPA
C. ICMP
D. TCP
E. IPX
126. What is the valid host range the IP address 172.16.10.22 255.255.255.240 is a part of?
A. 172.16.10.20 through 172.16.10.22
B. 172.16.10.1 through 172.16.10.255
C. 172.16.10.16 through 172.16.10.23
D. 172.16.10.17 through 172.16.10.31
E. 172.16.10.17 through 172.16.10.30.

127. What range of addresses can be used in the first octet of a Class B network address?
A. 1–126
B. 1–127
C. 128–190
D. 128–191.
E. 129–192
F. 192–220
128. What is the broadcast address of the subnet address 10.254.255.19 255.255.255.248?
A. 10.254.255.23.
B. 10.254.255.24
C. 10.254.255.255
D. 10.255.255.255
129. What is the broadcast address of the subnet address 172.16.99.99 255.255.192.0?
A. 172.16.99.255
B. 172.16.127.255.
C. 172.16.255.255
D. 172.16.64.127
130. If you wanted to have 12 subnets with a Class C network ID, which subnet mask would you use?
A. 255.255.255.252
B. 255.255.255.248
C. 255.255.255.240.
D. 255.255.255.255
131. What is the broadcast address of the host subnet address 10.10.10.10 255.255.254.0?
A. 10.10.10.255
B. 10.10.11.255.
C. 10.10.255.255
D. 10.255.255.255
132. Which protocol does DHCP use at the Transport layer?
A. IP
B. TCP

C. UDP.
D. ARP
133. Which protocol does Ping use?
A. TCP
B. ARP
C. ICMP.
D. BootP
134. Which protocol is used to find an Ethernet address from a known IP address?
A. IP
B. ARP.
C. RARP
D. BootP
E.
F.
135. Which protocol is used to send a Destination Network Unknown message back to originating hosts?
A. TCP
B. ARP
C. ICMP.
D. BootP
136. Which of the following is the valid host range for the IP address 192.168.168.188 255.255.255.192?
A. 192.168.168.129–190.
B. 192.168.168.129–191
C. 192.168.168.128–190
D. 192.168.168.128–192