ICND 1 - Capitulo 1

8/3/2019 ICND 1 - Capitulo 1

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Interconecting Cisco Network DevicesInterconecting Cisco Network Devices

INTERCONEXION DEDISPOSITIVOS DE RED CISCO

ICND 1

CAPITULO 1:CONSTRUYENDO REDES

SENCILLAS


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Interconecting Cisco Network Devices

Al completar este capitulo , estar en lacapacidad de:

Identificar los beneficios de una red de ordenadores y comofunciona.

Identificar las amenzas comunes a una red de datos y losdiferentes metodos para mitigar estas.

Identificar y comparar los modelos de comunicacin entrehost OSI y TCP / IP

Describir el direccionamiento IP y como se pueden obtenerlas direcciones IP.

Describir el procedimiento que TCP usa para establecerconexin

Objectivos


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Al completar este capitulo , estar en lacapacidad de:

Describir el proceso de entrega de paquetes host a host.

Describir como opera Ethernet en la Capa 1 y 2 del modeloOSI

Explicar como se conecta una LAN Ethernet.

Objectivos (cont.)


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Definiendo componentes deRed (Cont.)

Floor 2

Floor 1

Server Farm

BranchOffice

Telecommuter

ISDN

Remote Campus


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Acceso y conexin a redes dedatos

Internet

Telecommuter

Branch Office

Modem or ISDN TA

Mobile User

Main Office


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Seguridad en la red

Core_Server

core_sw_a

ISDN Cloud

core_sw_bcore_sw_b

Leased Line/Frame Relay

Internet



MODELOS DE COMUNICACIN

Capas deAplicacin(Upper layers)

Sesin

Presentacin

Applicacin

Modelo OSI



MODELOS DE COMUNICACIN

Modelo OSI

Capas deFlujo de datos(Data FlowLayers)

Transporte

Enlace de datos

Red

Fisica

Sesin

Presentacin

ApplicacinCapas deAplicacin

(Upper layers)



Roles de las capas de

ApplicacinTelnetFTP

Interfaz de usuario

EJEMPLOS

Applicacin



TelnetFTP

ASCIIEBCDICJPEG

Interfaz de usuario

Como se presentanlos datos

Procesos especialestales como Cifrado

EJEMPLOS

Presentacin

Applicacin


Applicacin



TelnetFTP

ASCIIEBCDICJPEG

Mantener diferentesapliciones separadas

Sistemas Operativos/Agenda de aplicaciones

de acceso

EJEMPLOS

Sesion

Applicacin


Applicacin

Como se presentan

los datosProcesos especialestales como Cifrado

Presentacin

Interfaz de usuario



TCPUDPSPX

802.3 / 802.2HDLC

EIA/TIA-232V.35

IPIPX

EJEMPLOS

Rol de las capas de flujos de

datos

Transporte

Fisica

Entrega de datos segura y no segura Correccin de errores antes de

retransmitir

Combina bits en bytes y

bytes en tramas Acceso al medio usando MAC address Error detection not correction

Move bits between devices Specifies voltage, wire speed and

pin-out cables

Red

Entrega direccionamiento lgicoLos Enrutadores determinan el mejorcamino a seguir

Enlace dedatos



TCPUDPSPX

802.3 / 802.2HDLC

EIA/TIA-232V.35

IPIPX

Presentation

Application

SessionEXAMPLES

Role of Data Flow Layers

Reliable or unreliable delivery Error correction before retransmit

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

Transport

Data Link

Physical

NetworkProvide logical addressing whichrouters use for path determination



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

Encapsulating Data



Upper Layer Data

De-encapsulating Data

LLC Hdr + IP + TCP + Upper Layer Data

IP + TCP + Upper Layer Data

TCP+ Upper Layer Data

Upper Layer Data

0101110101001000010

Transport

Data Link

Physical

Network

Presentation

Application

Session



Physical Layer Functions

Defines

Media type

Connector type

Signaling type

802.3

Physical


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Physical Layer: Ethernet/802.3

Hub

Host

10Base2Thin Ethernet

10Base5Thick Ethernet

10BaseTTwisted Pair


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Hubs Operate at Physical layer

A B C D

Physical

All devices in the same collision domain

All devices in the same broadcast domain

Devices share the same bandwidth


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Hubs: One Collision Domain

More end stations means

more collisions CSMA/CD is used


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Data Link layer FunctionsDefines

Physical source anddestination addresses

Higher layer protocol(Service Access Point)associated with frame

Network topology

Frame sequencing

Flow control

Connection-orientedor connectionless

DataL

ink

Phys

ical

EIA/TIA-232

v.35

802.2

802.3


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DataSource add FCSLengthDest add

Variable266 4

0000.0C xx.xxxx

Vendorassigned

IEEE assigned

MAC Layer - 802.3Data Link Layer Functions (cont.)

Preamble

Ethernet IIuses Type

here and

does not use802.2.

MAC Address

8# Bytes


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DataDest

SAP

Source

SAP

DataSource add FCSLengthDest add

Variable11

802.2 (SAP)

MAC Layer - 802.3

Data Link Layer Functions (cont.)

Ctrl

1 or 2

3 2

Preamble

DataDest SAP

AASource SAP

AA

Variable11

802.2 (SNAP)

Ctrl

03

1 or 2

OR

OUIID

Type

# Bytes

# Bytes


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Each segment has its own collision domain

All segments are in the same broadcast domain

Data Link

Switches and BridgesOperate at Data Link Layer

OR1 2 3 1 24


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Switches

Each segment has itsown collision domain

Broadcasts areforwarded to allsegments

Memory

Switch


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Network Layer Functions

Defines logicalsource anddestination

addressesassociated with aspecific protocol

Defines pathsthrough network

Interconnectsmultiple data links

Network

IP, IPX

DataLink

Physical

EIA/TIA-232

v.35

802.2

802.3


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DataSource

address

Destination

address

IP

Network Layer Functions (cont.)

Header

172.15.1.1

NodeNetwork

LogicalAddress

Network Layer End Station Packet


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11111111 11111111 00000000 00000000

10101100 00010000 01111010 11001100

BinaryMask

BinaryAddress

172.16.122.204 255.255.0.0

172 16 122 204

255

Address Mask

255 0 0

Network Host


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Routing Table

NET INT Metric

124

S0S0E0

100

1.0 4.0

1.3

E0

4.3

S0

2.2

E0

2.1

S0

4.1

4.2

1.1

1.2

Routing Table

NET INT Metric

124

E0S0S0

001

Logical addressing allows for hierarchical network Configuration required

Uses configured information to identify paths to networks



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Routers: Operate at theNetwork Layer

Broadcast control

Multicast control

Optimal pathdetermination

Traffic management

Logical addressing

Connects to WANservices


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Transport Layer Functions

Distinguishes betweenupper layer applications

Establishes end-to-end

connectivity betweenapplications

Defines flow control

Provides reliable orunreliable services fordata transfer

Net

work

IPXIP

Trans

port

SPXTCP UDP


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Reliable Transport Layer

Functions

Synchronize

Acknowledge, Synchronize

Acknowledge

Data Transfer

(Send Segments)

Sender Receiver

Connection Established


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Using Telnet to Connect to Remote Devices


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Viewing Telnet Connections


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Using the ping and traceCommands

Tests the connectivity and path to a remote device

Router###ping 10.1.1.10

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 10.1.1.10, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 4/4/4 ms

Router#trace 192.168.101.101

Type escape sequence to abort.

Tracing the route to 192.168.101.101

1 p1r1 (192.168.1.49) 20 msec 16 msec 16 msec2 p1r2 (192.168.1.18) 48 msec * 44 msec

Router#


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core_sw_a

ISDN CloudLeased Line/Frame Relay

Cabling the Campus

Legend

FastEthernet/

Ethernet

ISDN

Dedicated

Core_Server

LAN Ph i l L


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Physical

Data Link(MAC layer)

LAN Physical LayerImplementations

Physical layer implementations vary

Some implementations support multiplephysical media

10B

aseT

802.3

10B

ase5

10B

ase2

802.3 Specificationsfor 10MB Ethernet

802.3u Specificationsfor 100MB (Fast)

Ethernet

10B

aseF

DIXStandard


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Positioning Ethernet in theCampus

AccessLayer

DistributionLayer

Core Layer

Ethernet 100BaseTPosition

Gigabit Ethernet Position

Access

Layer

DistributionLayer

Core Layer

Provides connectivty

between the end userdevice and the accessswitch.

Not typically used at thislayer.

Gives high-performance PC and

workstations 1000-Mbps access tothe server.

Provides connectivity between accessand distribution layers. Providesconnectivity from the distribution to

core layer. Provides connectivity fromthe server block to the core layer.

Provides inter-switch connectivity.Not typically used at thislayer.

C i Eth t M di


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Comparing Ethernet MediaRequirements

100 BaseT

Duplex media-interfaceconnector(MIC) ST

Diff ti ti b t


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Differentiating betweenConnections

AUI connectorsare DB15

ISO 8877 (RJ-45)connectors and jacksare slightly larger than

RJ-11 phoneconnectors and jacks

Fiber Connector Port


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UTP Device

The RJ-45 Connector

1

8

8 Pair 4 R4

12

3

4

5

6

7

Wire PairT is TipR is Ring

Pair 3 T2

Pair 3 R2

Pair 2 T3

Pair 1 R1

Pair 1 T1

Pair 2 R3

Pair 4 T4

Pin

UTP I l t ti


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UTP ImplementationStraight-through

Wires on cable endsare in same order

Pin Label1 RD+2 RD-3 TD+

4 NC5 NC6 TD-7 NC8 NC

Pin Label1 TD+2 TD-3 RD+

4 NC5 NC6 RD-7 NC8 NC

Server/Router

81

wg

g bwo

wb

o brwbr

1

8

Straight-through Cable

81Hub/Switch

81

wg

g bwo

wb

o brwbr

UTP I l t ti


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UTP ImplementationCrossover

Some wires on cableends are crossed

8 1

wo

ob wg

wb

gbr wbr

Cable 10BaseT/100BaseT Crossover





Crossover Cable

1

8 1

8

8 1

wg

gwb

wo

b obr wbr

Hub/Switch Hub/Switch


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Cabling the Campus

Determine the physical media used- 100MB or 1000MB

Indicates what type of CAT cable is required

Locating interfaces on the chassis- determine if oneor both ports have an X

Indicates if need crossover or straight-through cable

1000 MbpsCat 5, 6

Crossover

100 MbpsCat 5

Crossover1000 MbpsCat 5,6

Straight-through

10 MbpsCat 3, 4, 5

Straight-through

100 MbpsCat 3, 4, 5

Straight-through

ICND 1 - Capitulo 1

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