TRUE/FALSE
1. The maximum extent of a local area network is one building.
ANS: F
2. An organization could have several local area networks in the same room.
ANS: T
3. LANs can allow several people to access the same file at the same time.
ANS: T
4. LANs often use "dumb" terminals as workstations.
ANS: F
5. On a circuit-switched network, a data stream has a channel all to itself for the duration of the connection.
ANS: T
6. A "node" is a workstation or PC connected to a network.
ANS: T
7. In a star network, if one node fails, the entire network goes down.
ANS: F
8. Hubs are, by definition, passive.
ANS: F
9. Token passing can be implemented as a ring or as a bus.
ANS: T
10. A token is used to control access to the network.
ANS: T
11. A token is generated by a node wishing to access the network.
ANS: F
12. On a bus network, all traffic shares a common channel.
ANS: T
13. CSMA networks must deal with "contention".
ANS: T
14. Token-passing networks must deal with "collisions" between two tokens.
ANS: F
15. On a CSMA/CD network, several nodes can try to access the channel simultaneously.
ANS: T
16. A "collision" will take a CSMA network down.
ANS: F
17. Token rings never have collisions.
ANS: T
18. CSMA works best when traffic is relatively light.
ANS: T
19. A token-ring network can be implemented with a bus topology.
ANS: T
20. A MAU will disconnect a defective node from a CSMA network.
ANS: F
21. Token-ring networks usually operate at 100 megabits per second.
ANS: F
22. Most LANs are based on the Ethernet type of network.
ANS: T
23. Ethernet was originated by Microsoft with participation by Intel.
ANS: F
24. IEEE 802.3 is a protocol based on Ethernet.
ANS: T
25. Ethernet-type networks are limited to a maximum speed of 100 Mbits per second.
ANS: F
26. Classic Ethernet is no longer used for new networks.
ANS: T
27. Originally, Ethernet used 10Base2 coaxial cable.
ANS: F
28. 100BaseT cable could be used in a new LAN installation.
ANS: T
29. The "100" in 100BaseT designates the supported bit rate.
ANS: T
30. The "Base" in 100BaseT indicates the cable carries an unmodulated signal.
ANS: T
31. The "T" in 100BaseT indicates the cable is Thick coax.
ANS: F
32. Ethernet uses CSMA/CD.
ANS: T
33. Ethernet type LANs use token passing.
ANS: F
34. In CSMA, a node must "listen" to the channel before trying to use it.
ANS: T
35. 10BaseT cable usually uses RJ-45 connectors.
ANS: T
36. 100BaseT cable requires a BNC connector.
ANS: F
37. Ethernet cannot use fiber-optic cables.
ANS: F
38. Packets on a CSMA/CD network must be equal to or longer than some minimum size.
ANS: T
39. On a CSMA/CD network, there will be fewer collisions if longer packets are used.
ANS: T
40. Longer packets means more bits must be retransmitted after a collision.
ANS: T
41. On a CSMA/CD network, only one node actually needs to "hear" a collision.
ANS: F
42. A NIC gives a unique address to a node on a network.
ANS: T
43. If coax is used, the ends must be left open to avoid reflections.
ANS: F
44. Typically, a NIC requires a 4-wire cable to connect to a hub.
ANS: T
45. CAT-5 UTP is actually the same as ordinary twisted-pair telephone wire.
ANS: F
46. Standard Manchester line encoding can be used up to 100 Mbits per second.
ANS: F
47. If 10BaseT cabling is used in a multinode LAN, then a hub cannot be used.
ANS: F
48. Compared to a hub, a switch reduces the chances for a collision.
ANS: T
49. "Jabber" is failure mode for a NIC.
ANS: T
50. "Stacking" is a failure mode for a hub.
ANS: F
51. Network software is generally independent of the network topology.
ANS: T
52. The same network software can be used on a token-passing network and on an Ethernet LAN.
ANS: T
53. To a user on the network, a hard drive on the server looks like it is on the workstation.
ANS: T
54. In a client-server network, each node takes a turn at being the server.
ANS: F
55. Software that runs a client-server network must have true multitasking ability.
ANS: T
MULTIPLE CHOICE
1. CSMA stands for:
a. | Client-Server Multi-Access | c. | Carrier Server Master Application |
b. | Carrier Sense Multiple Access | d. | none of the above |
ANS: B
2. The CD in CSMA/CD stands for:
a. | Carrier Detection | c. | Collision Detection |
b. | Carrier Delay | d. | Collision Delay |
ANS: C
3. The Internet is:
a. | a network of networks | c. | a very large CSMA/CD network |
b. | a very large client-server network | d. | not really a network at all |
ANS: A
4. Most LANs:
a. | are based on Ethernet | c. | use UTP cable |
b. | use CSMA/CD | d. | all of the above |
ANS: D
5. Dumb terminals are still used:
a. | in token-passing networks |
b. | in networks requiring central monitoring |
c. | in networks that cannot provide central monitoring |
d. | none of the above |
ANS: B
6. In a circuit-switched network:
a. | communication is half-duplex only |
b. | each channel carries only one data stream |
c. | connection is usually done using a bus topology |
d. | all of the above |
ANS: B
7. Each computer on a network is called a:
a. | hub | c. | node |
b. | token | d. | circuit |
ANS: C
8. Compared to CSMA/CD systems, token-passing rings are:
a. | slower | c. | not as widely used |
b. | more expensive | d. | all of the above |
ANS: D
9. The key feature of a star network is that individual workstations are connected to:
a. | a central ring | c. | a node |
b. | a central bus | d. | none of the above |
ANS: D
10. On networks, long messages are divided into "chunks" called:
a. | packets | c. | carriers |
b. | nodes | d. | tokens |
ANS: A
11. When two or more PCs try to access a baseband network cable at the same time, it is called:
a. | a collision | c. | excess traffic |
b. | contention | d. | multiple access |
ANS: B
12. When two PCs send data over a baseband network cable at the same time, it is called:
a. | a collision | c. | excess traffic |
b. | contention | d. | multiple access |
ANS: A
13. One type of network that never has a collision is:
a. | CSMA | c. | token-passing |
b. | Ethernet | d. | all networks have collisions |
ANS: C
14. In an Ethernet-based network, a switch can be used to reduce the number of:
a. | nodes | c. | packets |
b. | users | d. | collisions |
ANS: D
15. The effect of too many collisions is:
a. | the network goes down | c. | the cable overheats |
b. | the network slows down | d. | data is lost |
ANS: B
16. MAU stands for:
a. | Multistation Access Unit | c. | Multiple Auxiliary Units |
b. | Multiple Access Unit | d. | none of the above |
ANS: A
17. The standard that describes Ethernet-type networks is:
a. | EIA 232 | c. | IEEE 802.3 |
b. | IEEE 488.1 | d. | CCITT ITU-E |
ANS: C
18. Ethernet was invented by:
a. | IBM | c. | Xerox |
b. | INTEL | d. | Digital Equipment Corporation |
ANS: C
19. An Ethernet running at 10 Mbits / second uses:
a. | Manchester encoding | c. | NRZ encoding |
b. | Three-Level encoding | d. | AMI encoding |
ANS: A
20. A 100BaseT cable uses:
a. | fiber-optic cable | c. | RG-58U coaxial cable |
b. | twisted-pair copper wires | d. | 50-ohm coaxial cable |
ANS: B
21. The word "Base" in 10BaseT means:
a. | the cable carries baseband signals |
b. | the cable has a base speed of 10 Mbps |
c. | it can be used as the base for a backbone cable system |
d. | none of the above |
ANS: A
22. The reason a CSMA/CD network has a minimum length for packets is:
a. | to increase the data rate |
b. | to prevent packets from reaching all other nodes during transmission |
c. | to make sure all other nodes hear a collision in progress |
d. | all of the above |
ANS: C
23. The reason a CSMA/CD network has a maximum length for cables is:
a. | to increase the data rate |
b. | to prevent packets from reaching all other nodes during transmission |
c. | to make sure all other nodes hear a collision in progress |
d. | all of the above |
ANS: C
24. NIC stands for:
a. | Network Interface Card | c. | Network Interface Code |
b. | Network Interface Cable | d. | Network Internal Code |
ANS: A
25. 10BaseT cable typically uses:
a. | a BNC connector | c. | an RJ45 connector |
b. | a T connector | d. | an RS11 connector |
ANS: C
26. UTP stands for:
a. | Untwisted-Pair copper wire | c. | Uninterruptible Terminal Packet |
b. | Unshielded Twisted-Pair copper wire | d. | Unicode Text Packet |
ANS: B
27. Compared to twisted-pair telephone cables, CAT-5 cables:
a. | are cheaper | c. | allow faster bit rates |
b. | are easier to crimp connectors onto | d. | all of the above |
ANS: C
28. A hub:
a. | sends incoming packets out to all other terminals connected to it |
b. | sends incoming packets out to specific ports |
c. | cannot be used in an Ethernet-type network |
d. | are more common in token-passing networks |
ANS: A
29. A switch:
a. | sends incoming packets out to all other terminals connected to it |
b. | sends incoming packets out to specific ports |
c. | cannot be used in an Ethernet-type network |
d. | are more common in token-passing networks |
ANS: B
30. An advantage of using a switch instead of a hub is:
a. | it is cheaper when used in large networks |
b. | it is faster when used in large networks |
c. | it reduces the number of collisions in large networks |
d. | all of the above |
ANS: C
31. Broadband LANs:
a. | modulate the data onto a carrier |
b. | use coaxial cables |
c. | are provided by cable TV companies for Internet access |
d. | all of the above |
ANS: D
32. Using one node in the network to hold all the application software is done in:
a. | peer-to-peer networks | c. | both a and b |
b. | client-server networks | d. | none of the above |
ANS: B
33. Record locking is used to:
a. | store records securely on a server |
b. | prevent multiple users from looking at a document simultaneously |
c. | prevent one user from reading a record that another user is writing to |
d. | none of the above |
ANS: C
34. The software that runs a client-server network must be:
a. | UNIX-based | c. | multitasking |
b. | WINDOWS-based | d. | Novell certified |
ANS: C
35. A "thin" client is:
a. | basically, a PC with no disk drives | c. | same as a "dumb" terminal |
b. | a node that rarely sends data | d. | all of the above |
ANS: A
COMPLETION
1. A LAN is a ____________________ Area Network.
ANS: Local
2. The Internet is a network of ____________________.
ANS: networks
3. In a ____________________ network, all nodes are connected to a central computer.
ANS: star
4. In a ____________________-switched network, users have a dedicated channel for the duration of communications.
ANS: circuit
5. The ____________________ of a network describes how it is physically connected together.
ANS: topology
6. Ring networks often use ____________________-passing.
ANS: token
7. A ____________________ is a short section of a message in digital form.
ANS: packet
8. ____________________ is when two nodes try to seize the same cable at the same time.
ANS: Contention
9. A ____________________ occurs when two nodes transmit simultaneously on the same baseband cable.
ANS: collision
10. In CSMA/CD networks, all collisions must be ____________________.
ANS: detected
11. Carrier-Sense means that a node "listens" for the cable to be ____________________ before using it.
ANS:
quiet
free
unused
available
12. A "____________________" cable links clusters of computers together.
ANS: backbone
13. 100BaseT cables can reliably carry up to ____________________ bits per second.
ANS: 100 mega
14. In CSMA/CD, packets must have a ____________________ length to ensure that collisions are detected.
ANS: minimum
15. In CSMA/CD, the ____________________ of a cable is limited to ensure that collisions are detected.
ANS: length
16. A unique numerical address is provided to a node by its ____________________.
ANS: NIC
17. A 100BaseTX cable is a ____________________ cable.
ANS: fiber-optic
18. Hubs can be ____________________ to form, in effect, one big hub.
ANS: stacked
19. A switch looks at the ____________________ of each incoming packet.
ANS: address
20. The effect of a switch is to greatly reduce ____________________.
ANS: contention
SHORT ANSWER
1. Explain how a network can be a physical bus but a logical ring.
ANS:
A token-passing network sends the token from node to node in a prescribed order. So it doesn't matter how the physical connection is made. It still works like a token-passing ring.
2. What is the key difference between a hub and a switch?
ANS:
A hub sends incoming packets out to all other ports on the hub. A switch sends a packet to a specific port based on the address in the packet.
3. What is the advantage of a CSMA/CD network over a basic star network?
ANS:
If the central computer in a star network fails, the entire network is inoperative. If a node fails in a CSMA/CD network, it can be disconnected and the network still functions.
4. Why do CSMA/CD packets have a minimum size limit?
ANS:
If a packet is too short, nodes at either end of a cable could get on, send a packet, and get off before the packets travel far enough to collide. The collision would not be detected.
5. What is a NIC address, and why is it unique?
ANS:
The address is a long binary number "burned" into a NIC's memory chip at the factory. Each factory uses a different sequence of numbers, so the chances of two NICs on the same network having the same address is extremely small.
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