2007 Anna University Chennai B.E Computer Science CS339 - COMPUTER NETWORKS Question paper

CS339 - COMPUTER NETWORKS

Time: Three Hours Maximum: 100 Marks
Answer All The Questions

PART – A (10 x 2 = 20 Marks)

1. Why network software is organized as a series of layer?

2. What are the two kinds of light sources used in fiber cables?

3. Reliability of CRC is better than that of simple parity and LRC. Justify this statement.

4. What is meant by bit stuffing?

5. Write short notes on virtual circuit organization of the subnet.

6. Differentiate between adaptive and non-adaptive routing algorithms.

7. What is meant by upward and downward multiplexing.

8. Mention some applications where UDP is preferred over TCP?

9. Mention the layer in which email gateway function. Also mention some of its applications

10. Define encryption

PART – B (5 x 16 = 80 Marks)

11.i) Compare OSI and TCP / IP reference models on form of their merits and demerits. (10)

ii) Differentiate between broadcast networks and point to point networks. (6)

12.a)i) Explain the CSMA/CD protocol with binary exponential back off algorithm used internet. (10)

ii) Assume that a network can cover a distance of 5000 meters and the RTT is 100 µ sec of the network operates at a speed of 20Mbps. What should be the minimum frame size to employ CSMA / CD? (6)

(OR)

12.b)i) Explain the sliding window protocol and compare its performance against the simple stop and wait protocol. (10)

ii) Given message is M(X) = X5 + X4+ X + 1 and the generator is G(X) = X4+X3+1 Compute CRC. (6)

13.a)i) Explain the distance vector routing algorithm. (8)

ii) Find the shortest path from node A to node D in the following network using the Bell mark kord routing algorithm. (8)
(OR)
13.b)i) Given three IP addresses are 32.46.7.3, 200.132.110.35 and 140.75.8.92. Find their classes, network addresses, broadcast address and their subnet marks. (6)
ii) Explain the token breket algorithm and compare its performance against the leaky bueket algorithm 14.a)i) Explain the Bres-way handshak protocol used to establish the connection in the transport layer. Also explain the protocol used to release the connection. (8)
ii) Explain the transport service access point and the various schemers used by the transport layer to find the TSAP at a server. (8)
(OR)
14.b)i) Explain the various fields of TCP header. (8)
ii) Write short notes about the pseudo header included in the TCP checkroom. (4)
iii) Draw the UDP header and explain its fields (4)
15.a) Explain the DNS in terms of name space, resource record and name server. (16)
(OR)
15.b) Explain the architecture of WWW as on client / server application (16

2007 Anna University Chennai B.E Computer Science Cryptography and Network Security Question paper

2007 SKR ENGINEERING COLLEGE B.E Computer Science Cryptography and Network Security University Question paper

IT1352- Cryptography and Network Security


PART-A 2*10=20

1.What is cryptography?
2.Give any four names of substitution techniques
3.What are the services defined by x.800?
4.What is the purpose of Diffie-Hellman algorithm?
5.Define man in the middle attack
6.List design objectives for HMAC
7.What is MAC?
8.What are the requirements for digital signature?
9.Give the Kerberos simple dialogue
10.What is firewall?

PART-B 5*16=80

11 a(i) Briefly explain about OSI security architecture (8 )
(ii) Explain briefly about data encryption standard (8 )

(OR)

b(i) Explain briefly about block cipher principles and modes of operation (12)
(ii) Explain about traffic confidentiality (4)

12 a(i) Explain briefly about Diffie-Hellman key exchange (16)

(OR)

b(i) Explain briefly about public key cryptography (8 )
(ii) What is the use of RSA algorithm? (8 )

13 a(i) Expalin briefly about MD5 message digest algorithm (12)
(ii) What is the use of authentication protocols? (4)

(OR)

b(i) Explain briefly about RIPEMD (16)

14 a(i) Explain about Kerberos (16)

(OR)
b(i) Explain briefly about web security (16)

15 a(i) Discuss the design principles of firewall (8 )
(ii) What is meant by password management? (8 )

(OR)

b(i) What is meant by virus and explain briefly about threats? (16)

2006 Anna University Chennai B.E Computer Science Computer Networks Question paper

CS-1302-Computer Networks
Nov/Dec 2006
Fifth Semester
Part A
1.State the purpose of layering in networks.
2.At what level of OSI model does repeaters, bridges, routers and gateways operate?
3.State the difference between token ring and FDDI.
4.Give the structure of encoder and decoder in error correction.
5.What is meant by IP spoofing? How can be router be used to prevent IP spoofing?
6.What kind of routing information do routers exchange among themselves while running distance vector algorithm? In particular, briefly describe the format of the routing information that is exchanged.
7.Briefly describe two advantages of using packet switching for data transmission.
8.Explain how TCP flow control works.
9.Why id DNS necessary? State its significance.
10.What is Security Parameter Index?

Part B
11.a.i).List four properties by which transmission media can differ.
ii).Three packet-switching networks each contain n nodes. The network has a star topology with a central switch, a ring respectively and a third is fully interconnected with a wire form every node to every other node. What are the best, average and worst case transmission paths in hops?

(Or)

11.b.i).Describe the key elements of protocols and the standards.
ii).Explain in detail the data transmission in OSI reference model.

12.a.i).How does the 802.11 media access control protocol ensure that the receiver has a greater chance to transmit the acknowledgement frame before any other wireless stations grab the media? Does it always guarantee that the acknowledgement frame sent by the receiver will not collide with another frame transmitted by another wireless station?
ii).Describe the collision avoidance mechanism used in 802.11 wireless LAN. In particular, how such a mechanism solves the hidden terminal problem.

(Or)

12.b.i).Describe two approaches by which packet loss is detected in a Go back-N ARQ protocol and selective.

13.a.i).How is the looping problem solved by switches and by routers? How do switches/routers handle link failure?
ii).Explain the IP addressing?

(Or)

13.b.i).In the virtual circuit network service model, before a virtual circuit is set up, the source router needs to specify a path from the source to the destination. What additional information do we need to maintain in the routing table to support this function? Write down the resulting routing table.

14.a.If UDP does not provide any service guarantees or reliable transfer, why cant application directly access IP and do without it? Explain UDP in details.

(Or)

14.b).What is QoS in networking? State the technique to improve Qos?

15.a).What are the following acronym SMTP, FTP, WWW and HTTP stand for? Explain their uses and state the strengths and weakness of each of them.

(Or)

15.b.i).Explain the role of a DNS on a computer network, including its involvement in the process of a user accessing a web page.
ii).Describe about symmetric-key Cryptography.

2008 Anna University Chennai B.E Computer Science CS 1302 - COMPUTER NETWORKS Question paper

B.E./B.Tech. DEGREE EXAMINATION, NOVEMBER/DECEMBER 2008.
Fifth Semester
(Regulation 2004)
Computer Science and Engineering
CS 1302 - COMPUTER NETWORKS
(Common to Information Technology)
(Common to B.E. (Part-Time) Fourth Semester Regulation 2005)
Time: Three hours Maximum: 100 marks

Answer ALL questions.
PART A - (10 x 2 = 20 marks)

1. For n devices in a network, what is the number of cable links required for a mesh, ring, bus and star topology?
2. What does the Shannon capacity have to do with communications?
3. How does a single-bit error differ from a burst error?
4. Compare a piconet and a scatter net.
5. What are the differences between classful addressing and classless addressing in IPV4?
6. Is the size of the ARP packet fixed? Explain.
7. Do port addresses need to be unique? Why of why not?
8. How are congestion control and quality of service related?
9. What are the two main categories of DNS messages?
10. How is HTTP similar to SMTP?

PART B - (5 x 16 = 80 marks)

11.(a) Discuss briefly about the layers present in the OSI model. [MARKS 16]
OR
(b) (i) Discuss briefly about the line coding process used for converting digital data to digital signals.
[MARKS 10]
(ii) Write a short note on transmission media. [MARKS 6]
12.(a) (i) With an example, illustrate how CRC encoder and decoder will work. [MARKS 10]
(ii) Compare and contrast the Go-Back-N ARQ protocol with selective repeat ARQ. [MARKS 6]
OR
(b) (i) Discuss in detail about the wireless LAN MAC sub layers. [MARKS 8]
(ii) Discuss briefly about the high speed networks. [MARKS 8]
13.(a) Discuss in detail about the OSPF routing protocol. [MARKS 16]
OR
(b) (i) Discuss briefly about the network address translation. [MARKS 10]
(ii) Define fragmentation and explain why the IPV4 and IPV6 protocol need to fragment some packets. [MARKS 6]
14. (a) How the connection is established using three-way handshaking, explain in detail? [MARKS 16]
OR
(b) (i) Discuss briefly about the techniques used to improve QoS. [MARKS 8]
(ii) Discuss about the Intserv, a flow-based QoS model. [MARKS 8]
15. (a) (i) Discuss briefly about the DNS in the internet. [MARKS 8]
(ii) Discuss briefly about the file transfer protocol. [MARKS 8]
OR
(b) (i) Discuss about the components of network management on the Internet. [MARKS 8]
(ii) Write short notes on symmetric-key cryptography. [MARKS 8]

2006 Anna University B.E COMPUTER SCIENCE COMPUTER NETWORKS Question paper

MODEL QUESTION PAPER

VI SEMESTER

B.E. COMPUTER SCIENCE AND ENGINEERING

CS339 - COMPUTER NETWORKS

Time: Three Hours Maximum: 100 Marks

Answer All The Questions

PART – A (10 x 2 = 20 Marks)

1. Why network software is organized as a series of layer?

2. What are the two kinds of light sources used in fiber cables?

3. Reliability of CRC is better than that of simple parity and LRC. Justify this statement.

4. What is meant by bit stuffing?

5. Write short notes on virtual circuit organization of the subnet.

6. Differentiate between adaptive and non-adaptive routing algorithms.

7. What is meant by upward and downward multiplexing.

8. Mention some applications where UDP is preferred over TCP?

9. Mention the layer in which email gateway function. Also mention some of its applications

10. Define encryption

PART – B (5 x 16 = 80 Marks)

11.i) Compare OSI and TCP / IP reference models on form of their merits and demerits. (10)

ii) Differentiate between broadcast networks and point to point networks. (6)

12.a)i) Explain the CSMA/CD protocol with binary exponential back off algorithm used internet. (10)

ii) Assume that a network can cover a distance of 5000 meters and the RTT is 100 µ sec of the network operates at a speed of 20Mbps. What should be the minimum frame size to employ CSMA / CD? (6)

(OR)

12.b)i) Explain the sliding window protocol and compare its performance against the simple stop and wait protocol. (10)

ii) Given message is M(X) = X5 + X4+ X + 1 and the generator is G(X) = X4+X3+1 Compute CRC. (6)

13.a)i) Explain the distance vector routing algorithm. (8 )

ii) Find the shortest path from node A to node D in the following network using the Bell mark kord routing algorithm. (8)

(OR)

13.b)i) Given three IP addresses are 32.46.7.3, 200.132.110.35 and 140.75.8.92. Find their classes, network addresses, broadcast address and their subnet marks. (6)

ii) Explain the token breket algorithm and compare its performance against the leaky bueket algorithm (10)

14.a)i) Explain the Bres-way handshak protocol used to establish the connection in the transport layer. Also explain the protocol used to release the connection. (8)

ii) Explain the transport service access point and the various schemers used by the transport layer to find the TSAP at a server. (8 )

(OR)

14.b)i) Explain the various fields of TCP header. (8 )

ii) Write short notes about the pseudo header included in the TCP checkroom. (4)

iii) Draw the UDP header and explain its fields (4)

15.a) Explain the DNS in terms of name space, resource record and name server. (16)

(OR)

15.b) Explain the architecture of WWW as on client / server application (16)

Career Opportunities for Network Administrators

Network administrator is one of the most sought after jobs in information technology. So, in case you are dreaming to be a network administrator, this could well be the perfect time as the Bureau of Labor Statistics estimates that the career openings in network administration will jump by 18 percent by 2016. The job functions of a network administrator could be challenging as he has to manage the various critical online functions, local area networks and wide area networks for government agencies and business organizations.

To be a network administrator, a bachelor's degree in computer science, is the most popular basic qualification, though there are other degree options like a bachelor's degree in math or engineering. An internship program might be useful in getting some work experience and a distinct advantage while applying for a net work administrator job.

Apart from the many online job boards for technical jobs like network administrators there is lot of part time and freelance positions as well. Experience and merit will have a major role in ensuring a bright future in this field as in any other career choice. So, make sure that you make yourselves updated with the latest developments in this field. The more experience certificates you have greater will be your demand.

The job functions of a network administrator is to create and manage networks and the various certification programs in networking will help you stay tuned with the latest innovations in this segment. There are many sought after certification programs like the Cisco network administrator certification, which on successful completion will make you a qualified network administrator.

Search online to find the listing of some of the best network administration institutes in the US. In case you have a technical inclination and an urge to succeed, network administrator job could well be your cup of tea.

The right career choice would take you closer to achieving your objective of a good job in life and that makes it something that should be done with care. However, most students tend to make their career choices for granted, which could have disastrous consequences later on. Always, keep an eye on the most up to date educational updates and news to make sure that you never run out of your professional excellence.

How to Protect Your Personal Data on A Wi-Fi Network

With the latest innovations and introductions to technology, people are increasingly benefitting and want to get the most out of them. In fact, a Wi-Fi network has been the latest demand for every laptop and smart phone user. The ultimate benefit we get from the Wi-Fi network is that we can get the fastest browsing and usage of internet applications. But this advantage involves some kinds of risks which affect the cyber security of your computer or online world.

Today's Wi-Fi networking products are sometimes unable to help the user get relief from online hacking and virus attacks. With wireless network security services you can save your time and get an effective solution for the safety of your computer and can make more efficient use of internet applications.

Internet security is the basic necessity of any server and helps in detecting unauthenticated elements that try to penetrate your accounts, emails or online world. Important tips essential for every Wi-Fi user wanting to improve network security on a wireless connection are mentioned below:

Change the default administrator username and password

Every home Wi-Fi network has an access point or router which controls the setting. Manufacturers provide some web pages that allow the owners to enter into the user's network, address and account information. These web tools can be protected by the login screen to allow only the rightful owner to work with it. By changing its settings, you can easily prohibit hackers from misusing your control panel to extract information.

Get WPA/WEP encryption

Encryption is a technology that scrambles the messages sent over wireless networks and makes them temporarily unreadable. Pick the strongest form of encryption that is compatible with your wireless network. Since all Wi-Fi devices on your network must share identical encryption, you need to find the "lowest common denominator" setting.

Avoid auto connect to open Wi-Fi networks

When you connect to an open Wi-Fi network, your computer is exposed to security risks. Although most computers have an available setting that allows these connections to be processed automatically without bothering the user, the user should disable this setting to prevent unauthorized connection to his network.

Use firewalls for every computer and router

The latest network routers have built-in firewall capabilities with the option of disabling them. These firewalls are very essential for wireless network security since the firewalls installed can provide you with regular alerts and notifications in case of any unidentified software heading your way. It also scans incoming and outgoing emails to check for viruses, spam and hacking attempts. Therefore, for extra protection, consider installing and running personal firewall software on each computer connected to the router.

By following these important tips, you can prevent your computer and router from being hijacked by hackers. With the benefits of the best network security tools, you can prevent unauthorized persons from getting into your Wi-Fi traffic. Search online to find the best network security tool for the ultimate wireless network security.

Internet Connection and Wireless Networking Technology

An internet connection is essential in a computer system. It enables one to search for information, communicate with friends and family, and share personal files and documents to other users. It also provides entertainment through online games and social networking sites. Because of the continuous expansion of internet use, Information Technology (IT) specialists continue to create innovative ways to provide internet access to every computer owner.

A computer unit is connected to the internet by an Internet Service Provider (ISP). The ISP gives an ISP number which serves as a gateway to the internet. ISP numbers vary for every computer unit connected to the internet. Usually, ISPs require monthly fees in maintaining internet connection.

ISPs provide three types of internet connection: dial-up, broadband, and WLAN. The dial-up connection is the oldest service system of ISPs. This utilizes a dial-up modem that is connected to a standard telephone line. Older computer models come with a pre-installed dial-up modem. To establish a dial-up connection, one must dial the ISP number in the telephone line to be able to connect to the internet. Dial-up connection is the cheapest and slowest service system offered by ISPs.

Broadband connections utilize Digital Subscriber Lines (DSL) and cable modems which connect a computer system to the internet. It is a kind of high-speed internet connection which enables you to browse webpages and download files faster than a dial-up connection. DSLs and cable modems give you access to the internet at all times. However, a new kind of connection is now provided by ISPs with the invention of wireless networking boston, Massachusetts provides IT solutions for connection problems).

In wireless networking boston ISPs generate internet connection using radio waves and microwaves. Wireless local area networking (WLAN) cards and wireless routers are used in linking computer systems for file sharing, as well as in connecting computers to the internet. WLAN is typically known as "Wi-Fi". Recently, public transportations and establishments have started offering Wi-Fi internet connection for various portable devices like PDAs and laptops.

In the invention of wireless networking boston network and information technology landscape will continue to evolve. IT specialists continue to find innovative ways on how to connect computer systems anytime, anywhere in the world.