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강 사 : 전 필 복 [CCIE # 4244]

Connecting People To InformationConnecting People To Information

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Curriculum Related to ICRC

MSSCMSSC

Cisco 3800Cisco 3800Inst. & Config.Inst. & Config.

CIDCID

SNAMSNAM

CMTDCMTD IMCRIMCR

AS5200AS5200 CITCIT

MCRIMCRI

ACRCACRC

ICRCICRC

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Course Prerequisites

• Basic knowledge of networking concepts and terminology

• Basic knowledge of internetworking concepts

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FDDI

TokenRing

FDDI

TokenRing

Router

Ethernet (or LAN)

Token Ring

FDDI/CDDI

Network or

wide-area network

Serial

Graphic Symbols

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Router

ATM switch

Personal computer

Workstation

Macintosh

Network management

station (CiscoWorks)

Graphic Symbols (cont.)

Bridge

Ethernet switch

Router/hub

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1980s and 1990s: Internetworks

TokenRing

Private Netsand

Internet

FDDI

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BridgeATM

SwitchEthernetSwitch

Hub Router

Local-Area Networks and Devices

• Operate within a limited geographic area• Allow multiaccess to high-bandwidth media• Control the network privately under local admin

istration• Provide full-time connectivity to local services• Connect physically adjacent devices

LANs are designed to:

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Wide-Area Networks and Devices

• Operate over geography of telecommunication carriers

• Allow access over serial interfaces operating at lower speeds

• Control the network subject to regulated public services

• Provide full-time and part-time connectivity

• Connect devices separated over wide, even global, areas

WANs are designed to:

ATM SwitchRouter Modem CSU/DSU TA/NT1

Multiplexer

statmux

Comm.Server

WAN BandwidthSwitch

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1990s: Global Internetworking

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Network Manager Tasks and Goals

DesignDesignOperationsOperations

TroubleshootingTroubleshooting

Connectivity

Reliable Performance

ManagementControl

Flexibility

The Layered Model

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Why a Layered Network Model?

• Reduces complexity

• Standardizes interfaces

• Facilitates modular engineering

• Ensures interoperable technology

• Accelerates evolution

• Simplifies teaching and learning

Application

Presentation

Session

Transport

Network

Data Link

Physical

7

6

5

4

3

2

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Layer FunctionsNetwork processes to applicationsData representation

Interhost communication

End-to-end connections

Addresses and best path

Access to media

Binary transmission

Application

Presentation

Session

Transport

Network

Data Link

Physical

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6

5

4

3

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Peer-to-Peer Communications

HOST A HOST B

segments

packets

frames

bits

Application

Presentation

Session

Transport

Network

Data Link

Physical

Application

Presentation

Session

Transport

Network

Data Link

Physical

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Application

Presentation

Session

Transport

Network

Data Link

Physical

Data Encapsulation

DataApplicationHeader

DataPresentationHeader

DataSessionHeader

DataTransportHeader

DataNetworkHeader

0101101010110001

DataFrameHeader

Application

Presentation

Session

Transport

Network

Data Link

Physical

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Data Encapsulation Example

Network Header

SegmentHeader

FrameTrailer

Data

SegmentHeader

Data

Data

FrameHeader

NetworkHeader

SegmentHeader

Data

0111111010101100010101101010110001

E-mail message

Data

Segment

Packet

Frame(medium dependent)

Bits

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Remaining Chapter Sequence

Application

Presentation

Session

Transport

Network

Data Link

Physical

7

6

5

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3

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NetworkApplications

End-to-EndServices

Data Transmission

Routing

Application,

Presentation,

and Session

Layers

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ComputerApplications

Word Processing

Presentation Graphics

Spreadsheet

Database

Design/Manufacturing

Project Planning

Others

Application Layer

• Selects network application to support user’s application

NetworkApplications

Electronic Mail

File Transfer

Remote Access

Client/Server Process

Information Location

Network Management

Others

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Application Layer (cont.)

NetworkApplications

Electronic Mail

File Transfer

Remote Access

Client/Server Process

Information Location

Network Management

Others

InternetworkApplications

Electronic Data Interchange

World Wide Web

E-Mail Gateways

Special-Interest Bulletin Boards

Financial Transaction Services

Internet Navigation Utilities

Conferencing (Video, Voice, Data)

Others

• Internetwork applications can extend beyond the enterprise

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• Graphics• Visual Images

PICTTIFFJPEGGIF

Presentation Layer

• Provides code formatting and conversion for applications

• Text• Data

ASCIIEBCDICEncrypted • Sound

• VideoMIDIMPEGQuickTime

login:

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• Network File System (NFS)• Structured Query Language (SQL)• Remote-Procedure Call (RPC)• X Window System• NetBios Names• Internet Browsers• DNA Session Control Protocol (SCP)

Session Layer

Service Request

Service Reply

• Coordinates applications as they interact on different hosts

Transport Layer

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Transport Layer Overview

• Segments upper-layer applications

• Establishes an end-to-end connection

• Sends segments from one end host to another

• Optionally, ensures data reliability

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Sharing a Transport Connection

• Transport segments share traffic stream

Segments

ElectronicMail

ElectronicMail

FileTransfer

FileTransfer

TerminalSessionTerminalSession

ApplicationApplicationApplicationApplication

PresentationPresentationPresentationPresentation

SessionSessionSessionSession

TransportTransportTransportTransport ApplicationApplicationPortPort

ApplicationApplicationPortPort DataDataDataData

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Connection-Oriented Sessions

Synchronize

Synchronize

Acknowledge

Negotiate Connection

Data Transfer

(Send Segments)

Sender Receiver

Connection EstablishedConnection EstablishedConnection EstablishedConnection Established

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Flow Control

Buffer Full

Process Segments

Buffer OK

Buffer Full

Process Segments

Buffer OK

Transmit

Not ReadyStop

ReadyGo

Resume Transmission

Sender Receiver

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Reliability with WindowingWindow size = 1

Send 1 Receive 1Ack 2

Send 2 Receive 2Ack 3

Send 1

Send 2

Receive 1

Receive 2

Window size = 3

Send 3 Receive 3

Ack 4

Send 4

Sender Receiver

Sender Receiver

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Positive Acknowledgment

Sender Receiver

Send 2Send 1

Send 3Ack 4

Send 5Send 4

Send 6Ack 5

Send 5Ack 7

1 2 3 4 5 6 1 2 3 4 5 6

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Transport to Network Layer

Routed packetsRouted packetsRouted packetsRouted packets

End-to-end segmentsEnd-to-end segmentsEnd-to-end segmentsEnd-to-end segments