Transcript
Page 1: First IEC 1 Chapter9_10 Circuit & Packet Switching  Communication Network  Circuit Switching  Message Switching  Packet Switching

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First IEC

Chapter9_10Circuit & Packet Switching

Communication NetworkCircuit SwitchingMessage SwitchingPacket Switching

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First IEC

Communication Network

Communication Network 의 필요성 Full mesh 의 Connection

완전환 연결을 위해 N(N-1)/2 개의 전송 링크가 필요 각 Station 은 (N-1) 개의 Interface 가 필요

/

Page 3: First IEC 1 Chapter9_10 Circuit & Packet Switching  Communication Network  Circuit Switching  Message Switching  Packet Switching

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First IEC

Communication Network

Network 를 이용한 Connection 하나의 Interface 를 통하여 불특정 단말간의

데이터 교환

Page 4: First IEC 1 Chapter9_10 Circuit & Packet Switching  Communication Network  Circuit Switching  Message Switching  Packet Switching

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First IEC

Communication NetworkNetwork 의구성

Network 는 Node 와 Link 로 구성 Network 에서 Information 를 한 지점에서

다른 지점으로 전달하려면 Switching 이 필요

UNI: User to Network InterfaceNNI: Node to Node Interface

Page 5: First IEC 1 Chapter9_10 Circuit & Packet Switching  Communication Network  Circuit Switching  Message Switching  Packet Switching

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First IEC

Communication Network

Communication Network 의 종류

Switching Methods

Circuit Switching Message SwitchingPacket Switching

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First IEC

Circuit Switching

Circuit Switching 두 Station 간에 직접 물리적인 연결을 설정 연결된 circuit 을 독점적으로 사용 Circuit Switching 의 Communication 3

단계 Circuit Establishment Data Transfer Circuit Disconnect

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First IEC

Circuit Switching두 Station 간의 Dedicated Path 설정

Circuit Establish A→Ⅰ→Ⅱ→Ⅲ→D 순으로 회선 설정

Data Transfer Data Transmission

Circuit Disconnect(A or D) A→Ⅰ→Ⅱ→Ⅲ→D 순으로 회선 해제

Page 8: First IEC 1 Chapter9_10 Circuit & Packet Switching  Communication Network  Circuit Switching  Message Switching  Packet Switching

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First IEC

Circuit SwitchingCircuit Switch

Input Link 와 Output Link 간의 회선 연결 Switch Control Interface 를 통하여 스위치 연결 제어 연결의 요청은 signaling 을 사용하여 동적으로

제어하거나 관리시스템에서 제어

Switch Control

Input Output

Page 9: First IEC 1 Chapter9_10 Circuit & Packet Switching  Communication Network  Circuit Switching  Message Switching  Packet Switching

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First IEC

Circuit SwitchingPublic Switched Telephone

Network Subscribers: Network 에 접속되는 장치 Local loop[subscriber loop] : Subscribers 와

End Office 간의 연결 Exchanges: Switching Center Trunks: Switch 간의 연결 링크

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First IEC

Message SwitchingData Communication 을 위한 교환 방식메시지 단위로 Store and Forwarding 데이터

교환Message 의 Header 에는 Address 가 필요

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First IEC

Packet Switching

비음성 전송 Idle Time 이 존재 Data 가 bursty 한 경향 회선 교환의 경우 회선의 효율이 떨어짐

Circuit Switching 의 단점 회선의 효율이 낮음 연결되는 두 Station 간에 단일 데이터 전달 융통성이 떨어짐 전송의 우선 순위가 없음

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First IEC

Packet Switching

Packet Switching Message 를 일정한 크기의 Packet 으로

분할하여 전송 Packet 단위로 Store and Forwarding

데이터 교환 대화형 Data Communication 에 적합

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First IEC

Packet Switching

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First IEC

Packet Switching

Store

and

Forward

Switch

Switch

Switch

Switch

ComputerTerminal

CPUMemory

I/O

PacketSwitch

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First IEC

Packet Switching

Packet Switching Technique

Packet Switching

Datagram

SwitchedVirtual Circuit

Virtual Circuit

PermanentVirtual Circuit

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First IEC

Packet SwitchingDatagram Technique

Connectionless 방식 각 Packet 마다 독립적으로 경로 배정 모든 Packet 에 Address 보유 필요 순서에 맞지 않게 Destination 에 도달 가능

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First IEC

Packet SwitchingDatagram Technique 의 Multi

Channel Packet 은 TDM 또는 FDM Multiplexing

에 의해 동시에 전송

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First IEC

Packet SwitchingVirtual Circuit Technique

Connection Oriented 방식 Packet 전송 전에 논리적인 연결 설정 필요 연결 설정 후 , 각 Packet 은 Header 내에

가상 회선 Identifier 보유 Virtual Circuit 상에서 Packet 의 전달 순서

보장 Virtual Circuit 의 설정 방법에 따라

SVC(Switched Virtual Circuit) 연결 설정 절차를 필요 시에 수행

PVC(Permanent Virtual Circuit) 가상회선이 두 사용자 사이에 항상 설정

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First IEC

Packet Switching

SVC(Switched Virtual Circuit)

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First IEC

Packet Switching

PVC(Permanent Virtual Circuit)

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First IEC

Packet Switching

Packet Switching Technique Operation

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First IEC

Packet Switching

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First IEC

Packet SwitchingPacket Size 의 효과

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First IEC

Packet Switching

Operation of Switching Technique Propagation Delay

Signal 이 한 Node 에서 다른 Node 로 도달하는데 걸리는 시간

Transmission Time Sender 가 Data 의 한 블록을 보내는데 걸리는 시간

Processing Delay[Node Delay] 한 Node 가 Data 를 교환할 때 필요한 처리를

수행하는데 소요되는 시간 Queuing Delay

Packet 이 각 Node 에서 Queue 에 들어가 전송 전에 기다려야 하는 시간

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First IEC

Packet Switching

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First IEC

Packet Switching

Circuit Switching vs Virtual Circuit Physical path 와 Virtual route

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First IEC

Packet Switching

Dedicated 와 shared

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First IEC

Packet SwitchingCircuit Switch DG, Packet

Switch VC, Packet Switch

Dedicated Path No dedicated Path

No dedicated Path

No buffering Buffering Buffering

Call setup required

No call setup Call setup required

Busy No busy, delayed

No busy, delayed

Electromechanical SW

Computer SW Computer SW

No speed/code conversion

Speed/code conversion

Speed/code conversion

Fixed BW for Real time traffic

Dynamic BW Dynamic BW for non-real time data, reliable

PSTN X.25 networks


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