Misc Topics in Computer Networks

Question 1

Which one of the following is not a client server application?

• Internet chat
• Web browsing
• E-mail
• ping

Question 2

Match the following:

(P) SMTP     (1) Application layer
(Q) BGP      (2) Transport layer
(R) TCP      (3) Data link layer
(S) PPP      (4) Network layer
             (5) Physical layer 

• P – 2 Q – 1 R – 3 S – 5
• P – 1 Q – 4 R – 2 S – 3
• P – 1 Q – 4 R – 2 S – 5
• P – 2 Q – 4 R – 1 S – 3

Question 3

In the following pairs of OSI protocol layer/sub-layer and its functionality, the INCORRECT pair is

• Network layer and Routing

• Data Link Layer and Bit synchronization

• Transport layer and End-to-end process communication

• Medium Access Control sub-layer and Channel sharing

Question 4

Choose the best matching between Group 1 and Group 2.

   Group-1   	  	  Group-2   
 P. Data link          1. Ensures reliable transport of data
                           over a physical point-to-point link
 Q. Network layer      2. Encoder/decodes data for physical
                          transmission
 R. Transport layer    3. Allows end-to-end communication
                          between two processes
                       4. Routes data from one network
                          node to the next

• P-1, Q-4, R-3
• P-2, Q-4, R-1
• P-2, Q-3, R-1
• P-1, Q-3, R-2

Question 5

Which of the following is NOT true with respect to a transparent bridge and a router?

• Both bridge and router selectively forward data packets
• A bridge uses IP addresses while a router uses MAC addresses
• A bridge builds up its routing table by inspect­ing incoming packets
• A router can connect between a LAN and a WAN

Question 6

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 may total number of IP fragments will be transmitted and what will be the contents of offset field in the last fragment?

• 6 and 925
• 6 and 7400
• 7 and 1110
• 7 and 8880

Question 7

Since it is a network that uses switch, every packet goes through two links, one from source to switch and other from switch to destination. Since there are 10000 bits and packet size is 5000, two packets are sent. Transmission time for each packet is 5000 / 10⁷ microseconds. Two hosts are connected via a packet switch with 10⁷ bits per second links. Each link has a propagation delay of 20 microseconds. The switch begins forwarding a packet 35 microseconds after it receives the same. If 10000 bits of data are to be transmitted between the two hosts using a packet size of 5000 bits, the time elapsed between the transmission of the first bit of data and the reception of the last bit of the data in microseconds is _________.

• 1075
• 1575
• 2220
• 2200

Question 8

Which one of the following statements is FALSE?

• TCP guarantees a minimum communication rate
• TCP ensures in-order delivery
• TCP reacts to congestion by reducing sender window size
• TCP employs retransmission to compensate for packet loss

Question 9

Which one of the following statements is FALSE?

• HTTP runs over TCP
• HTTP describes the structure of web pages
• HTTP allows information to be stored in a URL
• HTTP can be used to test the validity of a hypertext link

Question 10

A serial transmission Ti uses 8 information bits, 2 start bits, 1 stop bit and 1 parity bit for each character. A synchronous transmission T2 uses 3 eight bit sync characters followed by 30 eight bit information characters. If the bit rate is 1200 bits/second in both cases, what are the transfer rates of Ti and T2?

• 100 characters/sec, 153 characters/sec

• 80 characters/sec, 136 characters/sec

• 100 characters/sec, 136 characters/sec

• 80 characters/sec, 153 characters/sec