Computer Communication and Network BSCS

Subject: CCN Max Marks: 50 Time: 2 hrs Exam: Final Class: BSCS(S)

Q.No.1 In the figure below, give the virtual circuit tables for all the switches after each of the

following connections is established. Assuming that the sequence of connections is cumulative;

that is, the first connection is still up when the second connection is established, and so on. Also

assume that the VCI assignment always picks the lowest unused VCI on each link, starting with

0.

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a) Host A connect to

Host B.

b) Host C connect to

Host G.

c) Host E connect to

Host I.

d) Host D connect to

Host B.

Provide switching table

for each switch

Q.No2: Suppose station s1 wants to communicate s4. There is not direct path exists between

these two nodes; data traffic must have to pass through s2 and s3 stations respectively. The

distance between s1 and s2 is 2000 Km (long distance) and the intermediate link is digital. The

link between s2 and s3 is analog and can communicate with each other by using digital to analog

conversion must be done at s2. The link between s3 and s4 is digital and distance is 250m, so

again conversion is required and link has high bandwidth but struggling with synchronization

issues. Moreover the users between s1 and s2 are 20 and bandwidth is 1Gb. We require 4 voice

channels. 4 data channels. The users between s2 and s3 are 500 but they only can listen the

proceedings but requires the proceedings in 4 different languages simultaneously. The users

between s3 and s4 are of three categories i.e. one with very low budget, second one requires

multiple frequencies with data rate of 500Mbps and last ones requires very high data rate around

1Gbps. Provide details for the followings

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1. Clearly state your assumptions (if any)

2. Design model (Diagram)

3. Suggest appropriate communication medium and justify.

4. Clearly mention which encoding/modulation scheme you will opt and why?

5. How Analog to digital conversation and vice versa will take place.

6. Process 100110 string according to your suggested scheme.

Q.No.3. A company has purchased a address 194.16.10.0, now intended to start an ISP, provides

internet and other services, assuming that initially 2-3 addresses per network would be sufficient.

You are requested to calculate max. no. of subnets, along with first and last subnets address and

mention addresses of first, last and broadcast addresses in those subnets.

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