PART-B (16 MARKS) CS2302 Computer Networks

PART-B (16 MARKS)

UNIT I

1. Explain the OSI-ISO model I of computer with neat diagram. (16)

2. Distinguish between Point to Point links and multi-point links with relevant diagram. (16)

3. (i) compare connection oriented and connection less service. (8)

   (ii)What are the major component of an optical communication system discuss. (8)

4. Write shot notes on

a. Network Hierarchy (4)

b. Ethernet (4)

c. Token ring (4)

d. Ring topology (4)

5. Perform a comparative study between the ISO-OSI model and TCP/IP reference

model. (16)

1. Write notes on Issues in the data link layer (8)
2. Write notes on  Hybrid multiple access techniques (10)

UNIT II

1. Write short notes on.

a. GO Back NARQ (8)

b. Selective Repeat ARQ (8)

2. (i) Explain Hamming code technique to correct single bit error with an example. (8)

    (ii) Explain numbering of frames in GO Back NARQ, Selective Repeat ARQ protocols. (8)

3. (i) Explain MAC Ethernet protocol. (8)

    (ii) Explain MAC sub layer protocol and frame structure of 802.16. (8)

4. Explain the following Inter connection devices also discuss their uses

a. Repeater (4)

b. Bridge (4)

c. Switch (4)

d. Gateway (4)

5. (i) Consider a 32- bit Block of data 11100111 11011101 00111001 10101001 that has been to be transmitted If longitudinal Redundancy check is used what is the transmitted bit stream? (8)

   (ii) In the Hamming code for a data unit of ‘m’ bits how do you know compute the number of redundant bits “r’ needed? (8)

6. (i) Explain any one of the protocols used for flow control in noisy channels. (8)

    (ii) Write short note on

a. sliding windows (4)

b. X-MODEM (4)

7.Explain about SONET (NOV/DEC 2007) 

  

UNIT III

1. Find the class of each IP address given suitable explanation. (16)

a. 227.12.14.87

b. 193.14.56.22

c. 14.23.120.8

d. 252.5.15.111

e. 134.11.78.56

f. 000 000 00 1111 0000 11111111 00110011

g. 10000000 1111 0000 11111111 00110011

2. Discuss how DES Algorithm works. (16)

3. State the major difference between Vector Routing and link state routing. (16)

4. Discuss how these routing and link state routing techniques work. (16)

5. What is the subnet work address if the destination address is 200.45.34.56 and the subnet mask is 255.255.240.0. (16)

6. What are the limitations of distance vector routing. How are they addressed in link state routing? (16)

7. Explain routing of mobile hosting. (16)

8. Write notes on BGP and CIDR (10)

UNIT IV

1. i. Discuss how multiplexing and demultiplexing is done in the transport layer. (8)

    ii. Explain in detail the mechanism in transport layer for controlling congestion. (8)

2. i) Explain choke packets methods of congestion control. (8)

    ii) Explain classless inter domain running(CINR). (8)

3. i) Explain various problem and corresponding solution in establishing a connection at transport layer. (8)

   ii) Explain the connection release process applied at transport layer. (4)

   iii) Explain window management in TCP. (4)

4. i) Discuss about quality of services. (8) (MAY/JUNE 2009)

    ii) Write short notes on integrated services. (8)

5.Explain the working of TCP using the state diagram(12)(MAY/JUNE 2009)

6.Discuss the operation of IntServ for providing QoS.(12)(MAY/JUNE 2009)

UNIT V

1.i) Explain in detail the title transfer protocol. (8)

   ii) Describe the architecture of ISDN. (8)

2. i) Explain in detail a protocol for electronic mail. (8)

    ii) Explain in detail any one ISDN protocol. (8)

3. i) what is HTTP protocol used for? (6)

    ii) What is the default port number of HTTP protocol? (5)

    iii) Discuss the features of HTTP and also discuss how HTTP works. (5)

4. Explain the importance of firewalls. (16)

5. Explain in detail the following

    i) Fault management. (8)

    ii) Security management. (8)

6. Write notes on Security protocols PGP & SSH (12)

7. Write notes on IMAP, POP3 (8)

8. Discuss the various commands used in FTP (12) (MAY/JUNE 2009)

9. Explain the salient features of the SMTP protocol (12) (MAY/JUNE 2009)

CS2302 Computer Network

15.  How does NRZ-L differ from NRZ-I?

In the NRZ-L sequence, positive and negative voltages have specific meanings: positive for 0 and negative for 1. in the NRZ-I sequence, the voltages are meaningless.

Instead, the receiver looks for changes from one level to another as its basis for recognition of 1s.

16. What are the responsibilities of data link layer?

Specific responsibilities of data link layer include the following. a) Framing b) Physical addressing c) Flow control d) Error control e) Access control.

17. What are the ways to address the framing problem?

·         Byte-Oriented Protocols(PPP)

·         Bit-Oriented Protocols(HDLC)

·         Clock-Based Framing(SONET)

18. Distinguish between peer-to-peer relationship and a primary-secondary relationship. peer -to- peer relationship?

            All the devices share the link equally.

Primary-secondary relationship: One device controls traffic and the others must transmit through it.

19. Mention the types of errors and define the terms?

            There are 2 types of errors

·         Single-bit error.

·         Burst-bit error.

Single bit error: The term single bit error means that only one bit of a given data unit (such as byte character/data unit or packet) is changed from 1 to 0 or from 0 to 1.

Burst error:  Means that 2 or more bits in the data unit have changed from 1 to 0 from 0 to 1.

20.  List out the available detection methods.

             There are 4 types of redundancy checks are used in data communication.

·         Vertical redundancy checks (VRC).

·         Longitudinal redundancy checks (LRC).

·         Cyclic redundancy checks (CRC).

·         Checksum.

21. Write short notes on VRC.        

The most common and least expensive mechanism for error detection is the vertical redundancy check (VRC) often called a parity check. In this technique a redundant bit called a parity bit, is appended to every data unit so, that the total number of 0’s in the unit (including the parity bit) becomes even.