Made for Brindabella Christian College

1. Network Protocols

2. What is the internet?
The internet is a global network of computers that any
computer can join. It is a WAN - which is a series of
connected LANs.
Data packets are sent between computers using protocols
that manage how data is sent and received. The internet
also uses different models - such as the client-server
model and the P2P model - to connect computers in
different ways. The internet is leading to more and more
people using cloud computing to store files and use web
applications online.

3. Services available over the internet
• Web pages – HTML documents that present images, sound
and text accessed through a web browser
• Web applications - web software accessed through a
browser
• Native apps - applications developed for specific devices
(such as smartphones) and accessed without the need for
a browser

4. Services available over the internet
• Email
• File sharing
• Voice calls
• Streaming audio and video

5. Connecting to the internet
To connect a computer or a device to the internet, you
need:
• an ISP (Internet Service Providor)
• a modem or router (wired or wireless)
• a web browser or app
• a connection to the network (through a copper wire or a
fibre optic cable)

7. Fibre optics
Fibre optic cabling is made from glass that
becomes very flexible when it is thin. Light is
passed through the cable using a transmitter.
Light travels quickly through the light-
reflecting internal wall of the cable.
The transmitter in the router sends light
pulses representing binary code. When the
data is received, it is decoded back to its
binary form and the computer displays the
message.

8. Copper cable
Copper cable uses electrical signals to pass
data between networks instead of light. It is
much slower than fibre optics and the signal
cannot travel as far.
Copper cable is a much cheaper alternative to
fibre optics.

9. Protocols
The internet is similar to a road network in that it has rules (protocols)
that you need to follow and only a certain number of vehicles (data)
can get through at a time (bandwidth). If too many vehicles try to go
down the same road you get congestion (reduced bandwidth).
When two devices send messages to
each other it is called handshaking - the
client requests access, the server grants
it, and the protocols are agreed. Once
the handshaking process is complete,
the data transfer can begin.

10. Protocols
Protocols establish how two computers send and receive a message. Data
packets travel between source and destination from one router to the next.
The process of exchanging data packets is known as packet switching.
Protocols manage key points about a message:
• speed of transmission
• size of the message
• error checking
• deciding if the transmission is synchronous (regular) or asynchronous
(irregular)

11. TCP/IP
(transmission control protocol/internet protocol)
TCP/IP (also known as the internet protocol suite) is the set of
protocols used over the internet. It organises how data packets are
communicated and makes sure packets have the following information:
• source - which computer the message came from
• destination - where the message should go
• packet sequence - the order the message data should be re-assembled
• data - the data of the message
• error check - the check to see that the message has been sent
correctly

12. Internet protocols
Within TCP/IP there are several key protocols. These include the
following.
IP address
• Every device on the internet has a unique IP address. The IP
address is included in a data packet. The address is broken down
into four 8-bit numbers (each is called an octet). Each octet can
represent a number between 0 and 255 and is separated by a full
stop, eg 192.168.0.12.

13. Internet protocols
FTP (File Transfer Protocol)
• FTP is used to transfer large files. It is often used for organising
files on a web server for a website. You can have private access
to an area on an FTP server where you can upload your files. You
can then give another user access to download the documents
that you have shared.

14. Internet protocols
HTTP (Hypertext Transfer Protocol)
• HTTP transfers web pages from web servers to the client. All web
page addresses start with http. An https address is a secure web
address which has been encrypted. An https address is used for
sites holding bank details and secure information.

15. Internet protocols
SMTP (Simple Mail Transfer Protocol) and
POP3 (Post Office Protocol)
• Email uses these protocols to communicate with mail servers.
SMTP is used to send the email; POP is used to receive email.
VOIP (Voice Over Internet Protocol)
• VOIP is a set of protocols that enables people to have voice
conversations over the internet.

16. Web Addresses
Every website address has a URL (Uniform Resource Locator) with
an equivalent IP address. A web address contains (running from
left to right):
1. http(s)
2. the domain name - the name of the website
3. an area within that website – like a folder or directory
4. the web page name – the actual page that you are viewing

17. Web Addresses
For example: http://www.bcc.act.edu.au/lyneham/why-choose-
bcc/message-from-principal/vision-statement
1. http is the protocol
2. www.bcc.act.edu.au is the domain name
3. /lyneham/why-choose-bcc/message-from-principal/ is the
folder structure leading to where the web page is located
4. vision-statement is the requested web page

18. Name Servers
Name servers are used to host and match website addresses to IP
addresses.
DNS (Domain Name System) is the main system over the internet
that searches the name servers.
When you type in a URL, the DNS looks up the domain name, finds
the matching IP address and sends it back.
Every website has a URL with an equivalent IP address.

20. Streaming
Streaming high-quality images, music and
video requires a lot of data. Music and
video files can both be either downloaded
as permanent files or streamed
temporarily.
A downloaded file creates a file you can
store permanently. Streamed files are not
stored permanently. Streaming allows data
to be used immediately but the whole file
is not downloaded. Popular streaming sites
include Spotify and YouTube.

21. Buffering
A buffer is a temporary storage space where data can be held and
processed. The buffer holds the data that is required to listen to or
watch the media. As data for a file is downloaded it is held in the
buffer temporarily. As soon as enough data is in the buffer the file
will start playing.
When you see the warning sign
'buffering' this means that the
client is waiting for more data
from the server. The buffer will
be smaller if the computer is on
a faster network.

22. End of Presentation