Transport Layer Protocol

Question 1
Consider the three-way handshake mechanism followed during TCP connection establishment between hosts P and Q. Let X and Y be two random 32-bit starting sequence numbers chosen by P and Q respectively. Suppose P sends a TCP connection request message to Q with a TCP segment having SYN bit =1, SEQ number =X, and ACK bit =0. Suppose Q accepts the connection request. Which one of the following choices represents the information present in the TCP segment header that is sent by Q to P?
A
SYN bit =1, SEQ number =X+1, ACK bit =0, ACK number =Y, FIN bit =0
B
SYN bit =0, SEQ number =X+1, ACK bit =0, ACK number =Y, FIN bit =1
C
SYN bit =1, SEQ number =Y, ACK bit =1, ACK number =X+1, FIN bit =0
D
SYN bit =1, SEQ number =Y, ACK bit =1, ACK number =X, FIN bit =0
GATE CSE 2021 SET-2   Computer Network
Question 2
Consider two hosts P and Q connected through a router R. The maximum transfer unit (MTU) value of the link between P and R is 1500 bytes, and between R and Q is 820 bytes.
A TCP segment of size 1400 bytes was transferred from P to Q through R, with IP identification value as 0x1234. Assume that the IP header size is 20 bytes. Further, the packet is allowed to be fragmented, i.e., Don't Fragment (DF) flag in the IP header is not set by P.
Which of the following statements is/are correct?
[MSQ]
A
Two fragments are created at R and the IP datagram size carrying the second fragment is 620 bytes.
B
If the second fragment is lost, R will resend the fragment with the IP identification value 0x1234.
C
If the second fragment is lost, P is required to resend the whole TCP segment.
D
TCP destination port can be determined by analysing only the second fragment.
GATE CSE 2021 SET-1   Computer Network
Question 3
A TCP server application is programmed to listen on port number P on host S. A TCP client is connected to the TCP server over the network.
Consider that while the TCP connection was active, the server machine S crashed and rebooted. Assume that the client does not use the TCP keepalive timer. Which of the following behaviors is/are possible?
[MSQ]
A
If the client was waiting to receive a packet, it may wait indefinitely.
B
The TCP server application on S can listen on P after reboot.
C
If the client sends a packet after the server reboot, it will receive a RST segment.
D
If the client sends a packet after the server reboot, it will receive a FIN segment.
GATE CSE 2021 SET-1   Computer Network
Question 4
Checksum field in TCP header is
A
ones complement of sum of header and data in bytes
B
ones complement of sum of header, data and pseudo header in?16?bit words
C
dropped from IPv6 header format
D
better than md5 or sh1 methods
ISRO CSE 2020   Computer Network
Question 5
The persist timer is used in TCP to
A
To detect crashes from the other end of the connection
B
To enable retransmission
C
To avoid deadlock condition
D
To timeout FIN_Wait1 condition
ISRO CSE 2020   Computer Network
Question 6
Consider a TCP connection between a client and a server with the following specifications; the round trip time is 6 ms, the size of the receiver advertised window is 50 KB, slow-start threshold at the client is 32 KB, and the maximum segment size is 2 KB. The connection is established at time t=0. Assume that there are no timeouts and errors during transmission. Then the size of the congestion window (in KB) at time t+60 ms after all acknowledgements are processed is _______
A
22
B
44
C
18
D
36
GATE CSE 2020   Computer Network
Question 7
Assuming that for a given network layer implementation, connection establishment overhead is 100 bytes and disconnection overhead is 28 bytes. What would be the minimum size of the packet the transport layer needs to keep up, if it wishes to implement a datagram service above the network layer and needs to keep its overhead to a minimum of 12.5%. (ignore transport layer overhead)
A
512 bytes
B
768 bytes
C
1152 bytes
D
1024 bytes
ISRO CSE 2018   Computer Network
Question 8
Consider a long-lived TCP session with an end-to-end bandwidth of 1 Gbps (= 10^{9} bits-per-second). The session starts with a sequence number of 1234. The minimum time (in seconds, rounded to the closest integer) before this sequence number can be used again is _______.
A
35
B
40
C
50
D
30
GATE CSE 2018   Computer Network
Question 9
Consider the following statements regarding the slow start phase of the TCP congestion control algorithm. Note that cwnd stands for the TCP congestion window and MSS denotes the Maximum Segment Size.

(i) The cwnd increases by 2 MSS on every successful acknowledgment.
(ii) The cwnd approximately doubles on every successful acknowledgement.
(iii) The cwnd increases by 1 MSS every round trip time.
(iv) The cwnd approximately doubles every round trip time.

Which one of the following is correct?
A
Only (ii) and (iii) are true
B
Only (i) and (iii) are true
C
Only (iv) is true
D
Only (i) and (iv) are true
GATE CSE 2018   Computer Network
Question 10
Match the following:
A
P-III, Q-IV, R-II, S-I
B
P-II, Q-I, R-IV, S-III
C
P-IV, Q-I, R-II, S-III
D
P-IV, Q-I, R-III, S-II
GATE CSE 2018   Computer Network
There are 10 questions to complete.

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