# Papers

B.E. (Computer Engineering) DESIGN AND ANALYSIS OF COMPUTER NETWORKS

(2008 Pattern) (Elective – I) (Sem. – I)

Time: 3 Hours]                                                                                              [Max. Marks :100

Instructions to the candidates:

1)            Answer any 3 questions from each section.

2)             Answers to the two sections should be written in separate books.

3)            Neat diagrams must be drawn wherever necessary.

4)             Figures to the right indicate full marks.

5)             Use of logarithmic tables slide rule, Mollier charts, electronic pocket calculator and steam tables is allowed.

6)            Assume suitable data, if necessary.

SECTION – I

Q1) a) What is arrival statistics and service statistics in M/M/1 system. Explain Markov chain formulation.                                                                                                      [10]

b) A athletic facility has five tennis courts. Players arrive at the court at a poisson rate of one pair per 10 min. and use a court for an exponentially distributed time with mean 40 min.                                                                                                                               [8]

i)            Suppose that a pair of players arrives and finds all courts busy and K other pairs waiting in queue. How long will they have to wait to get a court on the average?

ii)          What is the average waiting time in queue for players who find all courts busy on arrival?

OR

Q2) a) Person arrive at a xerox machine according to a poisson process with rate one per minute. The number of copies to be made by each person in uniformly distributed between 1 to 10. Each copy requires 3 sec. Find the average waiting time in queue when :  [10]

i)            Each person uses the machine on first come first serve basis.

ii)          Persons with no more than 2 copies to make are given preemptive priority over other persons.

b) Explain Jackson’s Theorem for closed Networks.                                            [8]

Q3) a) List and explain common resources. Used in system design with their metrics.      [8]

b) What is switch fabrics? Why does a third generation switch fabrics provides more band width than second generation switch.                                                   [8]

OR

Q4) a) Explain modeling and simulation techniques of system design with suitable example.     [8]

b) Explain physical and logical designing issues of Network Backbone.

[8]

Q5) a) Explain the rate-controlled scheduling for guaranteed-service connection. [8]

b) Explain, why do we prefer WFQ to WRR even in networks with fixed size packets.                                                                                                                     [8]

OR

Q6) a) Explain in details ATM forum end-to-end rate controlled scheme and credit based schemes of closed loop flow control.                                                           [8]

b)            If a token is 200 bytes long, the token bucket is 1 kbyte, and token arrive at the rate of 1 every second, what is the least and most delay suffered by a packet of size 800 bytes if it arrives when the token bucket has 100 bytes in it.                                        [8]

SECTION – II

Q7) a) Explain leaky-bucket regulator with help of diagram.                     [6]

b)            Enlist and explain important properties of traffic descriptor.           [6]

c)            Explain different techniques used for capacity planning of network. [6]

OR

Q8) a) What is peak-load pricing. Explain if peak-rate allocation is reasonable for data traffic.  [10]

b)            What is QoS? Explain different approaches to improve QoS. [8]

Explain router architecture with suitable diagram.                                      [8]

Explain expanded tries scheme in details.                                                     [8]

OR

What is IP trace back? What are IP trace-back evaluation schemes? Explain its implications and challenges.                                                                                                           [8]

Enlist and explain various packet scheduling algorithms.                          [8]

Divide a network 192. 168.4.0/24 into two sub networks having host size of 50. Find subnetwork address, subnet mask and IP address range for the sub network?             [8]

Explain which points are considered while planning and implementing network. [8]

OR

What is subnetting? You have been allocated a 130.16.0.0 IP address for your network. You have to subnet this into 13 subnets and allow for the expansion in the near future. Devise an IP subnet plan, giving the network, first host, last host and broadcast IP addresses for each subnet. Also specify the subnet mask you would use.                                                                             [8]

Discuss tools available for bandwidth and security management. [8]