Introduction to IT and Communications Technology

Justin Champion

Network Connections & Number Systems

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

Ethernet ATM

Logical Connection TCP/IP – is commonly used

Applications to display the information Web browser Email client

Physical Connection

PhysicalThis is the connection used to transfer

the electrical signalTechnology used depends on the

requirements of the machinePCI Ethernet CardPCMCIA Ethernet CardUSB Ethernet adapterModem

Physical Connection

PC card modem & 56k modem

USB 10/100 network adapter

Dialup networking

Early Networking 1960s

Modems used to connect ‘dumb’ terminals to a server 1970s

BBS allowed the posting of messages on a bulletin board 1980s

As computers got more sophisticated increasing in the amount of data to be transferred

1990s 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 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) 10 (101) Units (100)-LSD

0 0 0 00 0 0 10 0 0 20 0 0 30 0 0 40 0 0 50 0 0 60 0 0 70 0 0 80 0 0 9

Count = 10

Decimal10

When the maximum digit value is reached, we reset the digit andIncrement the next column

1000 (103) 100 (102) 10 (101) Units (100)

0 0 0 00 0 0 1: : : :0 0 0 90 0 1 0 Reset & Inc.: : : :0 0 2 9: : : :0 0 9 90 1 0 0

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

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) Units (20)

0 0 0 00 0 0 10 0 1 00 0 1 10 1 0 00 1 0 10 1 1 00 1 1 11 0 0 01 0 0 1

Count = 2

Hexadecimal16

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 256 (162) 16 (161) Units (160)

0 0 0 01 0 0 1: : : :8 0 0 89 0 0 910 0 0 A11 0 0 B12 0 0 C13 0 0 D14 0 0 E

Count = 16

15 0 0 F16 0 1 0 Reset & Inc.17 0 1 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

250- Try and subtract the largest binary position 128 in this case 128, if it can be done put a 1 in the column122- repeat this process until you reach zero 64 58- 32 26- 16 10-

25010 =

128 64 32 16 8 4 2 U

11 1 11 001

8 2-20

Binary to Decimal

27 26 25 24 23 22 21 20

128 64 32 16 8 4 2 U

This is far simpler this decimal to binary, take your binaryAnd place the column heading over the top. Where thereIs a one add the column values together

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 isto split it into groups of 4 bits from the LSB, then calculateEach group of 4

8 4 2 U1 1 1 1

8+2=1010=A

8+4+2+1=15

15 = F

8 4 2 U1 0 1 0

Answer = FA16 = 25010

Hex to Binary

This is really the reverse of what we have just done wetake each Hex digit separately and convert it into 4 bitBinary. Push all the bits together to form 1 Binary numberWe will use the Hex number 5E

Step 1 5 EStep 2 8 4 2 U 8 4 2 UStep 3 0 1 0 1 1 1 1 0

Step 4 010111102

Decimal Binary Hex

10 Units 16 8 4 2 Units 16 Units0 0 0 0 0 0 0 0 00 1 0 0 0 0 1 0 10 2 0 0 0 1 0 0 20 3 0 0 0 1 1 0 30 4 0 0 1 0 0 0 40 5 0 0 1 0 1 0 50 6 0 0 1 1 0 0 60 7 0 0 1 1 1 0 70 8 0 1 0 0 0 0 80 9 0 1 0 0 1 0 91 0 0 1 0 1 0 0 A1 1 0 1 0 1 1 0 B1 2 0 1 1 0 0 0 C1 3 0 1 1 0 1 0 D1 4 0 1 1 1 0 0 E1 5 0 1 1 1 1 0 F1 6 1 0 0 0 0 1 0

Conversion Chart