CN VIVA QUESTIONS

. If a datagram router goes down then _ _ _ _ _ _ _ _ _ _

Ans. only those packets which are queued in the router at that time

will suffer

2. Indatagramsubnetnewrouteischosen__ __ ___ __ __ ___ __ .

ans. for every packet sent

3. ThePSTNisanexampleofa_ ___ __ __ __ __ __ ___ network

Ans.. circuit switched

4. Eachpacketisroutedindependentlyin__ __ __ ___ __ __ __

Ans. datagram subnet

5. For a connection oriented service, we need a _ _ _ _ _ _ _ _ _ _ _

Ans. datagram subnet

6. Which type of switching uses the entire capacity of a dedicated link? 

Ans. message switching

7.In _ _ _ _ _ _ _ _ _ _ _ _ _ _ circuit switching, delivery of data is delayed because data must be stored and retrieved from RAM.

Ans. time division

8. In_ __ __ ___ __ ___ ___,eachpacketofamessageneednotfollowthesamepathfrom sender to receiver.

Ans. datagram approach to packet switching

9. In_ __ __ ___ __ ___ __ _ __ __ __,eachpacketofamessagefollowsthesamepath from sender to receiver.

Ans.circuit switching

10. A permanent virtual circuit involves _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

Ans. Data transfer

11. The set of optimal routes from all sources to a given destination from a tree rooted to the destination is known as _ _ _ _ _ _ _ _ _ _ _ _ _ _

Ans. Sink tree

12. Adaptive routing algorithms get their information from _ _ _ _ _ _ _ _ _ _ _ _ _ _

Ans. from locally, adjacent, external routers

13. If the route from I to J is computed in advance, off line, and downloaded to the routers when the

networkisbootediscalledas__ __ __ ___ ___ __

Ans. Static routing

14. The router algorithm takes the decision to changes the route when _ _ _ _ _ _ _ _ _ _ _ _

Ans.. topology changes

15. If route from router I to router J is computed on line based on the current statistics, then it is called as _ _

_ _ _ _ _ _ _ _ _ _ _ _ _

Ans.. Dynamic routing

16. If the subnet uses virtual circuits internally, routing decisions are made only when a new virtual

circuitisbeingsetup.Thisiscalledas________ _______.

Ans. Session routing

17. _ _ _ _ _ _ _ _ _ _change their routing decisions to reflect changes in the topology.

Ans. Adaptive algorithms

18. If router J is on the optimal path from router I to router K, then the path from J to K along the samerouteis

__ __ _____ ___ _____

Ans. optimal

19. If router J is on the optimal path from router I to router K, then the optimal path from J to K also

fallsalongthesamerouteisknownas_____ ___ ____ ___ __

Ans. Optimality principle

20. ___ _________ ________

donotbasetheirroutingdecisionsonmeasurementsor estimates of the current traffic and topology

Ans.. Nonadaptive algorithms

21. The method of network routing where every possible path between transmitting and receiving DTE is used

is called

Ans.. Packet Flooding

22. In Hierarchical routing for N router subnet, the optimal number of levels is _ _ _ _ _ _ _ _ _.  

Ans.lnN

23. In Hierarchical routing, the routers are divided into what is called as _ _ _ _ _ _ _ _ _ _ _ _ _ _.

Ans.Regions

24. The regions in Hierarchical routing are grouped in to _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.

Ans.Clusters

25. The Clusters in Hierarchical routing are grouped in to _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.

Ans.. Zones

26. 1. If a router sends every incoming packet out only on those lines that are going approximately in

therightdirectionisknownas__ __ ___ _______ ______.

Ans. Selective flooding

27. In shortest path routing algorithm, the path length is measured based on _ _ _ _ _ _ _ _ _ _ _ _ _.

Ans. number of hops

28. Floodingalwayschoosethe______ ___ _______ __.

Ans. Shortest path

29. In military applications where large number of routers may be blown to bits at any instant, we use _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.

Ans. Flooding

30. In distributed applications, it is sometimes necessary to update all the databases concurrently, we use _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.

Ans. Flooding

31. In multicast routing with spanning tree method, a network with n groups, each with an average of m

members, for each group we require _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ .

Ans. m pruned spanning trees must be stored for a total of mn trees

33. To do multicast routing, each router computes a _ _ _ _ _ _ _ _ _ _ _ _ _ . 

Ans.Spanning tree

34. A well -defined groups that are numerically large in size but small compared to the network as a

wholeareusedin __ _______ __ _____ __.

Ans.Multicast routing

35. In__ ______ _______ tosendamulticastmessageahostsendsittothecore,which then does the multicast

along the spanning tree.  

Ans.. Core based Trees

6. Sending a packet to all destinations simultaneously is called _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.

Ans.Broadcasting

37. AnormalFloodingtechniqueisanexampleof____ _________ _____.

Ans.Broadcasting

38. In Broadcast routing, if the router does not know anything all about spanning tree, _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ method is preferred.

Ans.Reverse Path forwarding

39. The method of Broadcast routing in which each packet contains either a list of destinations or a bit map

indicating the desired destinations is _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

Ans.Multidestination

40. Sending a message to a well defined group that are numerically large in size but small compared to the

network as a whole is called _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ .

Ans.Multicasting

41. In link state routing, after the construction of link state packets new routes are computed using _ _ _ _ _ _ _ _

_ _ _ _ .

Ans.. Dijkstra's algorithm

43. Count-to-Infinityproblemoccursin______ ______ ___]

Ans.distance vector routing

44. In distance vector routing algorithm, each router maintains a separate routing table with the following

entries .

Ans.preferred output line, estimated time

45. Linkstatepacketsarebuiltin _______ ___.

Ans. distance vector routing

46. In which routing method do all

Ans.. Link State

47. In distance vector routing algorithm, the routing tables are updated _ _ _ _ _ _ _ _ _ _ _ _ _ _ .

Ans.by exchanging information with the neighbors

48. Distance vector routing algorithm is implemented in Internet as _ _ _ _ _ _ _ _ _ _ _ _ _ _ .

Ans.RIP

49. Which of the following routing algorithm takes into account the current network load.

Ans.distance vector routing

50. Indistancevectorroutingthedelaymetricis __________ _______

Ans. queue length

51. The processes that keep track of hosts whose home is in the area, but who currently visiting another area

is _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ .

Ans.Home agent

52. In AODV routing algorithm for MANETs, the route is discovered at time _ _ _ _ _ _ _ _ _ _ _ _ _ .

Ans.. when there is a need for route by the host

53. Military vehicles on a battlefield with no existing infrastructure will deploy _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

network.

Ans. MANET

54. The network in which all the nodes are symmetric and there is no central control or hierarchy is _ _ _ _ _ _ _ _

_ _ _

Ans.Peer-to-Peer

55. What is the type of network in which the topology change from time to time?

Ans.MANET

56. The processes that keep track of all mobile hosts visiting the area is _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ .

Ans.Foreign agent

57. The hosts which are basically stationary hosts who move from one fixed site to another from time to time but

use the network only when they are physically connected to it are called _ _ _ _ _ _ _ _ _ _ _ .

Ans.Migratory hosts

58. The hosts who compute on the run and want to maintain their connections as they move around _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ .

Ans. Mobile hosts

59. What is the type of network in which the routers themselves are mobile?

Ans.Mobile Ad hoc Network

60. What is the routing algorithm used in MANETs?

Ans. Ad hoc On -demand Distance Vector Protocol

61. Why probe packets are transmitted in the network?

Ans. to know about the congestion

62. If the source deduces the existence of congestion by making local observations,such as the time needed for

acknowledgements to come back is called as _ _ _ _ _ _ _ _ _ _ _ .

Ans. Implicit feedback algorithm

63. The solution to decrease the load on the network when congestion occurs is _ _ _ _ _ _ _ _ _ _ .

Ans.denying service to the users

64. In open loop congestion control techniques, the decisions are based on the _ _ _ _ _ _ _ _ _ _ .

Ans.without regard to the current state of the network

65. In closed loop congestion control techniques, the decisions are based on the _ _ _ _ _ _ _ _ _ _ .

Ans.concept of a feedback loop

66. When too many packets are present in the subnet, and performance degrades then it leads to _ _ _ _ _ _ _ _

_ _ _ _ .

Ans.Congestion

67. What is it goal of congestion control?

Ans.. making sure that subnet is able to carry the offered traffic

68. The service of open loop congestion control technique is _ _ _ _ _ _ _ _ _ _ _ .

Ans.when to accept new traffic

69. The service of closed loop congestion control technique is _ _ _ _ _ _ _ _ _ _ _ .

Ans. monitor the system to detect when and where congestion occurs

70. The solution to increase the capacity when congestion occurs

is _ _ _ _ _ _ _ _ _ _ _ _ _ .

Ans. splitting traffic over multiple routes

71. When routers are being inundated by packets that they cannot handle, they just throw them away is

known as _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ .

Ans.Load shedding

72. If f is the sample instantaneous line utilization, a is the constant that determines how fast the router forgets

recent history and u is the recent utilization of the line then the formula to update u is _ _ _ _ _ _ _ _ _ _ _ _ .

73. The choke packet is send back to the source if _ _ _ _ _ _ _ _ _ .

Ans. The utilization factor u moves above the given threshold

74. When the source host receives the choke packet, then the source _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ .

Ans. reduces the traffic generation

75. If the buffer fills and a packet segment is dropped, then dropping all the rest of the segments from that

packet, since they will be useless anyway is called _ _ _ _ _ _ _ _ _ _ _ _ _ _

Ans.Tail dropping

76. Timeoutdeterminationpolicyisusedin___ __________ ____.

Ans. transport layer

77. Flowcontrolpolicyisimplementedin_____ __________ _.

Ans. transport layer

78. Packet discard policy is implemented in _ _ _ _ _ _ _ _ _ _ _ _ _ _

Ans.Network layer

79. 4. For applications such as audio and video streaming, the variation in the packet arrival times is called _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ .

Ans. Jitter

80. Sending of a IP packet from host 1 to host 2 where both are of same LAN but the packet is transferred through

different intermediate LANs is called _ _ _ _ _ _ _ _ _ _ _ _ _ _ .

Ans. Tunneling

81. The type of fragmentation in which packet is fragmented at the source host and reassembly is done only

at destination host is _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ .

Ans.nontransparent fragmentation

82. Firewalls are used for___ _______

Ans. security

83. To translate the message semantics from one format to other, _ _ _ _ _ _ _ _ _ _ is used

Ans. application gateway

84. The routing algorithm within each network is _ _ _ _ _ _ _ _ _ _ _ _ _ _ .

Ans.Interior gateway protocol

85. In _ _ _ _ _ _ _ _ case higher bandwidth can be achieved.

Ans. connectionless networks

86. Fragmentationmeans_________ _______ __

Ans.breaking large packet into small packets

87. Bridgesareusedat________ ___layer

Ans.MAC layer

88. Routersareusedat_ __________layer

Ans. Network

89. Gatewaysareusedat_ ___ ___ _____layer

Ans.Application

90. Which type of ATM service is used for regroup timing requirements?

Ans.. constant bit rate

91. Which of the following assertions is FALSE about the Internet Protocol(IP)?

Ans. It is possible for a computer to have multiple IP addresses

92. _ _ _ _ _ _ _ _ _ _ _ protocol is used for constant bit rate.

Ans.AAL1

93. While booting the system the IP address is _ _ _ _ _ _ _ _ _ _ _ .

Ans.0.0.0.0

94. In ATM network _ _ _ _ _ _ _ _ _ message is used by a source host to set up a connection.

Ans.SET UP

95. How many class A, B and C networks IDs can exist

Ans.2,113,658

96. Which of the following TCP/IP internet protocol, a diskless machine uses to obtain its IP address from a

server

Ans.RARP

97. Theprotocolusedtotesttheinternetis__ _______ _______.

Ans.. ICMP

98. Which IP address class has few hosts per network?

c. class C

99. TheIPaddresswith127aabbccisusedfor_ _________ ___ __.

Ans.loop back testing

100. What type of addressing is specifically used by the transport layer?

Ans. application program port address