internet working concept overview

© 2000, Cisco Systems, Inc. 2-1

Chapter 2

Internetworking Concepts Overview

© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—2-2

ObjectivesObjectives

On completion of this chapter, you will be able to perform the following tasks:• Describe how data traffic is exchanged

between source and destination devices

• Identify the roles and functions of a hub, switch, and router, and where they best fit in the network

• Select the appropriate Cisco equipment for a given set of network requirements


Defining Components of the Network

Defining Components of the Network

Main OfficeBranch Office

Home Office

Mobile Users

Internet


Floor 2

Floor 1

Server Farm

Defining the Components of a Network (cont.)

Defining the Components of a Network (cont.)

Branch Office

Telecommuter

ISDN

Remote Campus


Network Structure Defined by Hierarchy

Network Structure Defined by Hierarchy

Distribution Layer

Core Layer

AccessLayer


Access Layer CharacteristicsAccess Layer Characteristics

End station entry point to the network

Access Layer


Distribution Layer Characteristics

Distribution Layer Characteristics

• Access Layer Aggregation Point

• Routes traffic

• Broadcast/Multicast Domains

• Media Translation

• Security

• Possible point for remote access

Distribution Layer


Core Layer Characteristics Core Layer Characteristics

• Fast transport to enterprise services

• No packet manipulation

Core Layer


OSI Model OverviewOSI Model Overview

Application (Upper) Layers

Session

Presentation

Application


OSI Model OverviewOSI Model Overview

Data Flow Layers

Transport Layer

Data Link

Network Layer

Physical

Application (Upper) Layers

Session

Presentation

Application


Role of Application LayersRole of Application Layers

TelnetFTP

User Interface

EXAMPLES

Application


TelnetFTP

ASCIIEBCDICJPEG

User Interface

• How data is presented• Special processing such as encryption

EXAMPLES

Presentation

Application



TelnetFTP

ASCIIEBCDICJPEG

Keeping different applications’ data separate

User Interface


Operating System/Application Access Scheduling

EXAMPLES

Session

Presentation

Application



Keeping different applications’ data separate

User Interface


TelnetFTP

ASCIIEBCDICJPEG

Operating System/Application Access Scheduling

Transport Layer

Data Link

Network Layer

Physical

EXAMPLES

Session

Presentation

Application



Role of Data Flow LayersRole of Data Flow Layers

EIA/TIA-232V.35

EXAMPLES

Physical • Move bits between devices• Specifies voltage, wire speed and

pin-out cables


802.3 / 802.2HDLC

EIA/TIA-232V.35

EXAMPLES


Data Link

Physical

• Combines bits into bytes and bytes into frames

• Access to media using MAC address• Error detection not correction

• Move bits between devices• Specifies voltage, wire speed and

pin-out cables


802.3 / 802.2HDLC

EIA/TIA-232V.35

IPIPX

EXAMPLES


Network

Data Link

Physical




pin-out cables

Provide logical addressing which routers use for path determination


TCPUDPSPX

802.3 / 802.2HDLC

EIA/TIA-232V.35

IPIPX

EXAMPLES


Transport

Data Link

Physical

• Reliable or unreliable delivery• Error correction before retransmit




pin-out cables

Network Provide logical addressing which routers use for path determination


TCPUDPSPX

802.3 / 802.2HDLC

EIA/TIA-232V.35

IPIPX

Presentation

Application

SessionEXAMPLES


• Reliable or unreliable delivery• Error correction before retransmit




pin-out cables

Transport

Data Link

Physical

Network Provide logical addressing which routers use for path determination


Encapsulating DataEncapsulating Data

Transport

Data Link

Physical

Network

Upper Layer Data

Upper Layer DataTCP Header

DataIP Header

DataLLC Header

0101110101001000010

DataMAC Header

Presentation

Application

Session

Segment

Packet

Bits

Frame

PDU

FCS

FCS


Upper Layer Data

De-encapsulating DataDe-encapsulating Data

LLC Hdr + IP + TCP + Upper Layer Data

MAC Header

IP + TCP + Upper Layer Data

LLC Header

TCP+ Upper Layer Data

IP Header

Upper Layer Data

TCP Header

0101110101001000010

Transport

Data Link

Physical

Network

Presentation

Application

Session


Application

Presentation

Session

Transport

Network

Data Link

Physical

OSI Model PDU Functional Responsibilities Examples

Written Exercise: OSI Model Written Exercise: OSI Model

internet working concept overview

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