Determine a node’s IP Network Address Gina Minks EME5603 Fall 2008 Final Project For EMC...

Determine a node’s IP Network Address

Gina MinksEME5603 Fall 2008 Final ProjectFor EMC Employees

IntroductionIn a large IP environment, routers are used to break up large

networks into subnetworks.

This diagram shows a router breaking a network into three subnets; one for engineering, one for QA, an one for sales.

Each node in a network is identified by an IP address and a subnet mask. These two pieces of information can be used to identify on which subnet the node resides.

Being able to identify the network information helps make routing between networks efficient.

EngineeringSales

QA

Internet

Internet

Why take this module?

By the end of this module, you will be able to take any IP Address and Subnet mask, and using only a pencil and piece of paper determine the network address for that pair.

If you work with any of the Network Management/Configuration products you will need to be familiar with basic network troubleshooting skills.

If you work with any products that are connected to an IP network, you probably need to know how to troubleshoot that IP connection.

Objectives

• Given an IP Address, convert the IP address from Decimal to Binary

• Given a Subnet Mask, convert the Subnet Mask from Decimal to Binary

• Perform a Boolean AND operation on the Binary IP Address and Binary Subnet Mask

• Given the result of a Boolean operation on an IP Address and Subnet Mask, convert the binary operation results to decimal format

• Write the Network Address for the given IP Address and Subnet Mask in dotted decimal notation

These are the steps used to find the network address from the IP Address and the Subnet Mask.

We’ll go over each of these steps in detail in upcoming pages.

Review of terms

Before we get started, let’s go over a few terms you will need to know to complete this module.

1. Octet: 8 consecutive bits, or one byte. IP addresses have 4 octets

2. MSD: Most Significant DigitThis is the left most digit, or the digit with the greatest value in the number

3. LSD: Least Significant DigitThis is the right-most digit, or the digit with the least value in the number

4. Dotted Decimal Notation:IP addresses are written in decimal format so that they are easier for humans to read. The numbers are the decimal representation of the binary octets. Each octet is separated by a decimal.

Now that we’ve reviewed the terminology, let’s get started!

192.168.1.1011

2

1

2

3

3

Determining the Network Address

Suppose we have the following information about a node on the network:

IP Address 192.168.1.101

Subnet Mask 255.255.255.0

How do you figure out the network on which the node resides?

Engineering Sales

QA

These are all of the steps required to determine the network ID of an IP Address and Subnet Mask:

• Separate the IP address & Subnet Mask into octets

• Convert each octet from decimal to binary

• Perform an AND on the IP address & Subnet Mask

• convert the result of step three from binary to decimal

• Write the converted number in dotted decimal notation. This is the network IP Address: 192.168.1.1

Steps to find the network ID

Subnet Mask 255 255 255 0

IP Address 192 168 1 101

Subnet Mask 11111111 1111111 11111111 00000000

IP Address 11000000 10101000 00000001 01100101

Subnet Mask 11111111 11111111 11111111 00000000

IP Address 11000000 10101000 00000001 01100101

AND 11000000 10101000 00000001 00000000

AND 192 168 1 0

Hang in there…

We’ll go through this step by step

Don’t freak out yet!

Step 1: Separate the IP address & Subnet Mask into octets

Both the IP Address and the Subnet mask must be converted from decimal to binary. This will be easier if you work on one address and one octet at a time

For the example we’ll work through in this module, we’ll use the following node information:

IP Address: 10.127.96.219

Subnet Mask: 255.255.255.0

Network Address: ____________

Let’s start by separating the IP address into octets. Can you list the four octets of this IP Address?

10.127.96.219

Did you list the following as the octets?

• 10

• 219

• 127

• 19

Fantastic!

Each octet of the IP address and Subnet Mask must be converted from decimal format to binary format.

To make things easy at first, fill out this chart as you complete the conversion.

Separate the IP address & Subnet Mask into octets

10 127 96 219 Decimal

Binary

Step Two: Convert each octet to binary

Let’s review the steps to convert a decimal number to binary, and then you can practice performing a few conversions on your own

First, we’ll review the rules we need to follow.

Rules for converting decimal to binary

Evaluate the number, beginning with the MSB

The number is > 128 The number is = 128 The number is < 128

1. Write a 1 in the binary conversion chart column



2. Subtract 128 from the number

2. Write a 0 in each remaining conversion chart column

2. Evaluate the number with the next place value in the conversion chart

3. Evaluate the difference with the next place value in the conversion chart

3. Write each number in the conversion chart out – this is the binary number

3. Continue until the LSB has been evaluated



Examples for the 128 column

Let’s continue to evaluate the 10.127.96.219 IP address.

Start with the right-most octet (219)• 219 is MORE THAN 128• Place a 1 in the MSB column of the binary conversion chart

128 64 32 16 8 4 2 1 Place Value

1 ? Binary

128 64 32 16 8 4 2 1 Place Value

1 Binary

• Subtract 128 from 219: 228

-128 91

• Evaluate 91 with the next place value (64)• YOU TRY IT:

Do you put a 1 or a 0 in the 64 place value column?

ANSWER

128 64 32 16 8 4 2 1 Place Value

1 1 Binary

• 91 is GREATER THAN 64, so a 1 goes in the 64 place value column

• YOU TRY IT:What do you do next?

Next step --

• That’s right! Subtract 64 from 91: 91

-64 27

• And then evaluate 27 with the next place value (32).

• YOU TRY IT:What number goes in the 32 place value column?

128 64 32 16 8 4 2 1 Place Value

1 1 ? Binary

ANSWER

128 64 32 16 8 4 2 1 Place Value

1 1 0 Binary

• 27 is LESS THAN 32, so a 0 goes in the 32 place value column

• You are doing great! Keep going!


Next step --

• That’s right! Evaluate 27 with the next place value (16).


128 64 32 16 8 4 2 1 Place Value

1 1 0 ? Binary

ANSWER

128 64 32 16 8 4 2 1 Place Value

1 1 0 1 Binary

• 27 is MORE THAN 16, so a 1 goes in the 16 place value column



Next step --


-16 11

• Now evaluate 11 with the next Place Value column (8).


128 64 32 16 8 4 2 1 Place Value

1 1 0 1 ? Binary

ANSWER

128 64 32 16 8 4 2 1 Place Value

1 1 0 1 1 Binary

• 11 is MORE THAN 8, so a 1 goes in the 8 place value column



Next step --


- 8 3

• Now evaluate 3 with the next Place Value column (4).


128 64 32 16 8 4 2 1 Place Value

1 1 1 0 1 ? Binary

ANSWER

128 64 32 16 8 4 2 1 Place Value

1 1 0 1 1 0 Binary

• 3 is LESS THAN 4, so a 0 goes in the 4 place value column



Next step --

• That’s right! Evaluate 3 with the next Place Value column (2).


128 64 32 16 8 4 2 1 Place Value

1 1 0 1 1 0 ? Binary

Next step --

128 64 32 16 8 4 2 1 Place Value

1 1 0 1 1 0 1 ? Binary

• Correct! A 1 goes in the 2 Place Value column because 3 is GREATER THAN 2.

• Next, Subtract 3 from 2: 3

- 2 1

• Finally, evaluate 1 with the next Place Value column (1). • Does a 1 or a 0 go in the 1 Place Value column?

Final Answer

128 64 32 16 8 4 2 1 Place Value

1 1 0 1 1 0 1 1 Binary

• Correct! A 1 goes in the 1 Place Value column because 1 is EQUAL TO 1

• You’re Done! Now just write the digits from each of the columns, beginning with the MSB:

11011011 is the binary equivalent of 219

So we have converted one octet of the given IP address to binary.

Write it in the chart

Separate the IP address & Subnet Mask into octets

10 127 96 219 Decimal

11011011 Binary

We still have to convert the other three octets of this IP address to binary.

Not to mention, we still have to do the conversion on the Subnet mask.

Let’s get started!

Do the conversionNow you do the conversion for the other octets in the IP address

10.127.96.127. Don’t cheat and use the calculator!Work out the conversion using the binary conversion chart. Refer to pages

13 – 26 if you get stuck.

128 64 32 16 8 4 2 1 Place Value

Binary

128 64 32 16 8 4 2 1 Place Value

Binary

96

10

127

128 64 32 16 8 4 2 1 Place Value

Binary

Conversion Answers

Now check your work. Did come up with the following binary values for each octet?

128 64 32 16 8 4 2 1 Place Value

0 1 1 1 1 1 1 1 Binary

128 64 32 16 8 4 2 1 Place Value

0 1 1 0 0 0 0 0 Binary

96

10

127

128 64 32 16 8 4 2 1 Place Value

0 0 0 0 1 0 1 0 Binary

Awesome! Now record the binary value of each octet in the Write it in the chart

Record Binary values for each octet

10 127 96 219 Decimal

00001010 01111111 01100000 11011011 Binary

Now we have the binary representation of the given IP address.

Now it’s time to do more decimal to binary conversion.

We need to convert the subnet mask from decimal to binary as well.

Do you remember the first step?

If you chose separate the Subnet Mask into octets, that is correct.

If you recall, the given Subnet Mask for our module is 255.255.255.0

Fill out this chart, separating the octets of the Subnet Mask into the four columns of the Decimal row.

Separate Subnet Mask into octets

? ? ? ? Decimal

Binary

This chart shows the correct separation of the octets in the Subnet Mask. Did you get it right?

Octet Separation Answer

255 255 255 0 Decimal

Binary

Do you remember the next step?

Convert the subnet mask to binaryThat’s right – do the binary to decimal conversion. There are only two

numbers to convert: 0 and 255.Now you do the conversion for the other octets in the IP address

10.127.96.127. Don’t cheat and use the calculator!Work out the conversion using the binary conversion chart. Refer to pages

13 – 26 if you get stuck.

128 64 32 16 8 4 2 1 Place Value

Binary

0

255

128 64 32 16 8 4 2 1 Place Value

Binary

Do the conversion

Did you get these values when you did the conversion?

Great. Now, fill out the octet chart

128 64 32 16 8 4 2 1 Place Value

1 1 1 1 1 1 1 1 Binary

0

255

128 64 32 16 8 4 2 1 Place Value

0 0 0 0 0 0 0 0 Binary

This chart shows the correct separation of the octets in the Subnet Mask.

Did you get perform the conversion correctly?

Answer

255 255 255 0 Decimal

11111111 11111111 11111111 00000000 Binary

Ok so let’s review where we are so far….

√ Separate the IP address & Subnet Mask into octets

First step, complete


IP Address 10 127 96 219


√ Convert each octet from decimal to binary

Second Step, complete


IP Address 10 127 96 219

Subnet Mask 11111111 1111111 11111111 00000000

IP Address 00001010 01111111 01100000 11011011



→ Perform an AND on the IP address & Subnet Mask

Step Three: Perform an AND Operation


IP Address 10 127 96 219

Subnet Mask 11111111 11111111 11111111 00000000

IP Address 00001010 01111111 01100000 11011011

Subnet Mask 11111111 11111111 11111111 00000000

IP Address 00001010 01111111 01100000 11011011

AND

Perform an AND? What does THAT mean?

Boolean AND rulesBoolean is a type of math. A Boolean AND is a mathematical operation that takes two binary

numbers and combines them into one number.Here are the rules to the Boolean AND operation:

0 + 0 = 00 + 1 = 01 + 0 = 01+ 1 = 1

For example, to AND the following binary numbers:111100

You would perform the Boolean operation on each pair of numbers, starting with the LSD:

1 1 11 0 01 0 0

Or:111100100

Let’s try an example.

What is the result of the Boolean AND of the following binary numbers?

Remember: Perform the Boolean operation on each pair of numbers, starting with the LSD.

0100111

1100100

Boolean AND practice

Boolean AND answer

Is this the answer you got?0100111

1100100

0100100

Great!

Now perform an AND operation on the binary version of the IP and Subnet Mask we have been evaluating during this module:

Subnet Mask 11111111 11111111 11111111 00000000

IP Address 00001010 01111111 01100000 11011011

AND

Boolean AND answer

Is this the answer you got?

Fantastic! Now it’s time to move to the next step.

Subnet Mask 11111111 11111111 11111111 00000000

IP Address 00001010 01111111 01100000 11011011

AND 00001010 01111111 01100000 00000000

Let’s review the steps we’ve completed so far:



√ Perform an AND on the IP address & Subnet Mask

That means we are almost done!

→ Convert the result of the AND operation from binary to decimal



IP Address 10 127 96 219

Subnet Mask 11111111 1111111 11111111 00000000

IP Address 00001010 01111111 01100000 11011011

Subnet Mask 11111111 11111111 11111111 00000000

IP Address 00001010 01111111 01100000 11011011

AND 00001010 01111111 01100000 00000000

AND ? ? ? ?

We’ll use the binary conversion chart to convert a binary number to decimal.

In the chart, write the place value for the column under every one in the binary number.

Next, add up all the numbers in the Decimal Row.

128 + 32 + 4 + 2 = 166

Write the sum of the numbers in the Decimal Row in the Decimal Value Row. This is the decimal equivalent of the binary number

Rules for converting from binary to decimal

128 64 32 16 8 4 2 1 Place Value

0 1 1 0 0 1 1 0 Binary

128 32 4 2 Decimal

Decimal Value

128 64 32 16 8 4 2 1 Place Value

0 1 1 0 0 1 1 0 Binary

128 32 4 2 Decimal

166 Decimal Value

Step 4: Convert the AND result from Binary to Decimal

AND 00001010 01111111 01100000 00000000

128 64 32 16 8 4 2 1 Place Value

0 0 0 0 1 0 1 0 Binary

Decimal

Decimal Value

128 64 32 16 8 4 2 1 Place Value

0 1 1 1 1 1 1 1 Binary

Decimal

Decimal Value

Now it’s your turn! Convert each section of the AND result from Binary to decimal.

128 64 32 16 8 4 2 1 Place Value

0 1 1 0 0 0 0 0 Binary

Decimal

Decimal Value

128 64 32 16 8 4 2 1 Place Value

0 0 0 0 0 0 0 0 Binary

Decimal

Decimal Value

Results

AND 11000000 10101000 00000001 00000000

128 64 32 16 8 4 2 1 Place Value

0 0 0 0 1 0 1 0 Binary

8 2 Decimal

10 Decimal Value

128 64 32 16 8 4 2 1 Place Value

0 1 1 1 1 1 1 1 Binary

64 32 16 8 4 2 1 Decimal

127 Decimal Value

Did you get the same results?

128 64 32 16 8 4 2 1 Place Value

0 1 1 0 0 0 0 0 Binary

64 32 Decimal

96 Decimal Value

128 64 32 16 8 4 2 1 Place Value

0 0 0 0 0 0 0 0 Binary

Decimal

0 Decimal Value

Let’s review the steps we’ve completed so far:



√ Perform an AND on the IP address & Subnet Mask

√ Convert the result of the AND operation from binary to decimal

There is only one more step!

→ Write the converted number in dotted decimal notation.



IP Address 10 127 96 219

Subnet Mask 11111111 1111111 11111111 00000000

IP Address 00001010 01111111 01100000 11011011

Subnet Mask 11111111 11111111 11111111 00000000

IP Address 00001010 01111111 01100000 11011011

AND 00001010 01111111 01100000 00000000

AND 10 127 96 0

Step 5: Write the converted number in dotted decimal notation

This step is straight forward. Write the converted value of the AND operation in dotted decimal format.

Network Address = 10.127.96.0

AND 10 127 96 0

Final Practice

We’ve practiced the individual steps needed to find the Network Address from an IP Address and Subnet Mask.

Now you get to practice doing the entire thing on your own. Using the following IP Address and Subnet Mask, determine the pair’s Network Address.

Feel free to use any of the aides in this lesson, but do not use a calculator!

IP Address: 192.168.94.211

Subnet Mask: 255.255.0.0

Network Address: ________________

Final Answer

Did you get the correct answer?

IP Address: 192.168.94.211

Subnet Mask: 255.255.0.0

Network Address: 192.168.0.0

Fantastic!!

Now please proceed to the Post-Test to see if you are ready to proceed to the next level in the world of networking.

Determine a node’s IP Network Address Gina Minks EME5603 Fall 2008 Final Project For EMC...

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