Networksakali2/TB143/Lecture10.pdf · In Networking, Protocols are: •Agreements that describe how things work. •Industry-wide frameworks that describe every aspect of communications

Copyright © 2005 Heathkit Company, Inc. All rights reserved.

Unit 10

Networks

2

The basic components

of a network:

• Connections (Physical Medium)

• Protocols (Common language)

• Services (Clients, Servers, and

Files)

3

The Client is the computer

requesting the use of a resource.

May I have

Worksheet-101?

Client Server

4

The Server is the computer

providing the resource.

Sure, here it Sure, here it

is!

Worksheet 101Worksheet-101

Client Server

5

In some networks, every computer

acts as both Client and Server.

Client &

Server

Client &

Server

Client &

Server

6

Peer-to-Peer Network

Client &

Server

Client &

Server

Client &

Server

7

Peer-to-Peer Network

• No centralized data access.

• Security handled by assigning

each resource a password.

8

Peer-to-peer works best with a a

small number of computers.

9

One computer can act as server

for several clients.

Server

Client

Client

Client Client

Client

Client

10

Client/Server Network

• Centralized data access.

• Centralized security.

• Centralized administration,

record keeping, and control.

11

Larger networks require the

client/server arrangement.

12

The Physical Medium is the

channel the data travels

between computers.

Physical MediumPhysical Medium

Client Server

13

The Physical Media can be:

• Wire

• Fiber Optic Cable

• Wireless Link (RF or Infrared)

• Hardware devices such as

network cards, hubs, routers, etc.

14

The common language is the

Network Protocol.

May I have

Worksheet-101?

Client Server

Sure, here it Sure, here it

is!

15

Protocol

• A signed document containing the

record of the points on which

agreement has been reached by

negotiating parties.

• The code of ceremonial forms and

courtesies accepted as proper and

correct in official dealings.

16

In Networking, Protocols are:

• Agreements that describe how things

work.

• Industry-wide frameworks that

describe every aspect of

communications between computers.

• Grouped together into Protocol

Suites.

17

The main Protocol Suites:

• NetBEUI – Small Microsoft networks.

• SPX/IPX – Primarily Novell networks.

• TCP/IP – Must be used if the network is to connect to the Internet.

18

One of the most basic

ways to classify networks

is by their topology.

19

Topology refers to the

way the computers in the

network are connected to

each other.

20

The most common

topologies are:

• Bus

• Star

• Ring

• Mesh

21

Bus Topology

―T‖―T‖ ―Backbone‖―Backbone‖

22

Bus Topology

• A single cable interconnects all workstations.

• The cable is terminated at both ends.

23

Star Topology

24

Star Topology

All workstations connect to a single central hub.

25

Ring Topology

26

Ring Topology

• Backbone is a ring.

• Each workstation connects only to two other

workstations.

27

Mesh Topology

28

Mesh Topology

Net-1

Net-4 Net-3

Net-2

29

The Internet is an example of a Mesh

topology.

InternetInternet

30

Another way of

classifying networks is

by their size or

geographical span.

31

The most common size

classifications are the:

• Local Area Network (LAN)

• Metropolitan Area Network

(MAN)

• Wide Area Network (WAN)

32

The Local Area Network The Local Area Network

(LAN)(LAN)

33

Metropolitan Area Network

(MAN)

34

Wide Area Network

WANWAN


Networking

Components

36

Components

• Network Operating System

• Interface Cards

• Cables

37

Network Operating System

(NOS)

vs.

desktop Operating System

(OS)

38

NOS provides improved

security• User-level Security

• Server authenticates:

– User name

– User password

– User location

• Server determines which resources the user may access.

• Simplifies security for the user.

39

The NOS allows sensitive

resources to be maintained in a

centralized/secure location.

40

The NOS provides

improved performance.

• Client is relieved of the burden

of server

• Server can be optimized

• Adds administration and

management capabilities.

41

The NOS provides

better administration.

• Centralized security

• Centralized data

• Consistent policies

• Administrative tools

• Accountability

42

The NOS allows scalability

• The client/server network grows gracefully.

• A server may handle over 50 clients.

• Additional servers can be added.

• Specialized servers

– File server

– Print server

– Communications Server

43

Disadvantages of the NOS

• More expensive

• More complex

• Requires administration.

44

Major Network

Operating Systems

• Unix

• Novell NetWare

• Windows NT Server

45

Unix

• Multitasking, Multi-user OS

• Influential in evolution of the Internet

• Uses TCP/IP

• Clients communicate with Server using

Terminal Emulation

46

Linux

• Smaller, easier to use version of Unix

• Easily adapted to individual computers

or as server in a small network

• Uses the command line as the user

interface.

• Offered with a graphical user interface.

47

Novell’s NetWare

• Text-based operating system

• Supports all Windows-based

client computer operating systems

• IPX/SPX is the primary NetWare

protocol

48

Windows NT

• 32-bit network operating system

• First to use a graphical user interface

• Not as feature-rich as Unix and

NetWare

• Supports a wide range of network

clients

49

The Network Interface

Card is also called:

• The Network Card

• The Network Adapter

• The Network Adapter Card

• The NIC

50

The NIC is the main interface

between the computer and the

network cable.

51

Parallel data into serial data.

CPUMemory

Computer

NIC

1001100110011001

Cable

1-0-0-1-1-0-0-1

52

Considerations when

selecting the NIC:

• Type of cable connection

• Type of Address/Data Bus

• The method used to configure the

card.

53

The NIC must match the cable.

RJ-45RJ-45

BNCBNC

54

RJ-45 ConnectorRJ-45 Connector

55

The NIC must match the

Address/Data Bus of the computer.

ISAISA

PCIPCI

56

Installing the NIC in

the computer.

• NIC installed inside the computer.

• Normally plugs into a bus slot.

• Some are built right into the motherboard.

• Plug-in boards must be configured correctly.

57

NIC Configuration Methods

• Plug-and-Play

• EEPROM

• Jumper pins

58

Preparing to Install the NIC

• Ensure there is an open bus slot.

• Ensure the adapter is compatible.

• Ensure there are system resources available.

• Ensure all installation items are available.

• Ensure all software is available.

59

Installing the NIC Hardware

• Configure the NIC to available resources.

• Use a ground strap.

• Remove cover from the computer.

• Remove rear panel slot cover plate.

• Remove card from its antistatic bag and immediately plug it into motherboard.

• Secure card slot cover plate to computer.

60

Installing the NIC Software

• Loading the device driver used

by the NIC.

• Loading any utilities supplied

with the NIC.

61

NIC Device Driver

• Supports communication between

the NIC and OS.

• Automatically installed and

configured if both NIC and OS

support PnP.

• In other cases, driver loaded from

floppy or CD supplied with NIC.

62

A more recent device

driver may be available

at the website of the NIC

manufacturer.

63

Troubleshooting the NIC

• Is NIC talking to the

motherboard?

• Is the NIC working internally?

• Is the NIC communicating with

the external network?

64

LEDs

LinkLink

ActivityActivity

65

Twisted-Pair Cable

• UTP—Unshielded Twisted-Pair

• STP—Shielded Twisted-Pair

66

Twisted-Pair Cable

STPSTP STPSTPUTPUTP

Foil

Shield

Foil

ShieldWire

Shield

Wire

Braid

Shield

Foil

Shield

Foil

Shield

67

10BaseT Ethernet uses

Unshielded Twisted Pair

(UTP) cable.

68

RJ-45 Connector

Strain Relief CrimpStrain Relief Crimp

ContactsContacts

LatchLatch

WiresWires

69

Twisted-Pair Advantages

• UTP is inexpensive.

• Workstations isolated from each other by central hub.

• Easy to add workstations to segment.

• Easier to route than coaxial cable.

• Easier to troubleshoot than coaxial cable network.

70

Twisted-Pair Disadvantages

• UTP cable is susceptible to RFI/EMI.

• Suffers crosstalk between wire pairs.

• Poor conductor; attenuates signal more quickly than coax.

• Maximum segment length half of coax.

• STP cable more expensive than UTP cable or coax.

• Difficult to work with shielding.

71

EIA/TIA Cable Categories

• Category 1—Voice-grade UTP phone

• Category 2—Data-grade UTP, 4 Mbps




72

Category 3 Cable

• Common data-grade cable.

• Four unshielded twisted-pair

wires.

• Transmission rates up to 10 Mbps.

73

Category 5 Cable

• Data-grade cable.

• Official transmission rates up to

100 Mbps.

• Four unshielded twisted-pair wires.

74

Two Bus Technologies:

• 10Base5 or Thicknet

• 10Base2 or Thinnet

75

Coaxial Cable Characteristics

Sleeve Wire Braid Dielectric Center Conductor

FoilRG-8 Thicknet Cable

RG-58 Thinnet Cable

76

Coax Advantages

• Resistant to RFI.

• Good conductor.

• Longer network segments.

• Thinnet: easy/inexpensive workstation interconnection.

• Thicknet: stronger, more durable than any other network cable.

77

Coax Disadvantages

• Each segment must be terminated.

• Break in cable disables entire segment.

• Difficult to add workstations to a thinnet segment.

• Thicknet: difficult to use, heavy shield braid and foil.

• Thicknet: requires special piercing tap and transceiver.

78

What’s in a name?

• 10Base5

• 10Base2

79

The number on the left is

the speed of the LAN.

10 Base 5

10 Base 2

Speed in

Megabits

Per Second

Speed in

Megabits

Per Second

80

The number on the right is the

length of the LAN segment.

10 Base 5

10 Base 2

Length of

in Hundreds

Length of

Segment

in Hundreds

Of Meters

81

The word in the middle

signifies the type of signal.

10 Base 5

10 Base 2

Type of Signal

82

BasebandBaseband

BroadbandBroadband

Signal 1

Signal 2

Signal 3

83

RG-58, 10Base2, or Thinnet CableRG-58, 10Base2, or Thinnet Cable

RG-8, 10Base5, or Thicknet CableRG-8, 10Base5, or Thicknet Cable

84

The RG-58’s lighter shield still

provides good protection

against electrical noise.

85

Fiber Optic CablesFiber Optic Cables

86

Cable Construction

87

Fiber end-view

88

The Glass FiberThe Glass Fiber

89

ST connector

90

ST Connector


LAN

Communication

92

LAN Technologies:

• Ethernet

• Token Ring

• ARCnet

• LocalTalk

93

Ethernet• Developed by Xerox in early ’70s.

• Has become most popular networking technology in use today.

• A variety of speeds and cabling options have evolved.

• It is fast, inexpensive, and flexible.

• It continues to evolve.

• Majority of new networks use Ethernet.

94

Networking is all about

sending data from one

location to another.

Worksheet 101?

May I have

Worksheet-101?Sure, here Sure, here

it is!

PC-1 PC-2

95

The CPU routinely sends

data from one place to

another.

CPU

96

But when multiple

computers are involved, a

new series of problems arise.

PC-1 PC-2 PC-3 PC-4 PC-5

97

How do you keep all the

computers from transmitting

at the same time?


98

Is this for

me?

Is this for

me?


99

Who sent Who sent

this?


100


Ah, it’s from PC-1.

Gee, I wonder if it is correct.

101


Here’s the ten

you wanted!

Here’s the ten

gigabyte folder

you wanted!

102

Large files are broken into

manageable chunks called packets.

Large File

Packets

103

How do you keep two

computers from transmitting

at the same time?


104

Carrier Sense

Multiple Access/

Collision Detection

(CSMA/CD)

105

Carrier Sense

• Each computer attached to the

network examines the cable before

transmitting.

• If it senses traffic on the cable, it

waits until the traffic clears before

transmitting.

106

Multiple Access

• All computers on the network have equal access to the cable.

• A lowly desktop has the same access as the Windows NT Server.

• Access is on a first-come, first-served basis.

• The only consideration is: ―Is someone else using the cable?‖

107

Collisions still happen


108

The computers involved

in the collision detect the

collision.


Wow! That’s

said!

Wow! That’s

not what I

said!

Wow! That’s

said!

Wow! That’s

not what I

said!

109

The computers involved in the

collision back off for a random

length of time.


I’ll back off for I’ll back off for

―x‖Microseconds

I’ll try ― ‖ I’ll try ―y‖

Microseconds.

110

Collisions are a natural

characteristic of Ethernet.


Documents

Networksakali2/TB143/Lecture10.pdf · In Networking, Protocols are: •Agreements that describe how things work. •Industry-wide frameworks that describe every aspect of communications