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CCNA 1

Module 1:Introduction

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1.1 Connecting to the Internet

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Requirements for Internet connection

• Physical -Network Interface Card (NIC)• Logical -protocol (TCP/IP)• Application -interpret data and display them (Web browser)

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Network Interface Card NIC

•Also called a LAN adapter•It is a printed circuit board that provides network communication •It plugs into a motherboard & provides a port for network connection

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Things to consider when you select a NIC

•The type of network (Ethernet, token ring, FDDI,….)

•Type of media (twisted-pair, coaxial, fiber-optic cable)

•Type of system bus (PCI and ISA)

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Here are some possible situations that may require you to install a NIC.

•Adding a NIC to a computer that does not already have one

•Replacing a bad or damaged NIC

•Upgrading from a 10 Mbps card to a 10/100 Mbps card

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PC Components Versus Laptop Components

The main difference is that components in a laptop are smaller – the expansion slots become PCMCIA slots, where NICs, modems, hard drives and other useful devices can be inserted into the slots along the perimeter (usually the size of a thick credit card).

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TCP/IP description and Configuration

After you have set up the PC hardware you must configure its software.

•Select the NIC•Set the correct IP address•Adjust the display (if necessary)•Install and set up the browser•Perform a few other task (if necessary)

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Protocols•A set of rules and conventions that govern how devices on a network exchange information.•An agreed-upon format for transmitting data between two devices. The protocol determines:

the type of error checking to be used data compression method, if any how the sending device will indicate that it has finished sending a message how the receiving device will indicate that it has received a message

•In order for computers on a network to directly communicate with each other they must have a common protocol.

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Connecting to a Network & Configuring TCP/IP Settings

•In order for a PC to be part of a network, you must connect it to the network and configure a protocol for it to communicate with the rest of the network.

•To configure the TCP/IP settings, click on the Start button and select Settings. Then go to the Control Panel and double click on the Network icon.

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Configuring TCP/IP

To begin, double click on the TCP/IP icon or click on it once and then click on Properties

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Configuring TCP/IP

Click on the IP Address tab.

This will allow you to enter the IP Address & Subnet Mask for the workstation.

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Configuring TCP/IP

You may need to set a Gateway also, if so, click on the Gateway tab.

Type in the new gateway and click Add.

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Why Network Computers?

•To avoid duplication of equipment and resources•To communicate efficiently

Networking Computers

Networking a variety of networks together was difficult in the mid 1980’s, because emerging network technologies used different hardware and software specifications.

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Testing connectivity with ping

• ping 127.0.0.1• ping IP address of host computer • ping default-gateway IP address • ping remote destination IP address

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Web browser and Plug-ins

A web browser performs the following functions: • Contacts a web server • Requests information • Receives information • Displays the results on the screenPlug-ins• Flash – multimedia files• QuickTime – video files• Real player – audio files

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Troubleshooting

In trouble shooting a computer it is important to look at the following:•Hardware•Software•Network connection•User

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Binary Digits (bits)

•Computers can only understand and process data that is in a binary format (0s and 1s).•Bits are either 0s or 1s.•Bits are represented in a computer by the presence or absence of electrical patterns.

binary 0 might be represented by 0 volts of electricity binary 1 might be represented by +5 volts of electricity

•A group of 8 bits equals 1 byte

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1.2 Network Math

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Numbering Systems

•Decimal (base 10)uses 10 symbols0, 1, 2, 3, 4, 5, 6, 7, 8, 9

•Binary (base 2)uses 2 symbols0, 1

•Hexadecimal (base 16)uses 16 symbols0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F

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Numbering Systems

10^4 10^3 10^2 10^1 10^0 Decimal10,000 1,000 100 10 1

4 2 6 426

Base 10

2^7 2^6 2^5 2^4 2^3 2^2 2^1 2^0 Decimal128 64 32 16 8 4 2 1

1 0 0 1 1 19

Base 2

16^4 16^3 16^2 16^1 16^0 Decimal65,536 4,096 256 16 1

1 2 A 298

Base 16

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Binary CountingDecimal Binary Decimal Binary01101110010111011110001001101010111100

110111101111100001000110010100111010010101101101011111000

0123456789101112

13141516171819202122232425 11001

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Converting decimal numbers to 8-bit binary numberMethod 1

Convert the decimal number 192 into a binary number.

192/2 = 96 with a remainder of 096/2 = 48 with a remainder of 048/2 = 24 with a remainder of 024/2 = 12 with a remainder of 012/2 = 6 with a remainder of 06/2 = 3 with a remainder of 03/2 = 1 with a remainder of 11/2 = 0 with a remainder of 1Write down all the remainders, backwards, and you have the binary number 11000000.

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Converting decimal numbers to 8-bit binary numberMethod 1

Convert the decimal number 235 into a binary number.

235/2 = 117 with a remainder of 1117/2 = 58 with a remainder of 158/2 = 29 with a remainder of 029/2 = 14 with a remainder of 114/2 = 7 with a remainder of 07/2 = 3 with a remainder of 13/2 = 1 with a remainder of 11/2 = 0 with a remainder of 1Write down all the remainders, backwards, and you have the binary number 11101011.

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Converting decimal numbers to 8-bit binary numberMethod 2

Convert the decimal number 192 into a binary number. First find the largest number that is a power of 2 that you can subtract from the original number. Repeat the process until there is nothing left to subtract.192-128 = 64 128’s used 1 64-64 = 0 64’s used 1 32’s used 0 16’s used 0 8’s used 0 4’s used 0 2’s used 0 1’s used 0Write down the 0s & 1s from top to bottom, and you have the binary number 11000000.

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Converting decimal numbers to 8-bit binary numberMethod 2

Convert the decimal number 213 into a binary number. First find the largest number that is a power of 2 that you can subtract from the original number. Repeat the process until there is nothing left to subtract.213-128 = 85 128’s used 1 85-64 = 21 64’s used 1*(32 cannot be subtracted from 21) 32’s used 0 21-16 = 5 16’s used 1*(8 cannot be subtracted from 5) 8’s used 0 5-4 = 1 4’s used 1*(2 cannot be subtracted from 1) 2’s used 0 1-1 = 0 1’s used 1Write down the 0s & 1s from top to bottom, and you have the binary number 11010101.

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Converting 8-bit binary numbers to decimal numberMethod 1

27 26 25 24 23 22 21 20

128 64 32 16 8 4 2 1 1 0 1 1 0 1 0 1

From right to left, write the values of the powers of 2 above each binary number. Then add up the values where a 1 exist.

128 + 32 + 16 + 4 + 1 = 181

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Converting 8-bit binary numbers to decimal numberMethod 1

27 26 25 24 23 22 21 20

128 64 32 16 8 4 2 1 1 1 0 1 1 1 0 0

From right to left, write the values of the powers of 2 above each binary number. Then add up the values where a 1 exist.

128 + 64 + 16 + 8 + 4 = 220

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Converting 8-bit binary numbers to decimal numberMethod 2

•Start from the left with the first 1 in the binary number. Write down a 1 below it.

•Then look at the next number to the right• if it is a 0, double the previous number and write it down• if it is a 1, double the previous number and add 1 to it, then write it down

•Continue this until you reach the last 0 or 1 in the binary number.

•The last number you write down is the decimal equivalent of the binary number.

128 64 32 16 8 4 2 1 1 1 0 1

Binary place value

Binary number

Conversion 1 3 6 13

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Converting 8-bit binary numbers to decimal numberMethod 2

128 64 32 16 8 4 2 1 1 1 0 1 0

Binary place value

Binary number

Conversion

128 64 32 16 8 4 2 1 1 0 0 1 1 1

Binary place value

Binary number

Conversion

128 64 32 16 8 4 2 1 1 1 1 1 0 1 1

Binary place value

Binary number

Conversion

1 3 6 13 26

2 4 9 19 391

7 15 30 61 12331

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Four-octet dotted decimal representation of 32-bit binary numbers

Eg. 172.17.0.254198.165.124.12

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Hexidecimal (Hex)•Hexadecimal is a Base 16 numbering system that is used to represent MAC addresses.

•It is referred to as Base 16 because it uses sixteen symbols; combinations of these symbols can then represent all possible numbers. Since there are only 10 symbols that represent digits (0, 1, 2, 3, 4, 5, 6, 7, 8, 9), and the Base 16 requires 6 more symbols, the extra symbols are the letters A, B, C, D, E, and F.

•The position of each symbol, or digit, in a hex number represents the base number 16 raised to a power, or exponent, based on its position.

Know these

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Hex to Decimal ConversionTo convert a hex number to a decimal number, multiply the each hex number by the its place value. Then add all the values together.

Given the hex number A 3 163 162 161 160

4096 256 16 1

A 3

A X 16 = 160

3 X 1 = 3

160 + 3 = 163

So A316 = 16310

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Hex to Decimal ConversionTo convert a hex number to a decimal number, multiply each hex number by the its place value. Then add all the values together.

Given the hex number B A D 163 162 161 160

4096 256 16 1

B A D

B X 256 = 2816

A X 16 = 160

D X 1 = 13

2816 + 160 + 13 = 2989

So BAD16 = 298910

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Hex to Binary ConversionTo convert a hex number to a binary number, each hex bit represents 4 binary digits

Given the hex number A 3A is the decimal number 10

10 in binary is 1 0 1 0

8 4 2 1 (binary number places - 4 bits)

1 0 1 0

3 is the decimal number 3

3 in binary is 0 0 1 1

8 4 2 1 (binary number places - 4 bits)

0 0 1 1

hex A 3 = 1 0 1 0 0 0 1 1 in binary

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IP Addresses and Network Mask• Use 32-bit binary addresses for Internet Protocol (IP) addresses. • some of the bits on the left side of the 32-bit IP number represent

a network. • bits left over in the 32-bit IP address identify a particular computer

on the network.

To inform a computer how the 32-bit IP address has been split, a second 32-bit number called a subnetwork mask is used.

11111111000000000000000000000000 written in dotted decimal as 255.0.0.0 or 11111111111111110000000000000000 written in dotted decimal as 255.255.0.0

Converting the IP address 10.34.23.134 to binary would result in: 00001010.00100010.00010111.10000110

Performing a Boolean AND of the IP address 10.34.23.134 and the subnet mask 255.0.0.0 produces the network address of  this host:

00001010.00100010.00010111.1000011011111111.00000000.00000000.0000000000001010.00000000.00000000.00000000