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The Structure of the Internet The Structure of the Internet

The Structure of the Internet - PowerPoint Presentation

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The Structure of the Internet - PPT Presentation

In this lesson we will Examine the difference between the Internet the Web and the Intranet Cover packet switching and how the Internet enables the Web Starter Activity What do you do online ID: 651573

internet packet 203 123 packet internet 123 203 126 information point addresses post protocol switching networks address web network letter ttl byte

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Slide1

The Structure of the InternetSlide2

In this lesson we will…

Examine the difference between the Internet, the Web and the Intranet.

Cover packet switching and how the Internet enables the Web.Slide3

Starter Activity

What do you do online?

OMG

How would you feel if you couldn’t do any of this?

How would you cope? Slide4

Internet

Web

Intranet

The Internet houses the Web but why does the intranet overlap both?

How do these intercept?

What are their functions?

The Internet, the Web and the IntranetSlide5

Activity 1

Now we are going to fill in the gaps …Slide6

The Internet

 

This

is a

global system of networks which are connected together using a particular protocol called the

TCP/IP . This is a procedure which controls how computers send information to each other. One important feature of this system is its decentralised structure. Because there is no central point on which communications depend, the system can continue to

function

well even when some

connections

break down. Slide7

The World Wide Web

 

This application, which was created in 1989, sits on top of the

Internet

. It contains information resources in many forms (

documents written in HTML, images, music, video, etc.) which can be

linked

together. Users

can access information via a

browser

(which helps them find information, entertainment or services), or navigate between documents by clicking on

hyperlinks

.

 

Each information resource has a unique

URL

and these resources can be transferred using another protocol called

HTTP

.Slide8

Intranet

 

Many companies want to take advantage of the

networking

capabilities of computers, but also need to keep their information

restricted and secure. For this reason they often use a internal network to help them

communicate

, share information, provide computing services, or create

internal

websites. Employees of organisations can access the information in these systems, but

external

access is controlled or blocked.Slide9

The Internet…

The Resilience of the InternetSlide10

Communication and the Internet…

Protocols: Set of rules for communication

Transmission Control Protocol (TCP) and Internet Protocol (IP): Protocols for communicating across the InternetSlide11

TCP and IP

TCP: underlying layer of the Internet ensuring delivery of information

IP: Responsible for providing addresses for sending informationSlide12

IP Packets

Items that are transferred across the networks

IP Packet:

Header Actual Data

Source IP Address,

Destination IP Address,

Packet Number,

Number of packets that make up that itemSlide13

Foundations of communicating across the Internet:

Protocol are a set of rules

TCP: delivering the information

IP: Providing the addressesInformation is broken into IP PacketsQuestions?

So far…Slide14

Now to get your brains working that little bit more….Slide15

Post Office Analogy

When you send a Letter in the Post what is the process…Slide16

Digital Post Office

Write the Letter

Sign the Letter

Put it in an envelopeWrite the Address of Destination on Envelope

Place a Stamp on the EnvelopePlace Letter in Post BoxLocal Post Man picks up letter amongst others from post boxLetter goes through Sorting OfficeNew local Post Man delivers letter to destinationSlide17

Activity 2

Together, organise the slips which represent the steps for packet switching into the correct order – think about the post office analogy to help you

Slide18

Packet Switch Networks - 1

Moving a File from A to BSlide19

Packet Switching

Point A

Point BSlide20

Now Lets Give it a Go….Slide21

Packet Switching

Point A

Point BSlide22

Packet Switch Networks -

2

Routing around missing serversSlide23

Packet Switching

Point A

Point BSlide24

Packet Switch Networks -

3

Packet orderSlide25

Packet Switching

Point A

Point B

HE

LL

OSlide26

Packet Switch Networks -

4

Time-To-Live (TTL)Slide27

Packet Time To Leave (TTL)

Data packets have TTL number

TTL is number of server-to-server hops before the packet is no longer forwarded (hop limit).

A server receiving a packet reduces TTL by 1 before passing it on.A server receiving a packet with TTL discards it and sends a re-send message to the originating server (i.e. send packet again)Slide28

Point A

Point B

HE

LL

O

10

9

8

7

6

9

9

5

4

3

2

1

8

7

6

5

4

3

8

7

6

5

4

3

2

1

Packet Switching

0

Request new packet

9

8

7

6

5

4

3

10Slide29

IP Address

A

unique label assigned to each device in a computer network that uses the Internet Protocol. Does anyone know what is the most common form of IP Address and what is the newer IP Address? Slide30

IPv4

Most common Internet Protocol

Limited number of IP addresses

IPv6 – newer version (to be discussed at a later date)Slide31

IPv4

32-bits (4 bytes)

= 2

^32 different values (this is binary which will cover at a later date)Slide32

Bits/Bytes

If 32 bits = 4 bytes, so how many

bits

are there in 1 byte?Slide33

Fun Fact…

Half a Byte (4 bits) is called a Nibble!Slide34

IP Addresses

0 to 255

0 to 255

0 to 255

0 to 255

192 192 158 158

1 chunk

1 byte

1 chunk

1 byte

1 chunk

1 byte

1 chunk

1 byteSlide35

IP Addresses

192 192 158 158

Network Identifier

Host

IdentifierSlide36

IP Addresses

Are these IP addresses on the same network?

1) 126.203.123.123

and 126.203.100.100

2) 126.203.123.123 and 123.123.126.203 3)

126.203.97.54 and 126.203.123.123 Slide37

IP Addresses

Are these IP addresses on the same network?

1) 126.203.123.123

and 126.203.100.100 - YES

2) 126.203.123.123 and 123.123.126.203 - NO 3)

126.203.97.54 and 126.203.123.123 - YES Slide38

Summarise…

Can you individually write 4 or 5 points that you have learnt and can take away with you today…Slide39

Internet is the foundation

Web uses the Internet

Intranets are private networks

Communicating across the Internet:Protocol are a set of rulesTCP: delivering the informationIP: Providing the addresses

Information is broken into IP PacketsMethodology used for communicating IP Packets across the Internet is called Packet Switching

To Summarise…Slide40

To Summarise…

IP Addresses are used to identify a device on a network

IPv4 is most commonly used IP Address

IP Addresses are made up of 4 chunks, 32-bitsFirst 2 Chunks = Network IdentifierSecond 2 Chunks = Host Identifier

*Key Terms HandoutSlide41

Any Questions?