GATE PYQ

Computer Network

Q231.
Which of the following functionalities must be implemented by a transport protocol over and above the network protocol ?

Q232.
Suppose that the maximum transmit window size for a TCP connection is 12000 bytes. Each packet consists of 2000 bytes. At some point in time, the connection is in slow-start phase with a current transmit window of 4000 bytes. Subsequently, the transmitter receives two acknowledgments. Assume that no packets are lost and there are no time-outs. What is the maximum possible value of the current transmit window?

Q233.
Host A sends a UDP datagram containing 8880 bytes of user data to host B over an Ethernet LAN. Ethernet frames may carry data up to 1500 bytes (i.e. MTU=1500 bytes). Size of UDP header is 8 bytes and size of IP header is 20 bytes. There is no option field in IP header. How many total number of IP fragments will be transmitted and what will be the contents of offset field in the last fragment?

Q234.
Consider the following statements. I. TCP connections are full duplex II. TCP has no option for selective acknowledgement III. TCP connections are message streams

Q235.
Assume that the bandwidth for a TCP connection is 1048560 bits/sec. Let \alpha be the value of RTT in milliseconds (rounded off to the nearest integer) after which the TCP window scale option is needed. Let \beta be the maximum possible window size with window scale option. Then the values of \alpha and \beta are

Q236.
The transport layer protocols used for real time multimedia, file transfer, DNS and email, respectively are

Q237.
A program on machine X attempts to open a UDP connection to port 5376 on a machine Y, and a TCP connection to port 8632 on machine Z. However, there are no applications listening at the corresponding ports on Y and Z. An ICMP Port Unreachable error will be generated by

Q238.
Which one of the following uses UDP as the transport protocol?

Q239.
Consider an instance of TCP's Additive Increase Multiplicative Decrease (AIMD) algorithm where the window size at the start of the slow start phase is 2 MSS and the threshold at the start of the first transmission is 8 MSS. Assume that a timeout occurs during the fifth transmission. Find the congestion window size at the end of the tenth transmission.

Q240.
Which one of the following socket API functions converts an unconnected active TCP socket into a passive socket?