CN |Gate-2008| Computer Networks
- What is the maximum size of data that the application layer can pass on to the TCP layer below? [GATE – 2008]
a. Any size
b. 216 bytes-size of TCP header
c. 216 bytes
d. 1500 bytes
Answer : a)
- Which of the following system calls results in the sending of SYN packets? [GATE – 2008]
a. socket
b. bind
c. listen
d. connect
Answer : d)
- In the slow start phase of the TCP congestion control algorithm, the size of the congestion window : [GATE – 2008]
a. does not increase
b. increases exponentially
c. increases quadratically
d. increases linearly
Answer : b)
- If a class B network on the Internet has a subnet mask of 255.255.248.0, what is the maximum number of hosts per subnet? [GATE – 2008]
a. 1022
b. 1023
c. 2046
d. 2047
Answer : c)
- A computer on a 10Mbps network is regulated by a token bucket. The token bucket is filled at a rate of 2Mbps. It is initially filled to capacity with 16Megabits. What is the maximum duration for which the computer can transmit at the full 10Mbps? [GATE – 2008]
a. 1.6 seconds
b. 2 seconds
c. 5 seconds
d. 8 seconds
Answer : b)
- A client process P needs to make a TCP connection to a server process S. Consider the following situation: the server process S executes a socket (), a bind () and a listen () system call in that order, following which it is preempted. Subsequently, the client process P executes a socket () system call followed by connect () system call to connect to the server process S. The server process has not executed any accept() system call. Which one of the following events could take place? [GATE – 2008]
a. connect ( ) system call returns successfully
b. connect ( ) system call blocks
c. connect ( ) system call returns an error
d. connect ( ) system call results in a core dump
Answer : c)
- Provider the best matching between the entries in the two columns given in the table below: [GATE – 2008]
| I. | Proxy Server | a. | Firewall |
| II. | Kazaa, DC++ | b. | Caching |
| III. | Slip | c. | P2P |
| IV. | DNS | d. | PPP |
a. I-a, II-c, III-d, IV-b
b. I-b, II-d, III-c, IV-a
c. I-a, II-d, III-c, IV-b
d. I-b, II-c, III-d, IV-a
Answer : a)
- A 1Mbps satellite link connects two ground stations. The altitude of the satellite is 36,504 km and speed of the signal is 3 × 108 m/s. What should be the packet size for a channel utilization of 25% for a satellite link using go-back-127 sliding window protocol? Assume that the acknowledgment packets are negligible in size and that there are no errors during communication. [GATE – 2008]
a. 120 bytes
b. 60 bytes
c. 240 bytes
d. 90 bytes
Answer : a)
- The minimum frame size required for a CSMA/CD based computer network running at 1 Gbps on a 200 m cable with a link speed of 2 × 108 m/s is : [GATE – 2008]
a. 125 bytes
b. 250 bytes
c. 500 bytes
d. None of these
Answer : b)
CN |Gate-2008|
- Two popular routing algorithms are Distance Vector(DV) and Link State (LS) routing. Which of the following are true? (S1) Count to infinity is a problem only with DV and not LS routing (S2) In LS, the shortest path algorithm is run only at one node (S3) In DV, the shortest path algorithm is run only at one node (S4) DV requires lesser number of network messages than LS : [GATE – 2008]
a. S1, S2 and S4 only
b. S1, S3 and S4 only
c. S2 and S3 only
d. S1 and S4 only
Answer : d)
- Which of the following statements are TRUE? (S1) TCP handles both congestion and flow control (S2) UDP handles congestion but not flow control (S3) Fast retransmit deals with congestion but not flow control (S4) Slow start mechanism deals with both congestion and flow control : [GATE – 2008]
a. S1, S2 and S3 only
b. S1 and S3 only
c. S3 and S4 only
d. S1, S3 and S4 only
Answer : b)
CN |Gate-2008|
- Host X has IP address 192.168.1.97 and is connected through two routers R1 and R2 to another host Y with IP address 192.168.1.80. Router R1 has IP addresses 192.168.1.135 and 192.168.1.110. R2 has IP addresses 192.168.1.67 and 192.168.1.155. The netmask used in the network is 255.255.255.224. Given the information above, how many distinct subnets are guaranteed to already exist in the network? [GATE – 2008]
a. 1
b. 2
c. 3
d. 6
Answer : c)
CN |Gate-2008|
- Host X has IP address 192.168.1.97 and is connected through two routers R1 and R2 to another host Y with IP address 192.168.1.80. Router R1 has IP addresses 192.168.1.135 and 192.168.1.110. R2 has IP addresses 192.168.1.67 and 192.168.1.155. The netmask used in the network is 255.255.255.224. Which IP address should X configure its gateway as? [GATE – 2008]
a. 192.168.1.67
b. 192.168.1.110
c. 192.168.1.135
d. 192.168.1.155
Answer : b)
- The three way handshake for TCP connection establishment is shown below.
Which of the following statements are TRUE? (S1) Loss of SYN + ACK from the server will not establish a connection (S2) Loss of ACK from the client cannot establish the connection (S3) The server moves LISTEN → SYN_RCVD → SYN_SENT → ESTABLISHED in the state machine on no packet loss (S4) The server moves LISTEN → SYN_RCVD → ESTABLISHED in the state machine on no packet loss. [GATE – 2008]
a. S1 and S4
b. S1 and S3
c. S2 and S4
d. S2 and S3 only
Answer : a)