COMPUTER NETWORKS
Part-1
1. Protocols are?[A] Agreements on how communication components and DTE's are to communicate
[B] Logical communication channels for transferring data
[C] Physical communication channels sued for transferring data
[D] None of above
2. Which data communication method is used to transmit the data over a serial communication link?
[A] Simplex
[B] Half-duplex
[C] Full duplex
[D] All of above
3. The method of communication in which transaction takes place in both directions,but only in one direction at a time, is called ?
[A] Simplex
[B] Four wire circuit
[C] Full duplex
[D] Half-duplex
4. In communication satellite, multiple repeaters are known as?
[A] Detectors
[B] Modulators
[C] Stations
[D] Transponders
5. Error detection at the data link layer is achieved by?
[A] Bit stuffing
[B] Cyclic redundancy codes
[C] Hamming codes
[D] Equalization
6. Loss in signal power as light travels down the fiber is called?
[A] Attenuation
[B] Propagation
[C] Scattering
[D] Interruption
7. The topology with highest reliability is ?
[A] Bus topology
[B] Star topology
[C] Ring Topology
[D] Mesh Topology
8. Baud means?
[A] The number of bits transmitted per unit time
[B] The number of byted transmitted per unit time
[C] The rate at which the signal changes
[D] None of above
9. In OSI model dialogue control and token management are responsibilities of ?
[A] Session Layer
[B] Network layer
[C] Transport layer
[D] Data link layer
10. Under mark parity,each parity bit is?
[A] Alternated between 0 and 1
[B] Always set to 0
[C] Always set to 1
[D] Not used
11. How long is an IPv6 address?
[A] 32 bits
[B] 128 bits
[C] 128 bytes
[D] 64 bits
12. You have 10 users plugged into a hub running 10Mbps half-duplex. There is a server connected to the switch running 10Mbps half-duplex as well. How much bandwidth does each host have to the server?
[A] 100 kbps
[B] 10 Mbps
[C] 1 Mbps
[D] 2 Mbps
13. How often are BPDUs sent from a layer 2 device?
[A] Every 2 seconds
[B] Never
[C] Every 10 minutes
[D] Every 30 seconds
14. Which router command allows you to view the entire contents of all access lists?
[A] show all access-lists
[B] show access-lists
[C] show ip interface
[D] show interface
15. What protocols are used to configure trunking on a switch?
[A] VLAN Trunking Protocol
[B] VLAN
[C] 802.1Q
[D] ISL
16. How many collision domains are created when you segment a network with a 12-port switch?
[A] 1
[B] 12
[C] 5
[D] 2
17. Which protocol does Ping use?
[A] TCP
[B] ARP
[C] ICMP
[D] BootP
18. What PPP protocol provides dynamic addressing, authentication, and multilink?
[A] NCP
[B] HDLC
[C] X.25
[D] LCP
19. What is a stub network?
[A] A network that has only one entry and exit point.
[B] A network with only one entry and no exit point.
[C] A network with more than one exit point.
[D] A network with more than one exit and entry point.
20. Which of the following services use TCP?
[A] DHCP
[B] SMTP
[C] FTP
[D] TFTP
[E] HTTP
21. Which of the following is private IP address?
[A] 192.168.24.43
[B] 168.172.19.39
[C] 172.15.14.36
[D] 12.0.0.1
22. Which class of IP address provides a maximum of only 254 host addresses per network ID?
[A] Class A
[B] Class B
[C] Class C
[D] Class D
[E] Class E
23. In dial up remote access a client uses the ---- to create a physical connection to a part on a remote access server of the private network.
[A] Public telephone network
[B] Bank�??s branch network
[C] Private network
[D] Public local network
24. Which of the following devices is a PC component that connects the computer to the network?
[A] Bridge
[B] NIC
[C] DNS Server
[D] Gateway
25. Which of the following devices modulates digital signals into analog signals that can be sent over traditional telephone lines?
[A] Router
[B] Gateway
[C] Switch
[D] Modem
26. Which of the following devices takes data sent from one network device and forwards it to all devices on the network regardless of the intended recipient?
[A] DNS Server
[B] Switch
[C] Hub
[D] Gateway
27. Which of the following devices takes data sent from one network device and forwards it to the destination node based on MAC address?
[A] Hub
[B] Switch
[C] Gateway
[D] Modem
28. Although they've fallen out of favor, which of the following devices is used to connect different network segments and manage the traffic between them?
[A] Bridge
[B] Hub
[C] Gateway
[D] Repeater
29. Which of the following devices direct network traffic based not by MAC addresses but by software-configured network addresses?
[A] Router
[B] Hub
[C] Bridge
[D] NIC
30. Which of the following network devices/systems translates data from one format to another?
[A] Hub
[B] DHCP Server
[C] Gateway
[D] NIC
31. Which of the following terms is used to describe a hardware- or software-based device that protects networks from outside threats?
[A] NIC
[B] Gateway
[C] Firewall
[D] Hub
32. Which of the following devices assigns IP address to devices connected to a network that uses TCP/IP?
[A] DHCP Server
[B] NIC
[C] Gateway
[D] Hub
33. Which of the following devices translates hostnames into IP addresses?
[A] DNS Server
[B] Hub
[C] DHCP Server
[D] Firewall
34. Switch is a Device of _________ Layer of OSI Model.
[A] Network Layer
[B] Data Link Layer
[C] Application Layer
[D] Session Layer
35. HUB is a _________ Device and Switch is a ________ Device.
[A] Unicast, Multicast
[B] Malticast, Unicast
[C] Broadcast, Unicast
[D] None of Above
36. Star Topology is Based On a Central Device that can be __________ ?
[A] HUB
[B] Switch
[C] Only A
[D] Both A and B
37. The data on a DVD is held in the form of ....... on the disc.
[A] small pits and bumps
[B] small bits
[C] small bytes
[D] None of These
38. Repeaters operate similar to ……… which also just create electronic nodes to extend the cable length.
a) Ethernet hubs b) Bridges c) Ethernet switches d) Connectors e) Hoppers
39. Fast ethernet ……..
a) uses only optical-fiber so it is really fast
b) is not backward compatible with old ethernet.
c) runs 2000 meters with twisted pair cable d) switches are full-duplex
e) hubs are 10 Mbps
40. Which one of the following is incorrect?
a) Full-duplex means simultaneous transmission and reception.
b) Simplex device cannot talk back.
c) One of the reliability measures of networks is the robustness in catastrophe.
d) On a dedicated link there can only be two devices.
e) Half-duplex means only half of the cable is duplex.
41. ………. layer handles the physical addressing of communicating devices. a) Physical b) Logical c) Data link d) Network e) Transport
42. Gateways are similar to routers …………………………..
a) in the way they route incoming packets.
b) that they both use the same OSI layers. c) requiring ethernet addresses on all ports. d) except when working with IP packets.
e) which can be thought of advanced switches.
43. Class of an IP address can be determined from ………. and determines the ………. a) the first 3 quads -- network part.
b) the number of netmask bits -- network address.
c) the routing table -- destination IP address.
d) the first 4 bits -- number of hosts in the network.
e) the host bits -- netmask.
Part 2
1. What is the name of the algorithm used in CSMA/CD networks
in order to avoid repeated collisions?
a) collision avoidance b) crash prevent c) exponential
back-off d) exponential collisions e) collision detection
2. In which of the following, are the received cells
guaranteed to be in order?
a) ATM b) Wireless ethernet c) TCP/IP d) ISDN e) ADSL
3. Multimode fibers have more …......... than single
mode fibers at the receiving end. a) light b) dispersion c) speed d)
wavelength e) cable length
4. What is the signal that travels around the
token-ring and carries data called?
a) Packet b) cell c) frame d) token e) bus
5. What is the name of the fixed route established at
the time of initial connection setup in ATM networks?
a) connection network b) data route c) virtual circuit
d) ring e) VPN
6. What is the maximum length of Cat-5 cable in a fast
ethernet network?
a) 180 m b) 200 m c) 1000 m d) 1200 m e) 100 m
7. Which one of the following is the lowest bit rate in
ATM networks?
a) 155 Mbps b) 622 Mbps c) 1544 kbps d) 1000 Mbps e) 10
Mbps
8. QAM uses different ……… in order to transmit multiple
bits in one signal change. a) frequencies b) pulses c) bit-rates d) amplitude-phase
e) bits
9. Higher capacity channel in BRI service of ISDN is
called ……. channel?
a) DSL b) B c) PRI d) NT1 e) D
10. What is the lowest discrete channel in discrete
multitone signaling of DSL used for?
a) control b) voice c) data d) channel allocation e)
unused
11. What does A in ADSL stand for?
a) Alternative b) Asynchronous c) Attenuated d) Asymmetric
e) Additive
12. What is the type of operation in wireless ethernet
when a management/arbitration device exists?
a) point coordination b) distributed coordination c)
managed arbitration d) management point e) access point
13. What does FHSS stand for in wireless communication?
a) Fairly Harmonic Signal Sink b) Frequency Halving Signal
Spectrum
c) Frequency Hopping Spread Spectrum d) Fast High
Simple Solution e) Full Harmonic Signal Spectrum
14. Concatenation of multiple frames for a single
transmission in gigabit ethernet is called ….
a) carrier extension b) combination c) flow control d) full
frame
e) frame bursting
15. How many bits are used for addressing in gigabit
ethernet?
a) 64 bits b) 48 bits c) 32 bits d) variable e) 128
bits
16. What is the maximum length of 100Base-FX segment?
a) 2000 m b) 100 m c) 185 m d) 5000 m e) 200 m
17. What is the netmask of the gateway interface in a
sub-C network where only 14 hosts may exist and IP address of one of the hosts
is 193.145.122.76?
a) 255.255.255.224 b) 193.145.122.15 c) 255.255.255.0
d) 255.255.255.240 e) 193.145.122.240
18. What is the name of routing type in which every
incoming packet is sent to every neighbor router except the one from which the
packet came?
a) distribution b) multicast c) link-state d) shortest-path e)
flooding
19. The shortest routes from a router to all other
routers make up a …….. because of the optimality principle.
a) short-node b) cut-tree c) sink-tree d) binary-tree
e) tentative-route
20. What is the main difference of dynamic routing
compared to static one?
a) real-time connection establishment b) dynamic
routing table-updates c) dynamic behavior against flooding d) multiple output
routes
e) dynamic
change of hardware position
Part 3
1. Which of the following does not
have a Data-Link Layer?
a) Router b) Gateway c) Switch d)
Bridge e) Repeater
2. How many network bits
does125.140.128.16 have?
a) 8 b) 16 c) 24 d) 32 e) 1
3. How many cable segments
does a fully connected network of 10 hosts have?
a) 100 b) 45 c) 90 d) 10 e)
81
4. Which specifications the
Physical Layer deals with?
a) Physical-Electrical b)
Logical-Electrical c) Capacity-Load d) Routing-Switching e) Delivery-CSMA/CD
5. How many bytes are
ethernet addresses in CSMA/CD networks?
a) 16 b) 5 c) 6 d) 48 e) 4
6. IP address of a host is
found using its name by the service named ………………
a)
Routing service b) Encription service c) Network Layer d) Name
service e) ARP service
7. How many pins of RJ-45
connectors are required when used in 10Base-T networks?
a)
8 b) 4 c) 2 d) 6 e) 3
9. What is a broadcast IP address?
a) IP address of a broadcasting
host b) IP address with all hosts bits set to zero
c) IP address with all network bits
set to 1 d) IP address with all host bits set to 1 e) IP address with
last byte set to 255
10. Which OSI layer deals
with physical addressing of the device?
a) Ethernet L. b) IP L. c) Address
L. d) Physical L. e) Data Link L.
11. Which of the following
can be a measure for the reliability of a computer network?
a) Mean time between
failures b) Implemented protocol
c) Type of hosts d) Connections per
unit time e) Protection software used on hosts
12. A dedicated physical
link between two hosts is said to be?
a) Mesh Lin b) Shared link c)
Simplex d) Point-to-point e) Duplex
13. Which of the following
is a disadvantage for networks with bus topology?
a) Less cabling than ring b) Needs
a central device c) Cheaper connectors d) It is collision-free e) Cable
faults down entire network
14. Which of the following is not an advantage of fiber-optic media
for communication?
a) Has high bandwidth b) Has low
EMI c) Has high security d) Has low attenuation e) Requires high-tech
equipment
15. In a router, what is the name of the structure that
tells where to deliver IP-packets?
a) Router address b) Routing table c) Delivery table d)
Status table e) Default entry table
16. Which of the following is not one of the seven OSI
layers?
a) Adaptation b) Session c) Network d) Transport e)
Presentation
17. What is the purpose of preamble bits in an ethernet
frame?
a)
Initialization of ARP b) Pre-bit counting c) Synchronization d) Error
checking e) Destination address
PRACTICE QUESTIONS WITH KEY
Fill In The Blanks: 1. Number of links to connect n nodes in a mesh topology is = _______.
2. Mesh Topology is _______ flexible and has a ________ expandability
3. In BUS topology, at each end of the bus is a ____________, which absorbs any signal, removing it from the bus.
4. In BUS topology, One can easily add any new node or delete any node with-out affecting other nodes; this makes this topology easily _____________.
5. _________ and ______________ will force a maximum length of shared medium which can be used in BUS topology.
6. The two alternatives for the operation of the central node in STAR topology are:
__________ and ___________.
7. In Ring Topology, the links are _____________; that is, data are transmitted in __________ direction only and all are oriented in the same way
8. In Ring Topology, Repeater works in 3 modes: ____________, _____________ and ______________.
9. ___________ topology can be considered as an extension to BUS topology.
10. ______________ is suitable for use in star and ring topologies
11. Coaxial cable is suitable for use in __________ topology.
Solutions:
1. n(n-1)/2
2. not, poor
3. terminator
4. expandable.
5. Delay, signal unbalancing
6. repeater, switch
7. unidirectional, one
8. Listen, Transmit, By-Pass
9. Tree
10. Twisted pair
11. BUS
Fill In The Blanks:
1. The basic question which has to be answered by the medium-access control techniques is “How Goes ________”?
2. In _______________ technique, each node gets a chance to access the medium by rotation.
3. The key issues involved in MAC protocol are - Where and ______ the control is exercised.
4. ‘Where’ refers to whether the control is exercised in a _____________ or ______________ manner.
5. The _______________ techniques can be broadly categorized into three types; Round-Robin, Reservation and___________.
6. ______________ is an example of centralized control and ______________ is an example of distributed control
Version 2 CSE IIT, Kharagpur 7. In Polling technique, if there is no data, usually a ______________ message is sent back.
8. In pure ALOHA, channel utilization, expressed as throughput S, in terms of the offered load G is given by _________
9. In slotted ALOHA, a maximum throughput of ________ percent at 100 percent of offered load can be achieved, while it is ______ percentage for pure ALOHA.
10. _________________ is abbreviated as CSMA/CD and is also known as .__________
11. To achieve stability in CSMA/CD back off scheme, a technique known as ______________ is used
Solutions:
1. Next
2. token passing
3. How4. centralized, distributed
5. asynchronous, Contention
6. Polling, token passing
7. poll reject
8. S=Ge-2G
9. 37, 18
10. Carrier Sensed Multiple Access with Collision Detection, Listen-While-Talk .
11. binary exponential back off
Fill In The Blanks :
1. The 802.2 standard describes the ____________, which is the upper part of the data link layer.
2. LLC offers three types services: Unreliable datagram service, ________________ and _______________.
3. IEEE 802 bundle also includes a MAN standard IEEE 802.6 which is also known as ______________.
4. 100Base-T2 means _______________________________
5. 100 Mbps, baseband, long wavelength over optical fiber cable will be abbreviated as ________________
6. Ethernet uses __________ encoding
Answers:
1. LLC (logical link layer)
2. Acknowledged datagram service, Reliable connection oriental service
3. Distributed Queue Dual Bus (DQDB)
4. 100 Mbps, baseband, over two twisted-pair cables
5. 1000Base F
6. Bi-phase Manchester
Fill In The Blanks:
1. Originally, ______________ developed Token Ring network in the ________.
2. A disadvantage of this topology is that it is vulnerable to _________ or _____ failure.
3. Unlike CSMA/CD networks (such as Ethernet), token-passing networks are ________________, which means that it is possible to calculate the maximum time that will pass before any end station will be capable of transmitting.
4. Token Ring frames have two fields that control priority: ___________ and the ___________field.
Version 2 CSE IIT, Kharagpur 5. In Token Ring inside the wire center, _____________ are used to isolate a broken wire or a faulty station.
6. The Mac sublayer in Token BUS consists of four major functions: ____________, the access control machine (ACM), ______________________and .____________
7. ___________ determines when to place a frame on the bus, and responsible for the maintenance of the logical ring including the error detection and fault recovery.
Answers:
1. IBM, 1970
2. link, station
3. deterministic
4. the priority field, reservation
5. bypass relays
6. the interface machine (IFM), the receiver machine (RxM), the transmit machine (TxM).
7. Access control machine (ACM)
Fill In The Blanks:
1. The high speed LANs that have emerged can be broadly categorized into three types______________, successors of Ethernet and ___________.
2. ATM, fiber channel and the Etherswitches comes under high speed LANs based on _______________.
3. ______________________ is abbreviated as FDDI.
4. FDDI over copper is referred to as __________________________.
5. The basic topology for FDDI is _____________________.
6. An _____________ provides continuous dual-ring operation if a device on the dual ring fails
7. Each data frame in FDDI carries up to ____________ bytes.
8. FDDI gives fair and equal access to the ring by using a _________ protocol.
9. FDDI implements MAC using three timers namely: ________________, Token Rotation Timer (TRT) and ___________________
10. Token holding Timer (THT), which determines .___________________________
11. The frame status (FS) byte is set by the ____________ and checked by the _______________ station which removes its frame from the ring and generates another token. 12. When the frame returns to the sending station, that station removes the frame from the ring by a process called ___________.
13. The physical layer is divided into two sub layers - _______ and ______
Solutions.
1. based on token passing, based on switching technology.
2. based on switching technology.
3. Fiber Distributed Data Interface
4. Copper-Distributed Data Interface (CDDI).
5. dual counter rotating rings
6. optical bypass switch
7. 4500
8. timed token
9. Token holding Timer (THT), Valid Transmission Timer (VTT)
10. how long a station may continue once it has captured a token
11. destination, source
12. stripping
13. PMD, PHY
Fill In The Blanks:
1. Switched Ethernet gives dedicated 10 Mb/s bandwidth on __________ of its ports.
2. In Ethernet (IEEE 802.3) the topology, though physically is _________ but logically is BUS. i.e. the collision domain of all the nodes in a LAN is ._________
3. In Switched Ethernet, collision domain is separated. Hub is replaced by a .________
4. There are two techniques used in the implementation of Ethernet switches: _____________ and ________
5. IEEE has designed two categories of Fast Ethernet: ____________ and .__________
6. 100-Base-X itself is divided into two: __________ and __________
7. The Gigabit Ethernet Alliance was formed in ___________ by ______ companies.
8. The GMII is the interface between the ________ layer and the ___________ layer.
9. ________, a sublayer of GMII provides a medium-independent means for the PCS to support various serial bit-oriented physical media.
10. Packet Bursting is an extension of ______________. Packet Bursting is "Carrier Extension plus a ____________".
Solutions:
1. each
2. star, common
3. switch
4. store-and-forward, cut-through
5. 100Base-X, 100Base-T4
6. 100Base-TX, 100base-FX.
7. May 1996, 11
8. MAC, Physical
9. PMA (Physical Medium Attachment)
10. Carrier Extension, burst of packets