Computer Networks-Sem5-Sept-2019

Name   …………………………… Roll No ……………………….

SAINTGITS COLLEGE OF APPLIED SCIENCES

INTERNAL ASSESSMENT EXAMINATION, SEPTEMBER2019

Department of BCA, Semester 5

COMPUTER NETWORKS

Total   : 80 marks                                                                        Time:3Hours

Section A

Answer any 10 questions. Each question carries 2 marks.

1.what is Cryptography?

                                Cryptography involves creating written or generated codes that allow information to be kept secret. ... Information security uses cryptography on several levels. The information cannot be read without a key to decrypt it. Symmetric and Asymmetric key cryptography.

2.What is datagram?

                     A datagram is a basic transfer unit associated with a packet switched network. Datagram are typically structured in header and payload sections. Datagram provide a connectionless-communication service across a packet-switched network. The delivery, arrival time, and order of arrival of datagram need not be guaranteed by the network.

3.What is peak amplitude?

The peak amplitude of a signal is the absolute value of its highest intensity, proportional to the energy it carries.

4.What is Bluetooth?

        Bluetooth is a wireless LAN  technology designed to connect devices of different functions such as telephones, notebooks, computers, cameras, and so on. A Bluetooth network is an ad-hoc network, which means that the network is formed spontaneously.

5.What is Roaming?

       Roaming is a wireless telecommunication term typically used with mobile devices (like mobile phones). It refers to the mobile phone being used outside the range of its home network and connects to another available cell network.

6. What is DNS?

·         Domain Name System(.5)

·         Domain name space-label ,fully and partially qualified domain name eg(1.5)

7. What is FTP ?

·         File Transfer protocol.(.5)

·         Popular protocol involved in transferring files(.5)

·         Control connection and data connection(1)

8.What is Hard Hands-off?

A hard handoff is a handoff technique used with cellular networks that requires the user's connection to be entirely broken with an existing base station   before being switched to another base station.

9. What is public and private key?

·         A private key is a tiny bit of code that is paired with a public key to set off algorithms for text encryption and decryption. It is created as part of public key cryptography during asymmetric-key encryption and used to decrypt and transform a message to a readable format. .. A private key is also known as a secret key.

·         Public key is announced to public. it is used in asymmetric key cryptography.

10.What is unicast addressing?

unicast refers to a one-to-one transmission from one point in the network to another point; that is, one sender and one receiver, each identified by a network address.

11. What is bitrate and baudrate?

      The bit rate is the number of bits transmitted per second, whereas, the baud rate is the number of signal units transmitted per second and one signal unit is able to represent one or more bits. Therefore, baud rate is always less than or equal to the bit rate but never greater.

12.What is NAT?                    (10x2=20)

NAT  enables private IP networks that use unregistered IP addresses to connect to the Internet

                     Section B

Answer any six of the following. Each question carries 5 marks.

13.Explain twisted pair cable?

Twisted pair is the ordinary copper wire that connects home and many business computers to the telephone company. To reduce crosstalk or electromagnetic induction between pairs of wires, two insulated copper wires are twisted around each other. Each connection on twisted pair requires both wires.

14. Explain transmission impairments.

·         Attenuation ,distortion and noise  Definition with figure(1.5+1.5+2)

15.Explain ALOHA Protocol?

16. Explain Variable size framing

·         Definition-framing(1)

·         Character –oriented(2)

·         Bit-oriented(2)

17.Explain Multiplexing?

18. Explain different topologies

·         Definition-topology(1)

·         Ring, mesh, star ,bus, topologies with figures(4)

19.Explain unguided media?

An unguided transmission transmits the electromagnetic waves without using any physical medium. 

20.Explain TCP/IP  protocol Suit.

·         Figure with  four layers(2.5)

·         Explanation of Protocols in each layer(2.5)

21.Explain IPV4?

Internet Protocol version 4 (IPv4) is the fourth version of the Internet Protocol (IP). It is one of the core protocols of standards-based internetworking methods in the Internet and other packet-switched networks. IPv4 was the first version deployed for production in the ARPANET in 1983.

                                                                (6x5=30)

         

Section C.

Answer any two of the following.

Each question carries 15 marks

22.Explain various layers of ISO OSI reference model.

·         Different Layers-physical,datalink,network,transport,session,presentation,application (3)

·         Functions of each layer   (9)

·         Figure (3)

23. Explain guided and unguided transmission media.

Guided − In guided media, transmitted data travels through cabling system that has a fixed path. For example, copper wires, fiber optic wires, etc. Unguided − In unguided media, transmitted data travels through free space in form of electromagnetic signal. For example, radio waves, lasers, etc.

24.Explain different multiple  access protocols

The multiple control access methods can be divided into sub-categories:

• Random access methods

The random access methods are:

• Aloha
• Pure Aloha
• CSMA/CD
• CSMA/CA

25.Explain simple parity check code and hamming code.

·         Block coding  and Linear block coding Definition with general figure  (5)

·         Simple parity check code with figure(5)

·         Hamming code(5)

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