Indian Institute of Technology Mumbai (IIT-M) 2005 M.E Information Technology GATE IT - Question Paper

negligible. To get a channel efficiency of at lowest 50°h, the minimum frame size should be
(A) 80 bytes
(B) 80 bits
(C) 160 bytes
(D) 160 bits
73. On a TCP connection, current congestion window size is Congestion Window = four KB. The
window size advertised by the received is Advertise Window = six KB. The last byte sent by the
sender is LastByteSent = 10240 and the last byte acknowledged by the receiver is
LastByteAcked = 8192. The current window size at the sender is:
(A) 2048 bytes
(B) 4096 bytes
(C) 6144 bytes
(D)8192 bytes
74. In a communication network, a packet of length L bits takes link Li with a probability of Pi
or link L2 with a probability of P2. Link Li and L2 have bit fault probability of b1 and b2
respectively. The probability that the packet will be received without fault via either Li or L2
is:
(A) (i_b1)Lp1+(i_b2)Lp2 (B) [i_(b1+b2)P1P2
(C) (1—b1 )L (1 — b2 )L p1p2 (D) i — (bi’-p, + b21- p)
75. In a TDM medium access control bus LAN, every station is assigned 1 time slot per cycle
for transmission. presume that the length of every time slot is the time to transmit 100 bits plus
the end-to-end propagation delay. presume a propagation speed of 2xiO8m/sec. The length of
the LAN is one km with a bandwidth of 10 Mbps. The maximum number of stations that can be

allowed in the LAN so that the throughput of every station can be Mbps is:
(A) 3
(B) 5
(C) 10
(D)20
76. A company has a class C network address of 204.204.204.0. It wishes to have three
subnets, 1 with 100 hosts and 2 with 50 hosts every. Which 1 of the subsequent choices
represents a feasible set of subnet address/subnet mask pairs?
(A) 204.204.204.128/255.255.255.192
204.204.204.0/255.255.255.128
204.204.204.64/255.255.255.128
(B) 204.204.204.0/255.255.255.192
204.204.204.192/255.255.255.128
204.204.204.64/255.255.255.128
(C) 204.204.204.128/255.255.255.128
204.204.204.192/255.255.255.192
204.204.204.224/255.255.255.192
(D) 204.204.204.128/255.255.255.128
204.204.204.64/255.255.255.192
204.204.204.0/255.255.255.192
77. presume that “hostl.mydomain.dom” has an IP address of 145.128.16.8. Which of the

Earning:   Approval pending.