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Textbook

《Telecommunication SwitchingSystems and Networks》

《现代电信交换与网络-英文版》

Author: Thiagarajan Viswanathan 出版：电子工业出版社，2009.1

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About the languages

Writing: English

Speaking: English + Chinese

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About the Grade

Final examination: 50%

Attendance and Homework: 50%

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About the contents

This class mainly focuses on theconcepts and principles of differentswitching techniques.

Chapters covered in this class: Chapter 1, Chapter 2, Chapter 3,

Chapter 4, Chapter 6, Chapter 9,

Chapter 10, Chapter 12

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Charpter1 Introduction

School of Information Science andEngineering, Shandong University

Associate Prof., Deqiang Wang

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Outline

Evolution of Telecommunications

Simple Telephone Communication

Basics of a Switching System

Switching Systems

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Terminology

Subscriber

Source

Destination

Signaling

Point-to-point link Fully connected

networks

Switching system,

switching office,exchange

Control functions

Step-by-step

Crossbar systems

Stored program

control (SPC) Space division

switching

Time division

switching Trunk

Subscriber line

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Terminology

Simplex

communication Half-duplex

communication

Full-duplexcommunication

Sidetone

Inlets/Outlets

Switching Network

Folded network

Nonblocking Network

Blocking Network Blocking Probability

Busy time traffic

Erlang

Transit exchange Nonfolded network

Subscriber loopsignaling

Interexchange signaling

Intraexchange orregister signaling

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Terminology

Terminology

Direct control Common control

Manual switching

Local batteryexchange

Central batteryexchange

Urban networks

Metropolitannetworks

Rural networks

Long distance/tollnetworks

Wide area networks

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1.1 Evolution of Telecommunications

Full connected network

Number of subscribers: NNumber of links:N(N-1)/2Cost Efficiency: low(expensive)

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1.1 Evolution of Telecommunications

Subscriber interconnection using aswitching system

Switching System

S1 S2 SN-1 SN

Number of subscribers:

NNumber of links:N

Cost Efficiency:high(cheap)

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1.1 Evolution of Telecommunications

Classification of switching systems

Switching system

manual automatic

Electromechanical Electronic

Step-by-step Crossbar

Space division switching Time division switching

Digital Analog

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1.1 Evolution of Telecommunications

Telecommunication network structure

SS1

SS3 SS4

SS2

Subscriberlines

Trunks

Trunks

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1.1 Evolution of Telecommunications

Communication systems Electrical communication system Wired or Wireless

Optical communication system

Wired or Wireless

Links between network nodes Trunks

Subscriber lines Each link deploys some kind of

communication technology

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1.1 Evolution of Telecommunications

Service Specific Networks

Telegraph networks

Telex networks

Telephone networks Data networks

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1.2 Simple Telephone Communication

Simplex telephone circuit

Microphone Earphone

V

L

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1.2 Simple Telephone Communication

Duplex telephone circuit

Earphone

Earphone

Microphone

MicrophoneV

L

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1.2 Simple Telephone Communication

Telephone circuit with sidetone coupling

Subscriber Exchange

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1.3 Basics of Switching System

Elements of switching system

Switching network subsystem(交换网络子系统)

Signaling subsystem(信令子系统)

Control subsystem(控制子系统)

Accessary circuits（辅助电路）

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SwitchingNetwork

TrunkInterface

Subscriber

LineInterface

ServiceCircuit

Interface

TrunkInterface

Subscriber

LineInterface

ServiceCircuit

Interface

SubscriberAnd

Service

LineScanning

AndDistributor

TrunkCircuit

ScanningAndDistributor

Units

Control

Operator Console

J

UNCTOR

s

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1.3 Basics of Switching System

Model of a Switching network

Switching network is a component of theswitching system

Elements of a switching network

Function: Establish a electrical pathbetween a given inlet/outlet pair

SwitchingMatrix/Network

NInlets

MOutlets

Symmetric network:N=M

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1.3 Basics of Switching System

Inlets/outlets connections

Four types of connection:

Local call(本局呼叫), outgoing call(出局呼叫),Incoming call(入局呼叫),Transit call(转接呼叫)

SwitchingMatrix/Network

IncomingTrunks

OutgoingTrunks

SubscriberInlets

SubscriberOutlets

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1.3 Basics of Switching System

Nonfolded network（无折叠网络）

All the inlets/outlets are connected toIncoming Trunks/Outgoing Trunks

(For Transit Exchange)

Switching

Matrix/Network

N

IncomingTrunks

N

OutgoingTrunks

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1.3 Basics of Switching System

Control Subsystem

Distinguish the relationship betweeninlets/outlets and subscribers/trunks

Interpret the signaling information received

Sense the end of information transfer

Establish / release connections

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1.3 Basics of Switching System

Signaling

Function: help exchanges to establishconnections between subscriberscorrectly.

Category Subscriber loop signaling

Interexchange signaling

Intraexchange or register signaling

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1.4 Switching Systems

Manual switching system

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1.4 Switching Systems

Step-by-step & Crossbar

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1.4 Switching Systems

SPC exchange 程控 换机

SPC: Stored program control (存 程序控制)

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1.4 Switching Systems

ATM Switch

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1.4 Switching Systems

Optical Switch

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1.4 Switching Systems

Router

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Assignment

Ex. 6

Ex. 13