Download Network Connections & Number System

Introduction to IT and
Communications Technology
Network Connections
& Number Systems
Justin Champion
Content

What this we will look at






Understand the physical connections needed for
a computer to connect to a network
Recognize the components of a computer
Install and troubleshoot NICs and modems
Configure the set of protocols needed for
Internet connection
Use basic procedures to test an Internet
connection
Demonstrate a basic ability to use Web
browsers and plug-ins
Requirements for Internet connection

What is needed to connect to ANY network?
 Physical Connection



Logical Connection


Ethernet
ATM
TCP/IP – is commonly used
Applications to display the information


Web browser
Email client
Physical Connection

Physical
 This is the connection used to transfer
the electrical signal
 Technology used depends on the
requirements of the machine
 PCI
Ethernet Card
 PCMCIA Ethernet Card
 USB Ethernet adapter
 Modem
Physical Connection
PC card modem & 56k modem
USB 10/100 network adapter
Dialup networking

Early Networking

1960s


1970s


As computers got more sophisticated increasing in the amount
of data to be transferred
1990s


BBS allowed the posting of messages on a bulletin board
1980s


Modems used to connect ‘dumb’ terminals to a server
Modem increased speed to 56 Kilo bits per second (Kbps)
2000

High speed data transfer is required, for the increasing use of the
Internet with variety of usage
Logical Connection

Once the physical / hardware connection is
made
A logical connection is then used at the
computer
 These connections are configured and are
based in software, within the Operating Systems
(OS)


The most common of these is the TCP/IP

Transport Control Protocol (TCP)/ Internet Protocol (IP)
Logical Connection

Configuration
Within the OS the logical connection needs to be
configured
 Providing information about the specific network
you are going to connect to


This could be
The Internet and communicating globally
 Communicating locally with the machine on the other side of
the room

Ping loopback address

The configuration can be tested quickly to see the
correct software is installed


However this does not tell you that the machine is
correctly installed to work on the network
This is done using a Ping Loopback address




This is a unique and reserved IP address of 127.0.0.1
This address always indicates the local machine
The Ping command send a small packet of information using
TCP/IP
So the command “Ping 127.0.0.1“ send a small packet of
information to the computer which issued the command
Ping loopback address

Demo using a command prompt
Once connected

Once the network is configured


The sharing of information can begin
The most commonly used will be connecting to the
Internet for

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World Wide Web (WWW) browsing
Email
File Transfer Protocol (FTP)
File Sharing
Multi-Player Games


www.free-games.com.au/Free_Online_Multiplayer_Games/
And much more
Problems with a connection

If your loop back address did not work
There has been a problem with the configuration
 You then need to prove yourself as a network
professional


You can try and fix the problem via logic and the most
obvious solutions
This can sometimes be very quick
 More often than not though this will lead to additional
unnecessary work

Troubleshooting process

By following a plan this work can be greatly
reduced
Define the problem
 Gather the facts
 Consider the possibility
 Create an action plan
 Implement the plan
 Document the results
 Introduce problems and troubleshoot

Success


This should then give you a successful
network which you can use
Over the next few tutorials

Specific details about the networks will be
discussed
Physical connections and considerations
 Logical connections and how to configure them

Number Systems

In every day life we use the numbers 0 to 9



Something costs 99 pence
You will be paid £5.52 per hour as wages
This number system is referred to as Base10



The number of digits in a sytem can be
discovered by taking 1 from the base so
Base10 = 10 -1 = 9 digits
Which matches with what we know from every
day usage
Number Systems

There are other number systems



We will shortly go through why we need these
additional systems
Base2 = Binary = 2 - 1 = 1 therefore the digits
are 0 and 1
Base8 = Octal = 8 - 1 = 7 therefore the digits are
01234567
Decimal10

To then build up larger numbers the digits are
combined together

The digits on the right hand side are the least
significant digits




These are digits which store the smallest numbers
Look at the value 909
If the least significant value was reset to 0, only 9 values would
be lost
Increasing by the power of the base as they move left,
which is referred to as the most significant digits

If this was reset to 0 then 900 values would be lost
Decimal10
1000 (103)
100 (102)
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
10 (101)
0
0
0
0
0
0
0
0
0
0
Units (100)-LSD
0
1
2
3
4
5
6
7
8
9
Count = 10
Decimal10
When the maximum digit value is reached, we reset the digit and
Increment the next column
1000 (103)
100 (102)
0
0
:
0
0
:
0
:
0
0
0
0
:
0
0
:
0
:
0
1
10 (101)
0
0
:
0
1
:
2
:
9
0
Units (100)
0
1
:
9
0
:
9
:
9
0
Reset & Inc.
Binary2

As discussed earlier there are other number
systems

These number systems are needed for specific reasons

Binary




Used in computers and with network addresses
Binary can be used to represent switches, 1 and 0 and on and off, true
and false
This makes this number system ideal to be used within computers
Hexadecimal



This number system can be used to represent larger binary values
Such as those found in network addresses or memory due to the large
numbers involved
The most common place to find these is the hardware MAC addresses

The MAC address is a unique identifier for a Ethernet
network card, based on a 48 bit value
Binary2



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Binary has a base of 2, I.e. a count of 2
Therefore the maximum single digit is base–1,
2-1 = 1
Binary can only have the value 0 or 1
These two vales relate as follows:


Binary 1 is taken as logic 1, +Ve
Binary 0 is taken as logic 0, 0V

Binary is often used in IP addressing
E.g if we look at a Class A address

124.95.44.15 = 01111100.01011111.00101100.00001111

Binary2
8 (23)
4 (22)
2 (21)
0
0
0
0
0
0
0
0
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
0
0
1
1
0
0
Units (20)
0
1
0
1
0
1
0
1
0
1
Count = 2
Hexadecimal16


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
Hex has a base of 16 (count of 16).
Therefore the maximum single digit is base
– 1, 16-1 = 15
However 15 is not a single digit, so we need
to find an alternative
Once we reach the value 9 we use letters
(we will see this on the next slide)
Hex is often used in MAC addressing and
memory addressing
E.g. FE:FD:F9:44:45:66
Hexadecimal16
Decimal
0
1
:
8
9
10
11
12
13
14
15
16
17
256 (162)
0
0
:
0
0
0
0
0
0
0
0
0
0
16 (161)
0
0
:
0
0
0
0
0
0
0
0
1
1
Units (160)
0
1
:
8
9
Count = 16
A
B
C
D
E
F
0 Reset & Inc.
1
Conversion of number systems

Conversion between systems



Just because a number is in binary does not
mean it will remain so
It may be more convenient to change the
number system to represent the same value
For example

The binary which represents an IP addresses
converted to a format that people can easily read
11110001.11010010.01101110.00011011 = 241.210.110.27
Conversion of number systems

The conversion of numbers can take
place with repeated Multiplication,
division, addition and subtraction


Although computers find this easy, humans
rarely do!
The easiest way to convert between system
is to convert the numbers into binary first
Decimal to Binary
128 64 32 16 8 4 2 U
25010 =
1 1 1 1 1 0 1 0
250- Try and subtract the largest binary position
128 in this case 128, if it can be done put a 1 in the column
122- repeat this process until you reach zero
64
5832
2616
108
22
0
Binary to Decimal
This is far simpler this decimal to binary, take your binary
And place the column heading over the top. Where there
Is a one add the column values together
27 26 25 24 23 22 21 20
128 64 32 16 8 4 2 U
1
1 0
0 1 1 0 1
Therefore 128+64+8+4+1 = 20510
Binary to Hex
If we take the binary number 11111010, the first step is
to split it into groups of 4 bits from the LSB, then calculate
Each group of 4
842U
1111
8+4+2+1=15
15 = F
842U
1010
8+2=10
10=A
Answer = FA16 = 25010
Hex to Binary
This is really the reverse of what we have just done we
take each Hex digit separately and convert it into 4 bit
Binary. Push all the bits together to form 1 Binary number
We will use the Hex number 5E
Step 1
Step 2
Step 3
Step 4
5
842U
0101
E
842U
1 110
010111102
Conversion Chart
Decimal
10
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
Units
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
Binary
16
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
8
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
4
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
Hex
2
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
Units
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
16
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
Units
0
1
2
3
4
5
6
7
8
9
A
B
C
D
E
F
0