GATE||Computer Network || TCP UDP & IP || PYQ ( 2010 TO 2025)

Consider the data transfer using TCP over a 1 Gbps link. Assuming that the maximum segment lifetime (MSL) is set to 60 seconds, the minimum number of bits required for the sequence number field of the TCP header, to prevent the sequence number space from wrapping around during the MSL is ___________. [GATE || 2022 NAT || 2-mark]

The maximum number of IPv4 router addresses that can be listed in the record route (RR) option field of an IPv4 header is __________. [ GATE||2017||Set 2|| NAT || 1-mark ]

Consider a TCP client and a TCP server running on two different machines. After completing data transfer, the TCP client calls close to terminate the connection and a FIN segment is sent to the TCP server. Server-side TCP responds by sending an ACK, which is received by the client-side TCP. As per the TCP connection state diagram (RFC 793), in which state does the client-side TCP connection wait for the FIN from the server-side TCP? [GATE||2017|| Set 1 || MCQ || 1-mark ]

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 [GATE||2018 NAT || 1-mark]

Consider the following statements regarding the slow start phase of the TCP congestion control algorithm. Note the 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 acknowledgment.
(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? [GATE||2018 MCQ || 1-mark]

Match the following:

Field
P. UDP Header’s Port Number
Q. Ethernet MAC Address
R. IPv6 Next Header
S. TCP Header’s Sequence Number

Lengths in bits

i. 48
ii. 8
iii. 32
iv. 16 [GATE|| 2018 MCQ || 1-mark]

Consider three machines M, N, and P with IP addresses 100.10.5.2, 100.10.5.5, and 100.10.5.6 respectively. The subnet mask is set to 255.255.255.252 for all the three machines. Which one of the following is true? [GATE|| 2019 MCQ || 2-mark]

An organization requires a range of IP addresses to assign one to each of its 1500 computers. The organization has approached an Internet Service Provider (ISP) for this task. The ISP uses CIDR and serves the requests from the available IP address space 202.61.0.0/17. The ISP wants to assign an address space to the organization which will minimize the number of routing entries in the ISP’s router using route aggregation. Which of the following address spaces are potential candidates from which the ISP can allot any one to the organization?

[GATE || 2020 MCQ || 2-mark]

I. 202.61.84.0/21
II. 202.61.104.0/21
III. 202.61.64.0/21
IV. 202.61.144.0/21

Consider a TCP connection between a client and a server with the following specifications: the round trip time is 6 ns, 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 acknowledgments are processed is __________. [GATE || 2020 NAT || 2-mark]

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? [GATE||2021||SET1||MSQ||2MARKS]