Networking &
The Internet
Data Flow
The OSI Model
Physical
Please
Application
All
Data
Do
Presentation
People
Network
Not
Session
Seem
Transport
Throw
Transport
To
Session
Sausage
Network
Need
Presentation
Pizza
Data
Data
Application
Away
Presentation
Processing
The OSI Model

What is an IP address?

What does IP stand for?

What is a MAC address?

Why would you use a static IP address?

What does www.google.com refer to?
IP Addresses
IP Addresses work at the Network
Layer of the OSI model
To make it easier for us humans to
remember, IP addresses are
normally expressed in decimal
format as a "dotted decimal
number“ like this:
216.27.61.137
The OSI Model
IP Addresses are in fact saved in
binary. So this address:
216.27.61.137
Actually is read as this:
11011000.00011011.00111101.100
01001
The OSI Model
IP Addresses are 32 bit numbers.
Why? Because they are made up of
4 x 8bit binary numbers = 32
Each digit = 1 ‘bit’ of memory
This means that worldwide there are
a possible 4,294,967,296 IP
addresses
The OSI Model
However, within IP addresses there
are certain reserved numbers.
The first number or ‘octet’ (eight
bits) shows the type of network the
IP belongs to:
001 – 126 are Class A Addresses
Class A are large networks
consisting of many Ips
Up To
16,777,214
Possible IPs
The OSI Model
Class A IPs are stored as:
Network
Node
127.
0.0.1
128 – 191 are Class B Addresses
Class B are medium networks
consisting of a large number of IPs
Class B IPs are stored as:
Network
Node
127.0.
0.1
Up To 65,534
Possible IPs
The OSI Model
192 - 223 are Class C Addresses
Class C are small networks
consisting of several IPs
Class C IPs are stored as:
Network
Node
127.0.0.
1
Up To
254
Possible IPs
The OSI Model
Some IPs are ‘reserved’
Home, or Loopback: 127.0.0.1
Broadcast Address: 255.255.255.255
The OSI Model
Within Networks, IPs are Subnetted to
allow IPs to be assigned within the
network.
In your Internet Browser go to:
www.whatismyip.com
What information can you find about
the network you are on?
The OSI Model
What is the Purpose of Subnetting?
Discuss your findings in a short essay
format (more than a page, less than
five)
Essay format: Intro, discussion,
conclusion, SOURCES!
Homework – Due in next Friday