IPV4 SUBNETTING

Chapter 9a

Intro to Routing & Switching

OBJECTIVES Upon completion of this chapter, you

should be able to: Explain why routing is necessary for hosts on

different networks to communicate. Describe IP as a communication protocol used

to identify a single device on a network. Given a network and a subnet mask, calculate

the number of host addresses available. Calculate the necessary subnet mask in order

to accommodate the requirements of a network.

Describe the benefits of variable length subnet masking (VLSM)

IPV4 ADDRESSING

REVIEW

9.1

ADDRESSING REVIEW- 5Q

How many bits in an IPv4 address?32

How many octets in an IPv4 address?4

What’s the range of numbers in each octet?0-255

What are the bit values?128, 64, 32, 16, 8, 4, 2, 1

Convert 192.168.1.10611000000.10101000.00000001.01101010

CONVERSION PRACTICE 1

11100101 to decimal

10001110 to decimal

11111000 to decimal

11111111 to decimal

CONVERSION PRACTICE 2

192 to binary

224 to binary

47 to binary

115 to binary

IP ADDRESS REVIEW- CLASS A

Range:

Default Subnet Mask:

Which octets are Network & Host?

How many hosts available?

Give an example IP & SM:

CONVERT A 5 to binary

77 to binary

100 to binary

127 to binary

What’s in common with all of them?

IP ADDRESS REVIEW- CLASS B

Range:

Default Subnet Mask:

Which octets are Network & Host?

How many hosts available?

Give an example IP & SM:

CONVERT B 128 to binary

142 to binary

191 to binary

What’s in common here?

IP ADDRESS REVIEW- CLASS C

Range:

Default Subnet Mask:

Which octets are Network & Host?

How many hosts available, total & useable?

Give an example IP & SM:

CONVERT C 192 to binary

200 to binary

223 to binary

What’s common here?

OTHER CLASSES Class D

Multicasting

Class EExperimental Use

Private AddressesA-B-C-

SUBNET MASKS

9.2

SUBNET MASKS & SLASH

255.255.255.0How many total bits are on? (1’s)

11111111.11111111.11111111.00000000 /24 notation

255.255.0.0How many total bits are on? (1’s)

11111111.11111111.00000000.00000000 /16 notation

255.255.255.248How many total bits are on? (1’s)

11111111.11111111.11111111.11111000 /29 notation

ROUTERS, IP’S & SUBNET MASKS

Router ONLY knows which NETWORKS it is connected to!!!

Doesn’t care about individual hosts

It ANDs the IP & Subnet Mask

Result= DESTINATION NETWORK

Looks in routing table for destination network & sends it out the outgoing port

ANDING

CLASSFUL SUBNETTING

9.3

PARTS OF THE NETWORK

Network

Subnetwork

Hosts

SUBNETTING-SPLIT UP THE IP ADDRESS

Borrow bits from host portion to make new networks

Ask yourself…How many networks do you need?How many hosts per network are there?

SOME RULES FIRST… You MUST borrow at least 2 bits or leave at

least 2 bits Class C has 1 octet to borrow from Class B has 2 octets to borrow from Class A has 3 octets to borrow from

Remember the powers of 2 22= 4 23= 8 24= 16 25= 32 26= 64

Remember 2 you can’t use:

Network & Broadcast

199.72.101.0

199.72.101.0

1. 199.72.101.0-312. .32-.63 (.33-.62)3. .64-.95 (.65-.94)4. .96-.127 (.97-.126)5. .128-.159 (.129-.158)6. .160-.191

(.161- .190)7. .192-.223 (.191-.222)8. .224-.255

Total Range #3 Useable Range #2

Network ID 199.72.101.64 /27

Broadcast Address 199.72.101.95 /27

ASSIGN ADDRESSES

ROUTER…ACTION! A packet with a destination IP of

199.72.101.85 255.255.255.224 goes to a router It ANDs to come up with the NETWORK #

HOW TO WORK BACKWARDS

221.17.125.46 /28What class address?

C: Only deal with the last octet!255.255.255.24011111111.11111111.11111111.11110000How many bits borrowed?

4 24= 16 networks

How many bits left over? 4 24= 16 hosts per sub-network

WORK BACKWARDS Based on the IP address & SM, identify…

The network addressThe broadcast addressHow many bits were borrowedHow many bits were left over Is the address valid

WHAT’S WRONG? Are the hosts on the same network or

separate?

QUESTIONS What’s the broadcast address for

201.78.90.0 /24?201.78.90.255Default SM, no subnetting

Sam’s Beef Hut uses network 215.67.106.0 & 255.255.255.240 to create subnets. How many useable hosts can be created per network?14

QUESTIONS Which class gives you the most

hosts/network?A

Which class give you the most networks?C

Public IP addresses must be __________.

CLASSLESS SUBNETTING

CIDR VLSM You can subnet, for each unequal

networkYour address is 210.1.17.64 /26

Net A needs 37 hosts Net B needs 15 hosts Net C needs 100 hosts

CIDR BLOCK FOR ROUTER

Instead of having multiple subnet entries for each router port, CIDR uses the common bits to make ONE routing table address per port.

REVIEW- 4Q

REVIEW- 4Q

REVIEW & STUDY Complete the study guide handout

Take the quiz on netacad.com

Jeopardy review

SUMMARYIn this chapter, you learned:

IPV4 SUBNETTING

Chapter 9a

Intro to Routing & Switching