A presentation on the Internet, Packet Switching, IP Addresses and Routers

1. What is the Internet and what are packets, routers and IP addresses?
Find out more in this presentation.

2. What is the Internet?
• The Internet is a global network that
connects billions of computers around the
world and is like a postal service where
data can be sent to other computers.
• However, the World Wide Web is not the
same thing. The WWW is a network of
websites being linked together using
hyperlinks.
• It has become a necessity in today’s
society with the Internet and World Wide
Web being used for education, business,
shopping, connecting with other people
and pleasure. In 2012, almost 1/3 of the
world’s population had access to the
Internet.
• The Internet was invented in 1969 by the
US Department of Defence to allow
soldiers to connect with each other in
emergencies.

3. IP Addresses
• An IP address stands for Internet Protocol
Address and is a unique set of numbers
that identifies a computer, web site or
server.
• There are 2 versions of IP addresses: IPv4
and IPv6. The most common is the IPv4
and uses 32 binary digits, split in into
octets and is usually 4 numbers separated
by dots, for example 2.30.107.55.
• An IP address is like an address to a door
so other computers can send data to the
right address.
• The are static and dynamic IP addresses.
Static are permanent and are good if you
want to make it easy for other computers
to locate you but dynamic are more
common and are temporary and are given
by your Internet Service Provider.

4. Domain Names
• A domain name represents one or more IP
addresses and is usually the name of the
website, for example google.com or
microsoft.com.
• Every computer or server has a Domain
Name System (DNS) to translate Domain
Names into IP Addresses and vice versa.
• We have domain names because it is easier
to remember rather than a group of numbers.
• The link between domain names and IP
addresses is that a domain name is what
people type to get to an web address and an
IP address is the name of the web address.
• Every domain name has a suffix which tells
us which Top Level Domain it belongs to.
Some are countries such as co.uk or .es.
• Others include .org for an organisation or
.edu for Higher Education.

5. What is Packet Switching? 1
• A data packet, or network packet, is data
which has been split up into packets
which are then sent to a destination
computer. It contains the data itself,
where it is going to and where it has
come from.
• Packet Switching is splitting data up into
small packets and helping it arrive at its
destination.
• When it leaves a computer, it goes
through the network and will head off in
different directions, taking the least busy
route with the help of a Router.
• During the course of its journey, it will go
through many routers, often in many
different countries. Also, if one route is
broken, it is automatically routed onto
another route.

6. What is Packet Switching? 2
• When the packets reach their destination, they
are put back together in the correct order. This
is made easier because when the packets
were being split up, they were each given a
number.
• If a packet doesn’t reach the destination, a
message is sent back to the sender for a
replacement packet.
• However, some packets can get lost on its
journey and will jump from router to router and
to make sure it doesn’t disrupt the network,
there is a ‘Hop’ Count to each packet so it can
only jump from router to router a set number of
times before it is deleted.
• The advantage of packet switching is that it is
very efficient and one broken route won’t affect
the entire network.
• However, the disadvantage of a packet is that
small data items aren’t good and it takes time
for the packet switching to happen.

7. Routers
• A router is a device that transfers data
from one network to another network and
to its destination using the quickest route.
• A router is found at a gateway where two
or more networks connect.
• A router has a micro-computer inside that
contains a list of all the networks it is
connected to and how busy the network
is.
• When a data packet reaches a router, it
will find out where the packet needs to go,
looks up all the networks available to go
to that destination, checks how busy all
the available networks are and send the
packet along the fastest network.
• Also, routers are needed for a computer
to connect to the Internet so that it can
send and receive packets.

8. Routers in action
To track which routers and how many hops it took, type ‘cmd’ into the
‘Search Programs and Files’ section. This is the trace route for
www.amazon.com and you can see on hop 8 and 9, the router was in
London and on hops 10,11 and 12, the router was in New York. It took 30
hops in total.

9. References and Sources
• What is the Internet?
• http://www.bbc.co.uk/webwise/guides/what-is-the-internet
• http://www.gcflearnfree.org/internet101/1 - This websites has lots of information on what the Internet is in a simple and
understandable way so that’s why I think this is a good website.
• IP Addresses
• http://whatismyipaddress.com/ip-address
• http://computer.howstuffworks.com/internet/basics/question549.htm - This website goes into detail in its information but
presents it in an understandable way.
• Domain Names
• http://www.webopedia.com/TERM/D/domain_name.html - Easy to understand definition of Domain Names
• http://www.cyberindian.com/domain-registration/article.php?article_id=72
• http://en.wikipedia.org/wiki/List_of_Internet_top-level_domains - Includes a long list of different TLDs
• What is Packet Switching?
• http://www.teach-ict.com/glossary/D/data_packet.htm
• http://www.teach-ict.com/technology_explained/packet_switching/packet_switching.html - This website goes into a lot
of detail but in a child-friendly way so school children can understand what has been written.
• Routers and Routers in Action
• http://www.webopedia.com/TERM/R/router.html
• http://www.teach-ict.com/gcse_new/networks/hardware/miniweb/pg4.htm# - This is the same website as the packet
switching and is really good because it is easy to understand.
• http://www.wikihow.com/Traceroute