Evolution of Internetworking

Copyright © 2000, Cisco Systems, Inc.ICND

Evolution of Internetworking

Data Communication Example

Data

E-mail message

Data


SegmentHeader Data

Data

E-mail message

Data

Segment


SegmentHeader Data

Data

NetworkHeader

SegmentHeader Data

E-mail message

Data

Segment

Packet


NetworkHeader

SegmentHeader

FrameTrailerData

SegmentHeader Data

Data

FrameHeader

NetworkHeader

SegmentHeader Data

E-mail message

Data

Segment

Packet

Frame(medium dependent)


Network Header

SegmentHeader

FrameTrailerData

SegmentHeader Data

Data

FrameHeader

NetworkHeader

SegmentHeader Data

0111111010101100010101101010110001

E-mail message

Data

Segment

Packet

Frame(medium dependent)

Bits

The Layered Model

Copyright © 2000, Cisco Systems, Inc..ICND

Peer-to-Peer Communications

Application

Presentation

Session

Transport

Network

Data Link

Physical

HOST A HOST B

Application

Presentation

Session

Transport

Network

Data Link

Physical

Peer-to-Peer Communications

Application

Presentation

Session

Transport

Network

Data Link

Physical

HOST A HOST B

segments

packets

frames

bits

Application

Presentation

Session

Transport

Network

Data Link

Physical

Data Encapsulation

Application

Presentation

Session

Transport

Network

Data Link

Physical

Application

Presentation

Session

Transport

Network

Data Link

Physical

Application

Presentation

Session

Transport

Network

Data Link

Physical

Data Encapsulation

Application

Presentation

Session

Transport

Network

Data Link

Physical

DataApplicationHeader

DataPresentationHeader

DataSessionHeader

Application

Presentation

Session

Transport

Network

Data Link

Physical

Data Encapsulation

Application

Presentation

Session

Transport

Network

Data Link

Physical



DataSessionHeader

DataTransportHeader

Application

Presentation

Session

Transport

Network

Data Link

Physical

Data Encapsulation

Application

Presentation

Session

Transport

Network

Data Link

Physical



DataSessionHeader

DataTransportHeader

DataNetworkHeader

Application

Presentation

Session

Transport

Network

Data Link

Physical

Data Encapsulation

Application

Presentation

Session

Transport

Network

Data Link

Physical



DataSessionHeader

DataTransportHeader

DataNetworkHeader

DataFrameHeader

Application

Presentation

Session

Transport

Network

Data Link

Physical

Data Encapsulation

Application

Presentation

Session

Transport

Network

Data Link

Physical



DataSessionHeader

DataTransportHeader

DataNetworkHeader

0101101010110001

DataFrameHeader

Application, Presentation, and Session

Layers

Copyright © 1998, Cisco Systems, Inc.ICRC_revision_11.3

Application Layer

• Selects network application to support user’s application

ComputerApplications

Word Processing

Presentation Graphics

Spreadsheet

Database

Design/Manufacturing

Project Planning

Others

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

Client/Server Process

Network Management

Others

• Text• Data

ASCIIEBCDICEncrypted

Presentation Layer

• Provides code formatting and conversion for applications

login:

• Graphics• Visual Images

PICTTIFFJPEGGIF

Presentation Layer


• Text• Data


login:

• Graphics• Visual Images

PICTTIFFJPEGGIF

Presentation Layer


• Text• Data


• Sound• Video

MIDIMPEGQuickTime

login:

Session Layer

Service Request

Service Reply

• Coordinates applications as they interact on different hosts

Transport Layer


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

Sharing a Transport Connection

• Transport segments share traffic stream

Segments

ElectronicMail

FileTransfer

ApplicationApplication

PresentationPresentation

SessionSession

TransportTransport ApplicationApplicationPortPort

ApplicationApplicationPortPort DataDataDataData

Transport to Network Layer

Routed packetsRouted packets

End-to-end segmentsEnd-to-end segments

Physical and Data Link Layers


Physical and Data-Link Standards

• Separate physical and data link layers for LAN and WAN

Physical(bits,

signals,clocking)

Data LinkData Link(frames)(frames)

LAN Data Link Sublayers

NetworkNetwork

Data LinkData Link

Physical

LAN Data Link Sublayers

• MAC refers downward to lower-layer hardware functions

Media Access Control

NetworkNetwork

Data LinkData Link

Physical

MAC

Physical and Logical Addressing

0000.0c12.3456

Physical and Logical Addressing

0000.0c12.3456

192.168.10.0

MAC Address

• MAC address is burned into ROM on a network interface card

24 bits24 bits

0000.0c12. 3456Vendor Code Serial Number

ROM

RAM

Internetworking Basics

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:

Router

Bridge ATM SwitchEthernet

SwitchHub Router

Local-Area Networks and Devices

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

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

LANs are designed to:

TokenRing

Ethernet

Token Ring

FDDI

LAN Technology Overview

FDDIDual Ring

ETHERNET CABLE• Ethernet was developed by Robert Metcalfe in 1980.

The standard IEEE802.3 specifies the Ethernet protocol.

• There are several versions of Ethernet. • Category 5 cabling is currently the most prevalent

wiring in existing buildings.• Latest versions are Fast Ethernet (100Mbps) and

Gigabit Ethernet (1000 Mbps), and 10 Gigabit Ethernet is coming.

ETHERNET CABLE

• T-568A Straight-Through Ethernet Cable

ETHERNET CABLE

• T-568B Straight-Through Ethernet Cable

ETHERNET CABLE

• RJ-45 Crossover Ethernet Cable

ETHERNET CABLE

Crossover cable use

‘Straight Through' cable use

ETHERNET CABLE

Ethernet Cable Tips• A straight-thru cable has identical ends. • A crossover cable has different ends. • A crossover is used to connect two Ethernet devices without a hub

or for connecting two hubs. • A crossover has one end with the Orange set of wires switched with

the Green set. • Odd numbered pins are always striped, even numbered pins are

always solid colored. • Looking at the RJ-45 with the clip facing away from you, Brown is

always on the right, and pin 1 is on the left. • No more than 1/2" of the Ethernet cable should be untwisted

otherwise it will be susceptible to crosstalk.• Maximum Cable length for including connectors is 100 meters (or

about 328 feet).

Cisco Icons and Symbols

Evolution of Internetworking

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