Understanding the Internet
I can describe different parts of the Internet. (yr 5)
I can tell you the Internet services I need for
different purposes. (yr 6)
I can describe how information is transported on
the Internet. (yr 6)
Based on:
‘What is the Internet? How does it work ?’, Helen Greer
http://community.computingatschool.org.uk/resources/2114
Modelling the Internet, Barefoot Computing
http://barefootcas.org.uk
What is the
internet?
The internet is a vast
network of computers
and other devices
connected together
across the planet. The
internet is the
hardware.
http://www.youtube.com/watch?v=WwyJGzZmBe8
There and Back Again: A Packet's
Tale - How does the Internet work?
Is that all that
happens?
1.
Web Page
Client
www.school.org.uk
Web Server
1.
• Type in a web address on client
• Client goes to web server
• Sends back web page
Is that all that happens?
No!
2.
Web Page
www.school.org.uk
Web Server
Client
LAN
/Home
Router
2.
• Type in a web address on client
• Client goes to Home router
• Home router goes to web server
• Sends back web page
Is that all that happens?
No!
Internet Service
Provider (e.g. Talk Talk, BT, Sky)
3.
Web Page
ISP Router
www.school.org.uk
Web Server
Client
LAN/Home
Router
3.
• Type in a web address on client
• Client goes to Home router
• Home router goes to ISP
• ISP goes to web server
• Brings back web page
Is that all that happens?
No!
4.
Internet Service
Provider
(e.g. Talk Talk, BT, Sky)
ISP Router
Domain
Name
Server
Web Page
79.110.49.10
www.school.org.uk
Web Server
Client
LAN/Home
Router
4.
•
•
•
•
Type in a web address on client
Client goes to Home router
Home router goes to ISP
ISP takes address to Domain name
server
• DNS turns web address into IP
address to go to correct web server
• Sends back web page
Is that all that happens?
No!
5.
Internet Service
Provider
Domain Name
Server
Web Page
79.110.49.10
WAN Router
ISP Router
WAN Router
Web Server
WAN Router
WAN Router
www.school.org.uk
WAN Router
WAN Router
WAN Router
Client
WAN Router
WAN Router
LAN/Home
Router
WAN Router
5.
•
•
•
•
•
Type in a web address on client
Client goes to Home router
Home router goes to ISP
ISP takes address to Domain name server
DNS turns web address into IP address to
go to correct web server
• Sends back web page from WAN router
to WAN router to WAN router
Is that all that happens?
No!
Internet Service
Provider
Packets
Domain Name
Server
79.110.49.10
WAN Router
ISP Router
WAN Router
Web Server
WAN Router
WAN Router
www.school.org.uk
WAN Router
WAN Router
Web Page
WAN Router
Client
WAN Router
WAN Router
LAN/Home
Router
WAN Router
6.
•
•
•
•
•
Type in a web address
Client goes to Home router
Home router goes to ISP
ISP takes address to Domain name server
DNS turns web address into IP address to go to
correct web server
• Splits web page into packets
• Brings back packets from WAN router to WAN
router to WAN router
• Puts packets together
Is that all that happens?
No!
7.
Internet Service
Provider
Domain Name
Server
Web Page
79.110.49.10
WAN Router
ISP Router
WAN Router
Web Server
WAN Router
WAN Router
www.school.org.uk
WAN Router
WAN Router
WAN Router
Client
WAN Router
WAN Router
LAN/Home
Router
WAN Router
7. •
•
•
•
•
•
•
•
•
Type in a web address on client
Client goes to Home router
Home router goes to ISP
ISP takes address to Domain name server
DNS turns web address into IP address to go to
correct web server
Splits web page into packets
Sends back packets from WAN router to WAN
router to WAN router
finding quickest route if one router isn’t
working
Puts packets together
Is that all that happens?
No!
But we are
getting close!
What are clients?
Clients are computers
setup to access services
through the internet. For
example, we use a client to
view web pages, videos or
read emails.
Examples of clients include
PCs, laptops, mobile phones,
some TVs, games consoles
and tablet devices.
Client
Client
What are routers?
Routers are devices which
help information get to where
it needs to be across the
internet. They route it.
To help routers send the
information to the correct
location, all devices on the
internet have an internet
protocol (IP) address.
Router
What are servers?
Servers are computers setup to
provide internet services, such as
the world wide web, e-mail or
online games.
Some of these computers are
web servers - they store
information in web pages which is
called the WWW.
There are also domain
name servers (DNS), which
we’ll learn more about next.
Serve
r
What are DNS?
Domain name servers
(DNS) are a type of server which
provide the IP address of the web
server holding the website you
want to view.
For example, a DNS could
provide the IP address for the
server holding the
www.barefootcas.org.uk
webpage, which is
109.109.131.16.
DNS
Match the description.
A. A computer setup to provide
services on the internet.
B. A computer used to access
services on the internet.
Client
Server
Client
C. A computer setup to provide
the IP address of web servers
holding web pages.
Router
D. A device used to route
information to the correct place
on the internet.
DNS
How can we create a model of the Internet?
http://www.bbc.co.uk/guides/z3tbgk7#z9yk87h
How will you represent a model of the Internet for
your family to understand what happens?
Understanding the Internet
I can describe different parts of the Internet. (yr 5)
I can tell you the Internet services I need for
different purposes. (yr 6)
I can describe how information is transported on
the Internet. (yr 6)
Find an IP address
http://en.dnstools.ch/visual-traceroute.html
Client
Server
Client
http://www.yougetsignal.com/tools/visual-tracert/
Router
DNS
Who controls the Internet?
Fourteen Crypto officers or keyholders have a
traditional metal key to a safety deposit box, which in
turn contains a smartcard, which in turn activates a
machine that creates a new master key.
Four times a year a ceremony is
held to ‘change the password to
the Internet’ - the key which
maintains the DNS address book.
Seven back-up keyholders with smartcards that
contain a fragment of code needed to build
a replacement key-generating machine. Once a year,
these shadow holders send the organisation that runs
the system – the Internet Corporation for Assigned
Names and Numbers (Icann) – a photograph of
themselves with that day's newspaper and their key,
to verify that all is well.
Who controls your device?
MIT Technology review