List of top Computer Networks Questions asked in GATE CS

Consider the following two statements.
\[ S_1 : \text{Destination MAC address of an ARP reply is a broadcast address.} \] \[ S_2 : \text{Destination MAC address of an ARP request is a broadcast address.} \] Which one of the following choices is correct?
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?
Consider two hosts \(P\) and \(Q\) connected through a router \(R\). The maximum transfer unit (MTU) 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. Which of the following statements is/are correct?

Consider the sliding window flow-control protocol operating between a sender and a receiver over a full-duplex error-free link. Assume the following:

  • The time taken for processing the data frame by the receiver is negligible.
  • The time taken for processing the acknowledgement frame by the sender is negligible.
  • The sender has infinite number of frames available for transmission.
  • The size of the data frame is 2,000 bits and the size of the acknowledgement frame is 10 bits.
  • The link data rate in each direction is 1 Mbps (= 106 bits per second).
  • One way propagation delay of the link is 100 milliseconds.

The minimum value of the sender’s window size in terms of the number of frames (rounded to the nearest integer) needed to achieve a link utilization of 50% is  .

Consider an ethernet segment whose transmission is \(10^8\) bits per second. Maximum segment length \(500\ m\), speed of the provocation media velocity is \(2 × 10^8\) meter per second. What is the minimum frame size in bits ?
Which one of the following CIDR profix exactly represent the range of IP addresses 10.12.2.0 to 10.12.3.255?
Which of the following fields of IP header is/are always modified by any router before it forwards to IP Packet ?