71. An attacker sits between customer and Banker, and captures the information from the customer and retransmits to the banker by altering the information. This attack is called as ..............
a. Masquerade Attack
b. Replay Attack
c. Passive Attack
d. Denial of Service Attack
Answer: (b).Replay Attack

72. Match the following Layers and Protocols for a user browsing with SSL:

a. Application layer i. TCP
b. Transport layer ii. IP
c. Network layer iii. PPP
d. Datalink layer iv. HTTP

Codes: a b c d
a. iv i ii iii
b. iii ii i iv
c. ii iii iv i
d. iii i iv ii
Answer: (a).iv i ii iii

73. The maximum size of the data that the application layer can pass on to the TCP layer below is .........
a. 2^16 bytes
b. 2^16 bytes + TCP header length
c. Any size
d. 2^16 bytes - TCP header length
Answer: (c).Any size

74. A packet whose destination is outside the local TCP/IP network segment is sent to ..............
a. File server
b. DNS server
c. DHCP server
d. Default gateway
Answer: (d).Default gateway

75. Distance vector routing algorithm is a dynamic routing algorithm. The routing tables in distance vector routing algorithm are updated ...........
a. automatically
b. by server
c. by exchanging information with neighbor nodes
d. with back up database
Answer: (c).by exchanging information with neighbor nodes

76. In link state routing algorithm after the construction of link state packets, new routes are computed using:
a. DES algorithm
b. Dijkstra's algorithm
c. RSA algorithm
d. Packets
Answer: (b).Dijkstra's algorithm

77. Suppose there are n stations in a slotted LAN. Each station attempts to transmit with a probability P in each time slot. The probability that only one station transmits in a given slot is ..................
a. nP(1-P)^n-1
b. nP
c. P(1-P)^n-1
d. n^P(1-P)^n-1
Answer: (a).nP(1-P)^n-1

78. Station A uses 32 byte packets to transmit messages to station B using sliding window protocol. The round trip delay between A and B is 40 milli seconds and the bottleneck bandwidth on the path between A and B is 64 kbps. The optimal window size of A is
a. 20
b. 10
c. 30
d. 40
Answer: (b).10

79. Let G(x) be generator polynomial used for CRC checking. The condition that should be satisfied by G(x) to correct odd numbered error bits, will be:
a. (1+x) is factor of G(x)
b. (1-x) is factor of G(x)
c. (1+x^2) is factor of G(x)
d. x is factor of G(x)
Answer: (a).(1+x) is factor of G(x)

80. In a packet switching network, if the message size is 48 bytes and each packet contains a header of 3 bytes. If 24 packets are required to transmit the message, the packet size is ................
a. 2 bytes
b. 1 byte
c. 4 bytes
d. 5 bytes
Answer: (d).5 bytes