CHAPTER CHAPTER

Practical Ethernet Practical Ethernet ImplementationImplementation

Chapter Objectives• Provide a background on Ethernet itself and

describe its characteristics• Explain the practical implementation of various

Ethernet LANs– 10BaseT, 10Base2 and 10Base5– Show sample networking devices and network

connections

• Introduce the 100 Mbps Ethernet that is also known as fast Ethernet

• Discuss the various operating systems for Ethernet networks

Chapter Modules

• Background on Ethernet• Ethernet Basic Characteristics• Overview of Implementation• IEEE Implementation of 10BaseT• IEEE Implementation of 10Base2• IEEE Implementation of 10Base5 • Fast (100 Mbps) Ethernet Networks• Network Operating Systems for Ethernet

Networks

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MODULE

Background on Ethernet

Module Objectives

• Describe Ethernet in general• Trace the origin of Ethernet • Discuss the current status and

speeds

Ethernet Defined

• A highly standardized popular network architecture

• Based on the CSMA/CD transmission protocol

• It is a logical bus network that is implemented both as a physical star and a physical bus network

• Governed by the IEEE 802.3 standard

Origin

• CSMA/CD originated in Univ. of Hawaii in the 60s

• Cabling and signaling schemes were invented at Xerox

• Subsequently standardized by a group of companies– Xerox, Intel and DEC

Current Status

• Highly standardized• Standards set by IEEE 802

committee– IEEE 802.3

• Standards exists for different speeds of Ethernet implementations

Current Speeds

• 10 Mbps Ethernet– Example: 10BaseT

• 100 Mbps Ethernet– Example: 100BaseTX

• 1 Gigabit Ethernet– New and evolving network technology

• 10 Gigabits Ethernet is currently emerging

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MODULE

Ethernet Basic Characteristics

Module Objectives

• Topology• Cabling• Communication channels• A typical Ethernet frame• Access method and speed• IEEE 802 implementations

Topology

• Logical bus• Physical implementation

– Either Star or Bus– Each has its own advantage

Cabling

• Popular– Unshielded Twisted Pair (UTP)

(10baseT)• Different categories for different speeds

– Thin coaxial (10base2)• Others

– Thick coaxial (10Base5)– Shielded Twisted Pair (STP)– Optical Fiber (10baseFL)

Communication Channels

Network Cable

Single ChannelBaseband Technology

Ethernet Frame

A Typical Ethernet Frame Format

Preample

Receiver’s address

Sender’s address

Frame Type

CRC Trailer

Ethernet II Frame Format used for TCP/IP Communication

Frame Components

• Preamble– Start of frame indicator

• Destination address• Source address• Type

– Network layer protocol identifier• Trailer

– CRC Error checking code

Access Method and Speed

• IEEE 802.3– 10 Mbps

• IEEE 802.3u– 100 Mbps– Also known as fast Ethernet

• IEEE 802.3z– 1 Gbps– Also known as gigabit Ethernet

• IEEE 802.3ae– 10 Gbps

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MODULE

Overview of Implementations

Module Objectives

• List 10 Mbps IEEE implementations• Discuss 100 Mbps implementations• Show typical star and bus

implementations

10 Mbps IEEE 802.3 Implementations

• 10BaseT– Twisted pair implementation

• 10Base2– Thin coaxial implementation

• 10Base5– Thick coaxial implementation

• 10BaseFL– Fiber implementation

100 Mbps IEEE 802 Implementations

• 100BaseTX– Twisted pair implementation

• 100BaseT4– Uses two pairs of regular Cat 3 wires to

transmit at 100M bps

• 100VG AnyLAN– Twisted pair implementation with variation

to the 100BaseTX implementation

• The network of choice at present is– Gigabit Ethernet that is gradually replacing

100BaseTx networks

A Typical Star Ethernet LAN Configuration

Client ServerClient

NIC NIC NICNIC

Hub

RJ 45 Connection

Twisted Pair Wire Cat 5e (1000baseT)

A Typical Bus Ethernet LAN Configuration

Client ServerClient

Thin coaxialcable (10base2)T-Connector

Terminator

NIC NIC NICNIC

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MODULE

IEEE Implementation of 10BaseT Star Networks

Module Objectives

• 10BaseT implementation hardware• Implementation rules

– Length limitation and use of repeaters

• Implementation in a building• An actual 10BaseT configuration

10BaseT Implementation Hardware Requirements

• 10BaseT NIC• Hub

– May act as a multi-port repeater

• UTP or STP wiring– RJ 45 based

Actual Implementation Hardware

Hub

CablesNetworkCards

10BaseT Implementation Rules

• Maximum length of a 10BaseT segment– 100 meters (328 feet)

• Maximum number of computers supported in the LAN– 1024

Length Limitation

Client Server

Hub

< 328 feet< 328 feet

Use of Repeaters for Length Extension

Server

HubIf the distance is greater than 328 feet,a repeater can be used to extend the distance.

Repeater

Use of Fiber Line Drivers for Length Extension

Server

Switch If the distance is greater than 328 feet,a fiber-optic line driver can be used to extend the distanceto several km.

Fiber Driver

Fiber Driver

Implementation in a Building

HubPunch Down Client

Client

ServerWiring Rack(Wiring Closet)

Switch

Backbone

UTP

Installation in a Building

• Wiring closet is a reserved space in the building for housing wiring hubs

• Wiring rack• Hubs and switches• UTP cables are run to the wall• UTP connection is run from the wall

to the desktop using a patch cable

An Actual Star Ethernet LAN Configuration

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MODULE

IEEE Implementation of 10Base2 Bus Networks

Module Objectives

• Briefly outline the hardware needed to implement a 10Base2 network

• Discuss the 10base2 implementation rules such as those relating to maximum segment length, minimum distance between nodes etc.

10Base2 Implementation: Hardware Requirements

• 10Base2 NIC• 10Base2 cable

– Thin coaxial cable

• BNC T connectors• BNC terminators• BNC barrel connectors, if necessary

– Usage must be kept to a minimum, if not avoided

Actual Implementation Hardware

A Simple 10Base2 Implementation

Maximum Segment Length

Minimum Cable Length

10Base2 Implementation Rules

• Maximum segment length – 185 meters (607 feet)

• Minimum cable length– 0.5 meters (20 inches)

• Maximum number of computers per segment– 30

Length Limitation

> 20 inches

< 607 feet

5-4-3 Segmentation Rule

• To build larger networks, segments can be combined together based on the 5-4-3 rule

• 5 Segments– A 10Base2 LAN can consists of 5 segments

• 4 Repeaters– 4 repeaters are used to form the 5 segments

• 3 segments with computers– 3 of the segments can have stations attached

A Sample 5-4-3 Implementation

Repeater

Repeater

Repeater

S1

S2

S3

S4

S5Repeater

Extension of the 10Base2 LAN

• A combined effect of the 4 repeaters is to extend the overall length of the network

• Maximum length– 3035 feet

Variations to the Rule

• In practice, variations to the rule exist for practicality

• Such implementations can therefore be considered as nonconforming with IEEE

• The implication – Interoperability with other conforming devices

is not guaranteed– The functional features are the responsibility

of the manufacturer of the nonconforming device

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MODULE

Sample Implementations of 10base2

Module Objectives

• Implementing 10Base2 using switches

• Implementation in a building• Variations in 10Base2

configuration• 10Base2 and 10BaseT

internetworking

Implementing 10Base2 LANs Using Switches

Switch

S1 S2 S3

10Base2 Implementation in a Building

Router

S1S2 S3

Backbone

Variations in Ethernet Bus LAN Configuration

10Base2 and 10BaseT Internetworking

Client Server

Hub

Client Client Server

Transceiver

10Base2

10BaseT

AUI

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MODULE

IEEE Implementation of 10Base5 Bus Networks

Module Objectives

• Give an overview of 10Base5 hardware• Discuss the implementation rules• Present a sample implementation for a

building• Include other relevant notes on

10Base5 implementation• Present an example of 10Base2 and

10Base5 integration

10Base5 Implementation Hardware Requirements

• 10Base5 NIC• Transceiver • 10Base5 cables• Transceiver cables

A Simple Implementation

Thick Coax (10Base5)Transceiver Transceiver

Client Server

Vampire Clamp

15-pin AUIConnector

10Base5 Implementation Rules

• Maximum segment length– 1,640 feet

• Minimum length between connections– 8 feet

• 5-4-3 rule holds for 10Base5 LAN as well– Maximum length in 5 segments

• 8,200 feet

Other Notes on 10Base5

• Transmission characteristics – Thicknet is better than Thinnet – Used as the Backbone

• Workability– Thinnet is better than Thicknet– Used for floor distribution

An Example of 10Base2 and 10Base5 Deployment

Building

Floor

10Base5Backbone

TransceiverRepeater

10Base2

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MODULE

Fast (100 Mbps) Ethernet LANs

Module Objectives

• 100 Mbps Ethernet variations• 100BaseTX Characteristics• A simple 100BaseTX

implementation• Media variations in implementing

100BaseX

100 Mbps Ethernet Variations

• 100VG-AnyLAN– Introduced by HP– Standardized by IEEE 802.12 group

• 100BaseTX– Also known as Fast Ethernet

100BaseTX

• A very popular implementation at present

• Still based on CSMA/CD• Baseband technology• Implementation is similar to 10BaseT• Requires better UTP cable

– Category 5– Media variations are present

A Simple 100BaseTX Implementation

Client Server

Hub

Media Based Variations of 100BaseX

• 100BaseT4– 4-pair Category 3, 4 or 5 UTP

• 100BaseTX– 2-pair Category 5 UTP or STP

• 100BaseFL– 2-strand fiber-optic cable

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MODULE

Network Operating Systems for Ethernet Networks

Module Objectives

• Microsoft operating systems– Peer-to-peer– Client-server

• Unix operating system and variations of the same

• Other operating systems

Microsoft

• Peer-to-Peer– Windows Workgroup 3.11– Windows 9x (95, 98 etc.)– Windows NT Workstation

• Client-Server– Windows NT Workstation for small LANs– Windows NT Server– Small Business Server

• A combination of NT Server, Exchange Server etc.

UNIX

• Many versions of Unix• Examples

– SCO Unix– Linux– AIX– etc.

Others

• Novel NetWare• Banyan Vines• AppleShare

– For apples on an Ethernet network

• etc.

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