Subnetting

Subnetting and Converting

By Houston McDonald and Drew McDonald

Im not sorry

Decimal Conversion

l0ll000l = 128+32+16+1

=177

​Example

Each Bit of a binary octet has a value

l l l l l l l l

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

So based on which bits are turned on will determine the decimal outcome.

How to convert to decimal

Practice Time

Multiple Choice

What is 1010 1110 in decimal?

• 172

• 174

• 176

• 178

Multiple Choice

What is a 1110 1111 in decimal?

• 237

• 243

• 239

• 241

Multiple Choice

What is 0101 0001 in decimal?

• 79

• 81

• 83

• 85

Multiple Choice

What is 1001 1010 in decimal?

• 154

• 156

• 152

• 158

Converting Decimal to Binary

How to convert decimal to binary

To convert to to decimal to binary all you do is what you did but in reverse. So by using the numerical value of each bit to add up to the number you are trying to convert from.

​Example

​What is 152 in binary

128+16+8=152

=1001 1000

Practice Time

Multiple Choice

What is 168 in binary?

• 1010 0100

• 0001 1010

• 1010 1000

• 1010 0111

Multiple Choice

What is 174 in binary?

• 1110 1111

• 1010 1110

• 1101 0010

• 1010 1100

Multiple Choice

What is 224 in binary?

• 1101 1111

• 1011

• 1110 0000

• 1111 000

Multiple Choice

What is 55 in binary?

• 0011 0111

• 0011 1001

• 0010 1111

• 0011 1110

Converting to Hex

1010 0111= 1010 | 0111

A 7

So 1010 0001 in hex would be A7

​Example

When converting to hex from binary you want to split the octet into two parts. Once split each part represents a different value going through 1-9,A-F.

A=10 B=11 C=12 D=13 E=14 F=15

How to convert to hex

Multiple Choice

Convert 1010 1001 to hex.

• A9

• AA

• A8

• A7

Multiple Choice

What is the binary for F6

• 1111 0110

• 1110 0111

• 0111 1010

• 1111 0101

Multiple Choice

What is 0111 1110 in hex?

• 7B

• 7F

• 7C

• 7E

Multiple Choice

What is 1110 0001 in hex?

• E1

• F1

• E0

• F0

Identifying usable host ID bits in a subnet mask.

192.168.20.1/28= 255.255.255.1111 0000

2^4-2 = 16-2=14

There are 14 usable host bits

​Example

To identify the host bits of a subnet mask you first need to convert it into binary. Once converted to binary you need to count the 0's in the mask. Once you figure that out you use the formula 2^x - 2

How to identify usable host ID bits.

Fill in the Blanks

How many usable host ID's are in a /19

Fill in the Blanks

How many host ID's are in a /24?

Fill in the Blanks

How many usable host ID's are there in a /22?

Fill in the Blanks

How many host ID's are in a /13

Fill in the Blanks

How many host bits are in a /14?

Identifying IP address Classes

What class is this IP: 192.168.17.32

The first octet of the IP address is 192 so the IP address 192.168.17.32

is a Class C address

Example

A IP address can be apart of 3 different classes: Class A(1-126), Class B(128-191), Class C(192-223) based on the first octet of the IP. Depending on the class of the address will determine which octets are host and network.

Identifying Classes

Multiple Choice

What class is the IP address 152.64.18.44?

• Class A

• Class B

• Class C

Multiple Choice

What class is the IP address 223.168.55.145

• Class A

• Class B

• Class C

Multiple Choice

What class is the IP address 55.48.56.88

• Class A

• Class B

• Class C

Multiple Choice

What class is the IP address 152.64.87.66

• Class A

• Class B

• Class C

Identifying if an IP address is valid

Is 192.168.6.0 a valid IP address.

192.168.6|0

192.168.6|0000 0000

No its not a valid IP address because the host section is all 0's

Example

​When identifying weather a IP address is valid for you need to identify what class the IP address is apart of.

A IP address can be apart of 3 different classes: Class A(1-126), Class B(128-191), Class C(192-223) based on the first octet of the IP. Depending on the class of the address will determine which octets are host and network. Class A(1|1.1.1), Class B(128.1|1.1), Class C(192.1.1|1). It will only be valid if the host or network part is not all 0's or all 1's.

Identifying valid IP addresses

Multiple Choice

Is 168.45.0.255 a valid IP address?

• True

• False

Multiple Choice

Is 192.168.0.255 a valid IP address?

• True

• False

Multiple Choice

Is 68.255.255.255 a valid IP address?

• True

• False

Multiple Choice

Is 192.168.17.25 a valid IP address?

• True

• False

Multiple Choice

Is 152.145.96.15 a valid IP address?

• True

• False