Módulo 4: Básico de Lan

(1)

Módulo 4:

Básico de Lan

Módulo 4:

(2)

Tradução: Kleber Aparecido Tomé

Agenda

• Ethernet

• Token Ring

(3)

Tecnologias mais comuns em

Lans

• Ethernet

• Token Ring

• FDDI

Dual Ring

FDDI

Token

(4)

Ethernet

(5)

Ethernet - IEEE 802.3

• Benefícios

–

Ethernet é a mais popular tecnologia de LAN

porque encontra uma boa performance entre

velocidade, custo e facilidade de instalação.

–

Suporta teóricamente todos os protocolos de rede.

–

Instituída pela Xerox, quando da junção entre DEC

& Intel em 1980

• Revisões das Especificações da Ethernet

Fast Ethernet (IEEE 802.3u) aumento de

velocidade de 10 Mbps para 100 Mbps

(6)

Ethernet - IEEE 802.3

• Diversas variações de frames são encontradas

nesta tecnologia de LAN, fato que não

atrapalha o desenvolvimento dos cartões de

rede pelos inúmeros fabricantes.

(7)

Velocidade da LAN ( bps )

100Base5

“Base” = baseband

“Broad” = broadband

Indica o tipo do cabo

E o seu tamanho máximo.

Tamanho max. = # x 100 m

Ex. 10base5 => 5 x 100 = 500m

Ethernet Protocol Names

(8)

Ethernet e Fast Ethernet

Protocol

Max. Segment

Length (m)

Transmission

Medium

Application

10Base2

185 50-ohm coaxial

A: Link user stations

10Base5

500 50-ohm coaxial

A: Link user stations

10BaseF

Refers to 10BaseFB, 10BaseFL, and 10Base FP

10BaseFB

2000

Fiber-optic

A: Add segments

10BaseFL

1000–2000

Fiber-optic

A: Operate w/ FOIRL

10BaseFP

500 Fiber-optic

Star topo w/out repeaters

10BaseT

100 2-pairs TP

Sends link signals

10Broad36

3600

Broadband coax

A: Broadband

100BaseFX

400 2 strands of multimode fiber-optic cable

100BaseT

100 UTP

10BaseT function + more

100BaseT4

100 4 prs Cat 3-5 UTP

-100BaseTX

100 2 prs UTP or STP

(9)

O Funcionamento da Ethernet

A

(10)

O Funcionamento da Ethernet

A

B

C

D

Data Link

Network

Transport

Session

Presentation

Application

Physical

(11)

O Funcionamento da Ethernet

A

B

C

D

Data Link

Network

Transport

Session

Presentation

Application

Physical

B and C

Data Link

Network

Transport

Session

Presentation

Application

Physical

(12)

Ethernet Broadcast

D

Data Link

Network

Transport

Session

Presentation

Application

Physical

C

Data Link

Network

Transport

Session

Presentation

Application

Physical

B

Data Link

Network

Transport

Session

Presentation

Application

Physical

A

Data Link

Network

Transport

Session

Presentation

Application

Physical

(13)

A Confiabilidade da Ethernet

B

C

D

A

B

C

D

A

Figura 1

Figura 2

Colisão

(14)

Ethernet Reliability

Colisão

C

B

C

D

A

B

A

D

JAM

(15)

Ethernet Reliability

B

C

D

A

Collision

B

C

D

A

JAM

• Carrier sense multiple access with

collision detection (CSMA/CD)

(16)

As opções de Alta Velocidade da

Ethernet

• Fast Ethernet

• Fast EtherChannel

®

• Gigabit Ethernet

(17)

O que é Fast EtherChannel?

Grupo de múltiplas interfaces Fast Ethernet

operando como uma única porta lógica.

Grupo de m

ú

ltiplas interfaces

Fast Ethernet

operando como uma

ú

nica porta l

ó

gica.

• Largura de banda crescente

até 800+ Mbps

• Customizado em padrões

da Fast Ethernet

• Balanceamento de carga

através de links paralelos

• Extensiva para Gigabit

Ethernet

400 Mb

600 Mb

800 Mb

(18)

• 1000-Mbps data rate

• 802.3/Ethernet frames

• Full duplex or half duplex

• Meios de acesso em Fibra ou cabo

• 100% compatível com os já

existentes:

–

Protocolos de rede

–

Sistemas Operacionais de Rede

–

Aplicações de Redes

–

Gerenciamento de Rede

20%

80%

Workgroup

20%

80%

Backbone

(19)

Token Ring

(20)

Token Ring (IEEE 802.5)

• História

–

Desenvolvida pela IBM nos anos 70;

–

IEEE 802.5 tem especificações totalmente

compatíveis com o Token Ring

–

Segundo padrão mais popular, perdendo apenas para

a Ethernet.

• Características

–

Token determines transmission so no collisions

–

Ideal for applications (such as factory automation)

where delay must be predictable and robust network

operation is important

–

More difficult and costly than Ethernet, but little

impact as more users are added to system

(21)

Token Ring

IBM Token

Token Ring

Ring Network

IEEE 802.5

Data Rates

4 or 16 Mbps

Stations/Seg

260 STP, 72 UTP

250 Topology

Star

Not specified

Media

Twisted-pair

Not specified

Signaling

Baseband

(22)

Topologia Token Ring

• Logicamente opera como um anel,

mas fisicamente opera em configuração estrela com

a utilização do MAU ( Multistation access unit ).

Shielded or

Unshielded

Twisted-Pair

MAU

(23)

Token Ring Operation

A

T = 0

T

• Token Ring LANs continuously pass a

token or a Token Ring frame

(24)

Token Ring Operation

A

T = 0

T

Data

A

T = 1

T

• Token Ring LANs continuously pass a

token or a Token Ring frame

(25)

Token Ring Operation

A

T = 0

T

Data

A

T = 1

A

_{T = 0}

T

• Token Ring LANs continuously pass a

token or a Token Ring frame

(26)

Token Ring Summary

• Reliable transport, minimized collisions

• Token passing/token seizing

• 4- or 16-Mbps transport

• Little performance impact with increased

number of users

• Popular at IBM-oriented sites such as

(27)

FDDI

(28)

Fiber Distributed

Data Interface (FDDI)

• Fiber Distributed Data Interface (FDDI)

–

Defined by ANSI X3T9.5 spec in mid 1980s

–

100-Mbps

token-passing network

–

Fiber-optic cable with

max. distance of 2 km

–

Dual-ring architecture

for redundancy

–

Used for corporate and

carrier backbones

• CDDI

–

Implements FDDI over STP and UTP cable

–

Transmits at 100 Mbps over about 100 m

FDDI

Dual Ring

(29)

FDDI Network Architecture

• Dual-ring architecture

–

Primary ring for data transmissions

–

Secondary ring for reliability and robustness

• Components

–

Single attachment station (SAS)—PCs

–

Dual attachment station (DAS)—Servers

–

Concentrator

• FDDI concentrator

–

Also called a dual-attached concentrator (DAC)

–

Building block of an FDDI network

–

Attaches directly to both rings and ensures that any SAS

failure or power-down does not bring down the ring

(30)

FDDI Network Example

WAN

FDDI

Concentrator

SAS

DAS

Primary Ring

Secondary Ring

(31)

FDDI Summary

• Features

–

100-Mbps token-passing network

–

Single-mode (100 km), double-mode (2 km)

–

CDDI transmits at 100 Mbps over about 100 m

–

Dual-ring architecture for reliability

• Optical fiber advantages versus copper

–

Security, reliability, and performance are enhanced

because it does not emit electrical signals

–

Much higher bandwidth than copper

(32)

Summary

• LAN technologies include Ethernet,

Token Ring, and FDDI

• Ethernet

–

Most widely used

–

Good balance between speed, cost, and ease of installation

–

10 Mbps to 1000 Mbps

• Token Ring

–

Primarily used with IBM networks

–

4 Mbps to 16 Mbps

• FDDI

–

Primarily used for corporate backbones

–

Supports longer distances