Transcript Determine a node’s IP Network

Determine a node’s IP Network
Address
Gina Minks
EME5603 Fall 2008 Final Project
For EMC Employees
Introduction
In 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.
Interne
t
Sales
Engineering
QA
Why take this module?
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.
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.
Objectives
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.
•
•
•
•
•
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
Review of terms
Before we get started, let’s go over a few terms you will need to know to
complete this module.
2
1
1.1
2.2
3.3
4.
192.168.1.101
3
Octet:
8 consecutive bits, or one byte. IP addresses have 4 octets
MSD: Most Significant Digit
This is the left most digit, or the digit with the greatest value in the number
LSD: Least Significant Digit
This is the right-most digit, or the digit with the least value in the number
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!
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?
Sales
Engineering
QA
Steps to find the network ID
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
•
•
•
IP Address
192
168
1
101
Subnet Mask
255
255
255
0
Convert each octet from decimal to binary
IP Address
11000000
10101000
00000001
01100101
Subnet Mask
11111111
1111111
11111111
00000000
Perform an AND on the IP address & Subnet Mask
IP Address
11000000
10101000
00000001
01100101
Subnet Mask
11111111
11111111
11111111
00000000
AND
11000000
00000001
00000000
convert the result of step three from binary to decimal
AND
•
10101000
192
168
1
Write the converted number in dotted decimal notation.
This is the network IP Address: 192.168.1.1
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
Separate the IP address & Subnet Mask into octets
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.
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
1. Write a 1 in the binary
conversion chart column
1. Write a 0 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
4. Write each number in the
conversion chart out – this is
the binary number
4. Write each number in the
conversion chart out – this is
the binary number
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
Binary
1
• 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?
128
64
1
?
32
16
8
4
2
1
Place Value
Binary
ANSWER
128
64
1
1
32
16
8
4
2
1
Place Value
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
1
1
?
16
8
4
2
1
Place Value
Binary
ANSWER
128
64
32
1
1
0
16
8
4
2
1
Place Value
Binary
• 27 is LESS THAN 32, so a 0 goes in the 32 place value column
• You are doing great! Keep going!
• YOU TRY IT:
What do you do next?
Next step -• That’s right! Evaluate 27 with the next place value (16).
• YOU TRY IT:
What number goes in the 16 place value column?
128
64
32
16
1
1
0
?
8
4
2
1
Place Value
Binary
ANSWER
128
64
32
16
1
1
0
1
8
4
2
1
Place Value
Binary
• 27 is MORE THAN 16, so a 1 goes in the 16 place value column
• You are doing great! Keep going!
• YOU TRY IT:
What do you do next?
Next step -• That’s right! Subtract 16 from 27:
27
-16
11
• Now evaluate 11 with the next Place Value column (8).
• YOU TRY IT:
What number goes in the 8 place value column?
128
64
32
16
8
1
1
0
1
?
4
2
1
Place Value
Binary
ANSWER
128
64
32
16
8
1
1
0
1
1
4
2
1
Place Value
Binary
• 11 is MORE THAN 8, so a 1 goes in the 8 place value column
• You are doing great! Keep going!
• YOU TRY IT:
What do you do next?
Next step -• That’s right! Subtract 8 from 11:
11
-8
3
• Now evaluate 3 with the next Place Value column (4).
• YOU TRY IT:
What number goes in the 4 place value column?
128
64
32
16
8
4
1
1
1
0
1
?
2
1
Place Value
Binary
ANSWER
128
64
32
16
8
4
1
1
0
1
1
0
2
1
Place Value
Binary
• 3 is LESS THAN 4, so a 0 goes in the 4 place value column
• You are doing great! Keep going!
• YOU TRY IT:
What do you do next?
Next step -• That’s right! Evaluate 3 with the next Place Value column (2).
• YOU TRY IT:
What number goes in the 2 place value column?
128
64
32
16
8
4
2
1
1
0
1
1
0
?
1
Place Value
Binary
Next step -• 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?
128
64
32
16
8
4
2
1
Place Value
1
1
0
1
1
0
1
?
Binary
Final Answer
• Correct! A 1 goes in the 1 Place Value column because 1 is EQUAL TO 1
128
64
32
16
8
4
2
1
Place Value
1
1
0
1
1
0
1
1
Binary
• You’re Done! Now just write the digits from each of the columns,
beginning with the MSB:
11011011 is the binary equivalent of 219
Separate the IP address & Subnet Mask into octets
So we have converted one octet of the given IP address to binary.
Write it in the chart
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 conversion
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.
96
128
64
32
16
8
4
2
1
Place Value
Binary
127
128
64
32
16
8
4
2
1
Place Value
Binary
10
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?
96
128
64
32
16
8
4
2
1
Place Value
0
1
1
0
0
0
0
0
Binary
128
64
32
16
8
4
2
1
Place Value
0
1
1
1
1
1
1
1
Binary
127
10
128
64
32
16
8
4
2
1
Place Value
0
0
0
0
1
0
1
0
Binary
Record Binary values for each octet
Awesome! Now record the binary value of each octet in the Write it in the
chart
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?
Separate Subnet Mask into octets
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.
?
?
?
?
Decimal
Binary
Octet Separation Answer
This chart shows the correct separation of the octets in the Subnet Mask. Did
you get it right?
255
255
255
0
Decimal
Binary
Do you remember the next step?
Convert the subnet mask to binary
That’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.
255
128
64
32
16
8
4
2
1
Place Value
Binary
0
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
255
128
64
32
16
8
4
2
1
Place Value
1
1
1
1
1
1
1
1
Binary
0
128
64
32
16
8
4
2
1
Place Value
0
0
0
0
0
0
0
0
Binary
Answer
This chart shows the correct separation of the octets in the Subnet Mask.
Did you get perform the conversion correctly?
255
255
255
0
Decimal
11111111
11111111
11111111
00000000
Binary
Ok so let’s review where we are so far….
First step, complete
√ Separate the IP address & Subnet Mask into octets
IP Address
10
127
96
219
Subnet Mask
255
255
255
0
Second Step, complete
√ Separate the IP address & Subnet Mask into octets
IP Address
10
127
96
219
Subnet Mask
255
255
255
0
√ Convert each octet from decimal to binary
IP Address
00001010
01111111
01100000
11011011
Subnet Mask
11111111
1111111
11111111
00000000
Step Three: Perform an AND Operation
√ Separate the IP address & Subnet Mask into octets
IP Address
10
127
96
219
Subnet Mask
255
255
255
0
√ Convert each octet from decimal to binary
IP Address
00001010
01111111
01100000
11011011
Subnet Mask
11111111
11111111
11111111
00000000
→ Perform an AND on the IP address & Subnet Mask
IP Address
00001010
01111111
01100000
11011011
Subnet Mask
11111111
11111111
11111111
00000000
AND
Perform an AND? What does THAT mean?
Boolean AND rules
Boolean 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=0
0+1=0
1+0=0
1+ 1 = 1
For example, to AND the following binary numbers:
111
100
You would perform the Boolean operation on each pair of numbers, starting with the LSD:
1
1
1
1
0
0
1
0
0
Or:
111
100
100
Boolean AND practice
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 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:
IP Address
00001010
01111111
01100000
11011011
Subnet Mask
11111111
11111111
11111111
00000000
AND
Boolean AND answer
Is this the answer you got?
IP Address
00001010
01111111
01100000
11011011
Subnet Mask
11111111
11111111
11111111
00000000
AND
00001010
01111111
01100000
00000000
Fantastic! Now it’s time to move to the next step.
Steps to find the network ID
Let’s review the steps we’ve completed so far:
√ Separate the IP address & Subnet Mask into octets
IP Address
10
127
96
219
Subnet Mask
255
255
255
0
√ Convert each octet from decimal to binary
IP Address
00001010
01111111
01100000
11011011
Subnet Mask
11111111
1111111
11111111
00000000
√ Perform an AND on the IP address & Subnet Mask
IP Address
00001010
01111111
01100000
11011011
Subnet Mask
11111111
11111111
11111111
00000000
AND
00001010
01111111
01100000
00000000
That means we are almost done!
→ Convert the result of the AND operation from binary to decimal
AND
?
?
?
?
Rules for converting from binary to decimal
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.
128
64
32
16
8
4
2
1
Place Value
0
1
1
0
0
1
1
0
Binary
4
2
128
32
Decimal
Decimal Value
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
128
64
32
16
8
4
2
1
Place Value
0
1
1
0
0
1
1
0
Binary
4
2
128
32
Decimal
166
Decimal Value
Step 4: Convert the AND result from Binary to Decimal
Now it’s your turn! Convert each section of 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
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
Did you get the same 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
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
Steps to find the network ID
Let’s review the steps we’ve completed so far:
√ Separate the IP address & Subnet Mask into octets
IP Address
10
127
96
219
Subnet Mask
255
255
255
0
√ Convert each octet from decimal to binary
IP Address
00001010
01111111
01100000
11011011
Subnet Mask
11111111
1111111
11111111
00000000
√ Perform an AND on the IP address & Subnet Mask
IP Address
00001010
01111111
01100000
11011011
Subnet Mask
11111111
11111111
11111111
00000000
AND
00001010
01111111
01100000
00000000
√ Convert the result of the AND operation from binary to decimal
AND
10
127
96
There is only one more step!
→ Write the converted number in dotted decimal notation.
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.
AND
10
127
96
Network Address = 10.127.96.0
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:
Subnet Mask:
Network Address:
192.168.94.211
255.255.0.0
________________
Final Answer
Did you get the correct answer?
IP Address:
Subnet Mask:
Network Address:
192.168.94.211
255.255.0.0
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.