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 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 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 This address always indicates the local machine The Ping command send a small packet of information using TCP/IP So the command “Ping “ 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 File Transfer Protocol (FTP) File Sharing Multi-Player 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 Base 10  The number of digits in a sytem can be discovered by taking 1 from the base so  Base 10 = = 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  Base 2 = Binary = = 1 therefore the digits are 0 and 1  Base 8 = Octal = = 7 therefore the digits are

Decimal 10 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

Decimal (10 3 )100 (10 2 )10 (10 1 )Units (10 0 )-LSD Count = 10

Decimal 10 When the maximum digit value is reached, we reset the digit and Increment the next column 1000 (10 3 )100 (10 2 )10 (10 1 )Units (10 0 ) :::::::: Reset & Inc. :::::::: ::::::::

Binary 2 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

Binary 2 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 =

Binary 2 8 (2 3 )4 (2 2 )2 (2 1 )Units (2 0 ) Count = 2

Hexadecimal 16 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

Hexadecimal 16 Decimal256 (16 2 )16 (16 1 )Units (16 0 ) :::::::: A 1100B 1200C 1300D 1400E Count = F Reset & Inc

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 =

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 column 122- repeat this process until you reach zero = U

Binary to Decimal U 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 Therefore =

Binary to Hex If we take the binary number , the first step is to split it into groups of 4 bits from the LSB, then calculate Each group of U =10 10=A =15 15 = F U 1 0 Answer = FA 16 =

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 15E Step U U Step Step

Decimal Binary Hex 10Units16842Units16Units A B C D E F Conversion Chart