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CMR INSTITUTE OF TECHNOLOGY QUESTION BANK

Department of Electronics and Communication Engineering Semester :VIII A & B Subject :DIGITAL SWITCHING SYSTEM

Course Instructor: Mrs.P.Meena, Subject code : 10EC82

Unit 1 Q1) Q2) Q3) Q4)

Explain in brief regulation, standard in a telecommunication networks. Explain in brief with a neat diagram different network configuration and structures Explain various types of network structure. Explain brief with neat diagram, nation telecommunication network.

Q5)

Explain in brief power level encountered in telecommunication transmission system.

Q6)

Design any one type of PDH with a suitable diagram.

Q7)

Explain frequency division multiplexing with respect to a suitable block diagram.

Q8)

Explain in brief the operation of a four wire circuit used in two way transmission system

Q9)

Explain in brief PCM primary multiplex group

Q10)

With a block schematic, explain the national telecommunication network.

Q11)

Differentiate between TDM and FDM transmission network with suitable diagram.

Q12)

With neat sketch, explain synchronous digital hierarchy (SDH) with frame structures

Q13)

With the help of neat circuit diagram explain the principle of Four wire circuits.

Q14)

Explain the working principle of FDM with the help of neat diagram.

Q15)

Explain the working principle of TDM with the help of neat diagram.

Q1)

Unit 2 EVOLUTION OF SWITCHING SYSTEMS Highlight the advantage and disadvantage of cross bar switching

Q2) Q3) Q4) Q5)

Describe Functions of switching system Explain Basic Central office linkage Explain neatly with diagram, the evolution of digital switching system. Explain in brief Evolution of digital switching from analog switching with neat diagrams.

Q6)

Explain Building blocks of a digital switching system.

Q7)

Explain Basic call processing of incoming and outgoing calls through DSS.

Q8)

Write short notes on stored program control switching systems with neat diagram.

Q9) Q10) Q11) Q12) Q13) Q14) Q15)

Differentiate between outside plant and inside plant. Explain in brief what you mean by message switching and circuit switching. Discuss the functions of switching system. What is DTMF? Explain the working of a push button dial system. What is sidetone coupling? What is its significance? Explain the working of anti sidetone circuit? What is meant by ‘non-blocking’ configuration or networks in the case of timedivision switching. Give the classification of switching system compare the same. Unit -3 TELECOMMUNICATIONS TRAFFIC

Q1)

Explain the following pure i) BHCA ii) congestion iii) unit of traffic iv) Occupancy v) Busy hour

Q2) Q3)

Draw and Explain distributed frames with the neat diagram Explain i) holding time ii)Delay system iii) markov chain

Q4)

Q5)

On an average one call arrives every 5 seconds during a period of 10 seconds , what is the probability that i)No call arriver ii one call arrives iii) 2 call arrives iv) more than 2 calls arrives where µ=2 Explain mathematical model

Q6) Q7)

Explain Erlangs lost call formula with related expressions. Explain the following pure i)chance traffic ii) congestion

Q8)

Derive probability of delay using second Erlangs distribution formula.

Q9) Q10)

Give the definition for i) Dimension problem ii) full availability iii) Traffic measurement. Explain with a neat diagram state transition diagram for N trunk.

Q11)

Write a short notes on grades of telecommunication service.

Q12)

An exchange is designed to handle 2000 calls during the busy hour. One day, the number of calls during the busy hour was 2200. Find the resulting grade of service. A subscribe makes 3 phone calls of 3 min, 4min and 2 min duration in a one hour period calculate subscriber traffic in Erlangs, CCS, CM and CS. A traffic of 2E is offered to a group of 4 trunks. Find the GOS and probability of a) On trunk free b)At least one trunk free c) At least one trunk busy d) All trunks free. With a poission arrival of two calls per minute, during a period of two minutes, what is the probability that 1) No call arrives? 2) One call arrives? 3) Two call arrives? 4) More than two calls arrive? Unit-4 SWITCHING SYSTEMS What is grading? Describe various types of gradings. A group of 21 trunks provides a GOS of service of 0.01 when offered 12E Of traffic. 1. How much is the GOS improved if one extra trunk is added to the group? 2. How much does the GOS deteriorate if one trunk is out of service? Explain and Derive three stage network with M Incoming and N Outgoing trunks Explain and Derive two stage network with N Incoming and N Outgoing trunks Explain GOS of link system. Design a fully interconnected 3-stage network with 200 incoming line and 200

Q13) Q14) Q15)

Q1) Q2)

Q3) Q4) Q5) Q6)

Q7) Q8) Q9) Q10) Q11) Q12) Q13) Q14) Q15)

Q1) Q2) Q3) Q4)

Q1) Q2) Q3) Q4) Q5)

Q1) Q2) Q3) Q4) Q5) Q6) Q7) Q8) Q9)

Q1) Q2) Q3) Q4)

outgoing line with the minimum number of Explain Distributed system Derive an expression for second Erlang distribution Explain briefly the meaning of following terms i) grade groups ii) Availability Explain the terms i) busy hour ii) congestion iii) unit of traffic Design a fully interconnected 3-stage network with 100 incoming line and 100 outgoing line with the minimum number of Explain Distributed system Find the best grading for a 6 group grading with availability 20 and when the number of trunks 35. Design a grading system for connecting 20 trunks to switches having 100 outlets. Find the best solution among the options. A grading is required to connect 30 outgoing trunks to switches of availability 10 i) Design a progressive grading ii) Homogeneous grading. Explain the term i) skipped grading ii)homogeneous grading. Design a 3-stage network with 100 incoming line and 400 outgoing line . specify assumptions and draw the 3 stage network. Unit- 5 TIME DIVISION SWITCHING Explain space switch & time space time. Explain frame synchronization Discuss the need for frame alignment in time division switching networks. Explain double ended unilateral and bilateral synchronization systems. With a neat sketch, explain a space switch for K incoming PCM highways and m outgoing PCM highways. Unit-6 SWITCHING SYSTEM SOFTWARE Explain Basic central office linkage. Explain the basic call processing of digital switching system Explain the working of operating system indicating the basic software architecture of a typical digital switching system. Explain Basic central office linkage. Explain Feature Flow Diagrams Unit-7 MAINTENANCE OF DIGITAL SWITCHING SYSTEM Explain the interfaces of digital switching central office. Explain Impact of software patches on digital switching system maintainability Explain Growth of digital switching system central office Explain system outage and its impact on digital switching system reliability. Highlight the strategy for improving software quality. Write a short note on defect analysis. Explain generic switch software architecture. Explain in brief a methodology for proper maintenance of a DSS, such as diagnostic capabilities and firmware deployment. Explain the organizational interfaces of a typical DSS central office. Unit-8 A GENERIC DIGITAL SWITCHING SYSTEM MODEL Explain in brief common characteristic of digital switching system. Explain three level scheme of recovery strategy in digital switch. Write short notes on reliability analysis or network control processor. Explain in brief generic switch hardware architecture.

Q5) Q6) Q7)

Write short notes on i) Reliability analysis or Network Control Processors ii) Recovery Strategy. List the basic steps necessary to complete a simple call. Discuss the analysis report for DSS.