ipv4 subnetting
DESCRIPTION
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. - PowerPoint PPT PresentationTRANSCRIPT
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)
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
IP ADDRESS REVIEW- CLASS A
Range:
Default Subnet Mask:
Which octets are Network & Host?
How many hosts available?
Give an example IP & SM:
IP ADDRESS REVIEW- CLASS B
Range:
Default Subnet Mask:
Which octets are Network & Host?
How many hosts available?
Give an example IP & SM:
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:
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
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
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
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
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.