计算机科学与工程系-网络笔记重点1

GraphicSymbols

BridgeSwitchRouterAccessISDNMulti-layerNetwork

serverswitchswitchswitch

3aDSU/CSU|

PersonalFileServerDataServiceUnit/ModemWebServer

computerChannelServiceUnit

WAN“cloud”HubNetworkCloudor

(ColorMayVary)BroadcastDomain

EthernetFastEthernetSerialLineCircuitSwitched

Line

PhysicalandData-Link

Standards

LANWAN

X.25

Dial

LinkISDN

onSDLCHDLC

Demand

FramePPP

Relay

V.24

日A/TIA-232

日A-530

G.703

HSSI

V.35

日A/TIA-449

•SeparatephysicalanddatalinklayersforLANandWAN

LANDataLinkSublayers

MACFrame802.2LLCPacketorDatagram

•LLCrefersupwardtohigher-layersoftwarefunctions

•MACrefersdownwardtolower-layerhardwarefunctions

LLCSublayerFunctions

•Enableupperlayerstogainindependence

overLANmediaaccess

•Allowserviceaccesspoints(SAPs)from

interfacesublayerstoupper-layer

functions

FindingtheMACAddress

HostY呼—LF

..HostZL,,7

BDroadcast....HostZ

——MAC?o

「Al-------1I

Response

Example1:DestinationlocalHostYHostZ

MACMAC

HostZ

Ethemet/802.3Operation

DBandC

ApplicationApplication

Presentation'Presentation

SessionSession

TransportTransport

NetworkNetwork

DataLinkDataLink

PhysicalPhysical

1.■

Ethernet/802.3Broadcast

ABCD

ApplicationApplicationApplicationApplication

PresentationPresentation)Presentation)

SessionSessionSession______Session

TransportTransportTransportTransport

NetworkNetworkNetwork_____Network

DataLinkDataLinkDataLinkDataLink

PhysicalPhysicalPhysicalPhysical

EthernetFrameVariations

PreambleDASATypeDataFCS

86624

EthernetFrame

802.2

PreambleDASALengthHeaderFCS

andData

86624

802.3Frame

EthernetFrameVariations

802.3Frame

Ethernet/802.3Reliability

PhysicalLayer:Token

Ring/802.5

Twisted-Pair

•Logicallyaring,butphysicallyastarconfiguration

toMAUrelays

TokenRing/802.5Operation

•TokenRingLANscontinuouslypassa

tokenoraTokenRingframe

TokenRing/802.5Reliability

FrameStatusField

ACrrACrr

00Destinationnotfound

01Copiedbutnotacknowledged

10Unabletocopydatafromframe

11Stationfoundorframecopied

toanotherringbyabridge

Sendingstationreceivesstatusinformation

inaframe

FDDIDual-RingReliability

Whenafailure...wrapprimary

domainandsecondary

occurs...rings...

...wrapprimary...maintaining

andsecondarynetworkintegrity

rings...

WANTechnologyOverview

SDLC

HDLC

LAPB

PPP

X.25

FrameRelay

ISDN

PhysicalLayer:WAN

日A/TIA-232

V.35

X.21

HSSI

Others/

A『

---------------------------CSU/DSU

V

(Modem)

DTEDCE

DataTerminalEquipmentDataCircuit-TerminatingEquipment

Endoftheuser担deviceEndoftheWANprovider■担

ontheWANlinksideofthecommunicationfacility

DataLinkLayer:WAN

Protocols

(Modem)

(Modem)

CSU/DSU

*

,SDLCSynchronousDataLinkControl

,HDLCHigh-LevelDataLinkControl

•LAPBLinkAccessProcedureBalanced

,FrameRelayimplifiedversionofHDLCframing

•PPPPoint-to-PointProtocol

•X.25Packetlevelprotocol(PLP)

•ISDNIntegratedServicesDigitalNetwork(data-link

signaling)

AnOverviewofWide-Area

Services

•AsimplifiedlookinsidetheWANcloud

•TherouteralsousesaWANcentraloffice

InterfacingWANService

Providers

•Providerassignsconnectionparametersto

subscriber

SubscribertoProvider

Interface

DataTerminalEquipmentDataCircuit-TerminatingEquipment

Endoftheuser'sdeviceEndoftheWANprovider's

ontheWANlinksideofthecommunicationfacility

—>1IModem

X^CSU/DSU

DTEDCETA/NT1

DTEDCEDTE

•DTE/DCEThepointwhereresponsibilitypasses

UsingWANServiceswith

Routers

X.25/LAPB

FrameRelay

ISDN/LAPD

SDLC

HDLC

PPP

DDR

WANFrameFormatSummary

CiscoHDLC

FFllagAddressControlPProprietaryDDataFCSFlag

SDLCandLAPB

FlagAddressControlDataFCSFlag

•FormatsassumeframingondedicatedWANfacilities

AnOverviewofPPP

Multipleprotocol

encapsulationsusing

、NCPsinPPP

,PPPcancarrypacketsfromseveralprotocolsuitesusing

NetworkControlPrograms(NCPs)

•PPPcontrolsthesetupofseverallinkoptionsusingLCP

•PPPdatalinkwithnetwork-layerservices

PPPLCPConfigurationOptions

FeatureHowItOperatesProtocol

Requireapassword

AuthenticationPAP

PerformChallengeHandshakeCHAP

Compressdataatsource;Stackeror

CompressionreproducedataatPredictor

destination

ErrorMonitordatadroppedonlinkQuality

Detection

AvoidframeloopingMagicNumber

MultilinkLoadbalancingacrossMultilink

multiplelinksProtocol(MP)

PPPAuthenticationOverview

PPPSessionEstablishment

1LinkEstablishmentPhase

2OptionalAuthenticationPhase

3Network-LayerProtocolPhase

•TwoPPPauthenticationprotocols:

PAPandCHAP

SelectingaPPP

AuthenticationProtocol

RemoteRouterPAPCentral-SiteRouter

(SantaCruz)2-WayHandshake(HQ)

"santacruz,boardwalk"

Accept/Reject

a

Hostname:santacruzusernamesantacruz

Password:boardwalkpasswordboardwalk

•Passwordssentincleartext

•Peerincontrolofattempts

SelectingaPPPAuthentication

Protocol(cont.)

CHAP

RemoteRouterCentral-SiteRouter

(SantaCruz)3-WayHandshake(HQ)

Challenge

Response

-A

Hostname:santacruzAccept/Rejectusernamesantacruz

Password:boardwalkapasswordboardwalk

•UseSecret?

•Knownonlytoauthenticatorandpeer

FrameRelayOverview

DCEor

Frame

RelaySwitch

DTEor

CPECSU/DSU

router^K

Token

、Ring,FrameRelayworkshere.

•Virtualcircuitsmakeconnections

•Connection-orientedservice

FrameRelayTerminology

LMI^^□□□□□

□□□□□

]□□□

□□□□□

!□□□

现口□口

500=Active力口口口

胪□□□□400=Active

DLCI=500

Local/LocalAccess

AccessLoop=64kbps

Loop=T1

DLCI=400

LocalAccess

□□□□□

□□□□□

□□□□□Loop=64kbps

□□□□□

□□□□□

FrameRelayOperation

DLCI400=ActiveeDLCI100=ActiveA

Hello,Iam172.16855onDLCI100,whoareyou?*

FrameRelayOperation

(cont.1

DLCI=400

Cloud

FrameRelayMap

DLCI400Active

Hello,IamonDLCI400.

FrameRelayMap

DLCI100Active

Hello,IamonDLCI100.

■>

)KeepaliveAKeepalivefyT

ConfiguringBasicFrameRelay

Rei.10.3Router

□OODRei.11.2Router

□□□□

□□□□

□□□□

interfaceSeriall

interfaceSeriall

ipaddress

ipaddress

encapsulationframe-relay

encapsulationframe-relay

bandwidth56

bandwidth56

!frame-relayImi-typeansi

!

routerrip

routerrip

network

network

•InverseARPisenabledbydefaultsoitdoesnotappearinconfigurationoutput.

ConfiguringOptional

Commands

DLCI=100

IPaddress=/24

DLCI=110

IPaddress=/24

interfaceSeriall

ipaddress

encapsulationframe-relay

bandwidth56

frame-relaymapip110broadcastCISCO

!

routerrip

network

ConfiguringOptional

Commands

Router（con耀-if）#

ipbandwidth-percenteigrpas-numberpercent

•DefinesthepercentageofbandwidththatEIGRPshould

useforroutingtraffic

Router（con耀-if）#

keepalivenumber

•Establishestheintervalatwhichkeepalivesaresentby

therouter

Router（conO-if）#

frame-relaylocal-dlcinumber

DefineslocalDLCInumber

VerifyingFrameRelay

Operation

Router#

showinterfacesserial•DisplaysDLCIandLMI

Router#information

showframe-relaypvc•DisplaysPVCtraffic

statistics

Router#

showframe-relaymap•Displaystheroutemaps

Router#(staticordynamic)

showframe-relayImi•DisplaysLMIinformation

SelectingaFrameRelay

Star(HubandSpoke)

CablingtheCampus

LANPhysicalLayerImplementations

•Physicallayerimplementationsvary

•Someimplementationssupportmultiple

physicalmedia

DataLink

(MAClayer)802.3

t

e

nXX4

r25TFTFT

eeeeeeee

thsssssss

Physicalaaaaaaa

EBBbbb

00BB000

1100000

11111

DIX802.3Specifications802.3uSpecifications

Standardfor10MBEthernetfor100MB(Fast)

Ethernet

PositioningEthernetintheCampus

Ethernet10BaseTFastEthernet

PositionPosition

AccessProvidesconnectivityGiveshigh-performancePCand

Layerbetweentheenduserworkstations100-Mbpsaccesstothe

deviceandtheaccessserver.

switch.

Distribution

NottypicallyusedatthisProvidesconnectivitybetweenaccess

Layer

layer.anddistributionlayers.Provides

connectivityfromthedistributionto

corelayer.Providesconnectivityfrom

theserverblocktothecorelayer.

CoreLayerNottypicallyusedatthisProvidesinter-switchconnectivity.

layer.

ComparingEthernetMedia

Requirements

10Base510BaseT100BaseTX100BaseFX

日A/TIACat日A/TIACat62.5/125

Media50-ohm

coax(thick)3,4,5UTP5UTPmicronmulti­

2pair2pairmodefiber

Maximum

Segment500meters100meters100meters400meters

Length

TopologyBusStarStarPoint-to-Point

Duplexmedia­

ISO8877ISO8877interface

ConnectorAUI

(RJ-45)(RJ-45)connector

(MIC)ST

Differentiatingbetween

Connections

ISO8877(RJ-45)

connectorsandjacks

areslightlylargerthan

<i.r(工

0s匕

ooE±HEbiBJ-(t5cphoraeooOCDOEIHEBMEI

------oooL3」

『6般andjacksr

7c，O0^15KEM

81baC)CZ)[vnl

Z

ZO

H8

TxRx

UTPDevice

WirePair

TisTip

PinRisRing

1Pair3T2

2Pair3R2

3Pair2T3

4PairlR1

5Pair1T1

6Pair2R3

7Pair4T4

TheRJ-45Connector8Pair4R4

UTPImplementationStraight-

through

Cable10BaseT/

Straight-throughCable

100BaseTxStraight-through

Hub/SwitchServer/Router

PinLabelPinLabel

1RD+^—------1TD+

2RD-<-------2TD-

3TD+------—►3RD+

4NC4NC

5NC5NC

6TD-------—►6RD-

7NC7NCWiresoncableends

8NC8NCareinsameorder

UTPImplementationCrossover

Cable10BaseT/

100BaseTCrossoverCrossoverCable

Hub/SwitchHub/Switch

PinLabelPinLabel

RD+

RD-

TD+

NC

NC

TD-

NCSomewiresoncable

8NC

8NCendsarecrossed

CablingtheWAN

WANPhysicalLayer

Implementations

•Physicallayerimplementationsvary

•Cablespecificationsdefinespeedoflink

ey

D.ma

D.alISDNBRI(withPPP)

D.re

FR

日A/TIA-232RJ-45

日A/TIA-449NOTE:Pinoutsare

X.21V.24V.35differentthanRJ-45

HSSIusedincampus

DifferentiatingBetweenWAN

SerialConnectors

Routerconnections

Enduser

device

s

s

x

NetwoiconnectionsattheCSU/DSU

SerialImplementationof

DTEversusDCE

DataTerminalEquipmentDataCommunicationsEquipment

Endoftheuser'sdevice・EndoftheWANprovider's

ontheWANlinksideofthecommunicationfacility

•DCEisresponsibleforclocking

FixedInterfaces

EthernetSynchronousISDNSystem

AUILEDserialLEDsBRILEDOKLED2500ROUter—rearView

oooaoooo0

□CDOCDC3OOOCCDQC3OQQC3OOpooccOQOCDQOCDC：

OOOCDCDOCDCD0

□OOOOOOOC|OC3ODOCDOOO|pooocOOOOOOOU0

AUI---------0

SERIAL0SERIAL1BRH|CONSOLEAUX0

V0

0

0

0

A

Console

EthernetSynchronousportOn/offPower

AUIportserialports(RJ-45)switch

(DB-15)(DB-60)ISDNAuxiliaryport

BRIport(RJ-45)

(RJ-45)

SerialWANportscanbefixed

ModularInterfaces

WAN

SerialWANportscanbemodularInterface

1603Router—rearview

臧照昭。。赧褥

Hiuuuiuy-----------------------------/1----------------

JO3V8E_E_LHEbHE_L0*WA-)(I2OMBH102VL)

Ethernet10BaseTEthernetAUIISDNBRIS/TConsoleModule

3640Router——slotssiot2

的赢面a@1陆阳出逅）口@刚掰棚质幽◎\

SSOOOQ2OOOOOCD13mg格格^0昌占吕昌冷廿叼g

Slot1SlotOPowersupply

CablingRoutersfbrISDN

Connections

DetermineifyouneedaBRIS/TorUInterface

♦outershaveoneorbothtypesofports

,

O吕卷）—西OOOBiO

B1O©lO

°CDOB2OBRuIIL

"八~)B273)

CMIOZJ

SEEMANUALBEFOREINSTALLATIONSEEMANUALBEFOREINSTALLATIONH

『--Idj

NoteportLabel

(g)®®

(iCHASETETHERNET。AU)(ISUNBRI0S/T)B

0K

0Jgpq一14VDC

T-Console

EthernetISDNBRI

portportport

CablingRoutersfbrISDN

Connections(cont.)

CiscoRouter

)

ISDNBRIport

!!!WARNING!!!

DonotconnectacableintoanISDNportunlessitis

fromanISDNswitchorISDNwalljack.

Ifyouconnectacablefromanyotherdeviceintothe

BRIport,youwillruinthenon-ISDNdevice.

SettingupaConsoleConnection

PC

DevicewithconsoleRJ-45-to-RJ-45

rollovercable

RJ-45-to-DB-9adapter

(labeledTERMINAL)

-PCsrequireanRJ-45toDB-9orRJ-45toDB-25adapter

-COMportsettingsare9600bps,8databits,noparity,1stopbit,

noflowcontrol

-Thisprovidesout-of^bandconsoleaccess

-AUXswitchportmaybeusedformodem-connectedconsole

VisualObjective

wg_pc_a

——且设一一

A/B

eO/1

console

(1x)

faO/26(Ax)v'eO/2(2x)

wg_sw_awg_ro_a

wg_pcI

eO/1

faO/26(Ax)(1x)IIconsole

eO/2(2x)eOLL/FR

wg_ro_

wg_sw_lbriO/|

ISDN

faO/1faO/12

faO/24(1x)(12x)s3/0”

s1/0-s2/3

(24x)

fa0/23(23x)faO/O

core_servercoreswacore_ro

ReviewQuestions

1.DiscussthreestandardsonwhichEthernetLANimplementa