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Communication Using a

Network

Chapter 7

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Chapter 7 3

Recall

Fiber Distributed Data Interface (FDDI) provideshigh-performance and connects multiple stations atthe data transfer rate of 100 Mbps.

The two types of logical topologies are:

Token ring logical topology Token bus logical topology

Asynchronous Transfer Mode (ATM) is a networkprotocol which converts data traffic into a stream of

fixed size cell before transmission. The basic network components of AppleTalk are:

Sockets, Nodes, Network and Zones.

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Chapter 7 4

Data Communication

Transmission of information between twocomputers or nodes

Basic

Components

Sender Receiver Medium Message Protocol

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Chapter 7 5

Signaling TechniquesI

Two types of Signaling techniques: Baseband

Broadband

Baseband Signals:

Uses single frequency to transmit data

Transmit information in digital form

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Chapter 7 6

Signaling TechniquesII

Broadband Signals: Data is transmitted using more than one frequency

Uses analog signals

Adds additional information to carrier signals by

process of modulation

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Chapter 7 7

Network Interface Card (NIC)

Hardware device used to connect differentcomputers on Network

Serves as a link for sending and receiving data on

a network

MAC address is address assigned by IEEE to

identify network card

NIC Types

Ethernet Card Token Ring Card

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Chapter 7 8

Ethernet Card

Used in devices which are connected using Ethernet

technology

Two types of Ethernet network card Wired and

wireless The choice depends on type of network used

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Chapter 7 9

Types of Ethernet Card - I

10Base-5 (Thicknet) NIC

10Base-2

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Chapter 7 10

Types of Ethernet card - II

10BaseT

Fiber

optic

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Chapter 7 11

Token Ring Card

Used to connect to a token ring network Assigned a MAC address by IEEE

Maximum of two token ring

cards can be installed at anynode

Consists of 9 pin DIN

type connector which connects

card to network cable

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Chapter 7 12

Physical Connections

Physical Connections

NIC either connected on a PCI or PCI-X slot

NIC cards can be connected to an USB port or can

have a PC card connection Depends on one of the cable connectors:

BNC connector

ST-fiber optic connector

RJ-45 connector

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Chapter 7 13

Lights on NIC and hub

Different LEDs on NIC:

Link LED

ACT LED

Speed LED Collision LED

LEDs on Hub:

Power LED

Port LED

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Chapter 7 14

MAC Address

Also known as hardware or physical address

Used to identify nodes at lower levels of the OSI

model

ID assigned by IEEE Hardware address hard-coded into NIC

Nodes on network identified by MAC address

Is a 12 digit hexadecimal number (48 bit address)

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Chapter 7 15

MAC vs IP address

MAC address IP address

Functions at data link

layer

Functions at network layer

It is a physical address It is a logical address

It is fixed It changes with the

relocation of device from

one network to another

It is a 48 bit address It is a 32 bit address

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Chapter 7 16

Installing the NIC

Different factors while choosing NIC:

Bus type (Expansion slot)

Speed

Connection type (cabling) Hardware Requirements:

Pentium I/233MHz

32 MB RAM

2 GB of available hard disk

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Chapter 7 17

Direct Cable Connection

One device acts as a host and other acts as a guest Can also use infrared connection, if both nodes

have required hardware

All the latest versions of windows provide a software

which allows a user to have a direct serial-to-serial,parallel-to-parallel, or infrared-to-infrared connection

with the other PC.

To establish a connection using serial ports, a cable

known as null modem is use

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Chapter 7 18

Diagnostic and Repair of Physical

Cabling using tools Tools can be used to identify the problems and also

troubleshoot these problems

Various tools available for checking network are:

Volt-ohm meters (VOMs)

Cable-testing tool usedto measure parameters

Analog

Digital

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Chapter 7 19

Tone generators and probe I

Tone generator is a network troubleshooting tool

Consists of single or multi-tone signal, two test leads

and a 4-conductor modular cable

Acts like a radio transmitter Probe:

Works like a radio receiver

Catches a tone when placed near

wire

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Chapter 7 20

Optical tester

Fiber optic NICs mostly do not have any lights so

making the diagnosis of the problem becomes little

difficult

Optical tester is used to inspect the quality of the

connections

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Chapter 7 21

Case Study

The Bangalore branch of MoneyMaker bank is

organizing a seminar on the various developments

that have occurred in the past one year. David hascreated a presentation for this purpose which is stored

on the network server. This file can be accessed only

through David's system. But on the day of seminar, he

is unable to access the system.

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Chapter 7 22

Problem

Unable to access the file which is available on

network server

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Chapter 7 23

Solution

Verify cable connection

Verify LED status of NIC

Verify LED status of hub

The LED on NIC should be ON, once you boot theoperating system

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Chapter 7 24

SummaryI

The main components of data communication are

sender, receiver, medium and message

The data to be sent is converted into signals and

then transmitted over the network

Signaling techniques are of two types broadband

and baseband

Baseband signals transmit data at a single

frequency Broadband technique can transmit data using more

than one frequency

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Chapter 7 25

SummaryII

Network Interface Cards are devices that are usedto get connected to different computers on anetwork

Some examples of NIC are Ethernet Card and

Token Ring Card Ethernet cards support transfer rate of 10 or 100 or

1000 Mbps

MAC address is a hardware address that isembedded onto the NIC

Lower layers of OSI model identify nodes on thenetwork by their MAC address

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Chapter 7 26

SummaryIII

A connection established between two nodes by

directly connecting a cable is known as direct cable

connection.

Signals lying on the cable are absorbed by the

terminators at the end of the cable to avoid collision.

Cross over cables can be used for temporary

connection between two devices when switch or

hub is not present. Volt-ohm meters is a cable-testing tool which is used

to troubleshoot the network cabling.

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Chapter 7 27

SummaryIV

Volt-ohm meter is used to measures voltage and

resistance and to check the continuity of a cable.

Tone generator and probe is another

troubleshooting tool which has the ability to identifywires, finding open circuits and short circuits,

diagnosing crosstalk and other telecom tasks