The document discusses subnetting, which is dividing a large network into smaller subnetworks. It provides examples of fixed length subnet masking (FLSM) to divide Class C and Classless Inter-Domain Routing (CIDR) networks into multiple subnetworks, assigning IP addresses and subnet masks. Exercises are provided to practice subnetting networks into multiple subnetworks to support different numbers of users.

1. Subnetting
Nadira Islam
Department of Software Engineering
Daffodil International University

2. Sub netting
 Divide a big network into smaller
network
 FLSM-
 Dive big network into smaller network
containing fixed length

4. FLSM for Classful Addressing
195.20.25.1
Class: C
Subnet mask: 255.255.255.0
Network IP: 195.20.25.0
Broadcast IP: 195.20.25.255
Host’s IP’s:
195.20.25.1
195.20.25.2
195.20.25.3
.
.
195.20.25.253
195.20.25.254

5. Divide into two small network
195.20.25.0
11000011 00010100 00011001 00000000
Subnet 1:
Network IP:11000011 00010100 00011001 00000000
Subnet Mask:11111111 11111111 11111111 10000000
Broadcast IP:11000011 00010100 00011001 01111111
Host IP’s:11000011 00010100 00011001 00000001
11000011 00010100 00011001 00000010
11000011 00010100 00011001 00000011
…………………………..
11000011 00010100 00011001 01111101
11000011 00010100 00011001 01111110
Subnet 2:
Network IP:11000011 00010100 00011001 10000000
Subnet Mask:11111111 11111111 11111111 10000000
Broadcast IP:11000011 00010100 00011001 11111111
Host IP’s:11000011 00010100 00011001 10000001
11000011 00010100 00011001 10000010
11000011 00010100 00011001 10000011
…………………………..
11000011 00010100 00011001 11111101
11000011 00010100 00011001 11111110

6. FLSM for CIDR
193.10.0.0/20
11000001 00001010 00000000 00000000
Subnet mask: 11111111 11111111 11110000 00000000
Network IP: 11000001 00001010 00000000 00000000
193.10.0.0
Broadcast IP: 11000001 00001010 00001111 11111111
(193.10.15.255)
Host IP’s=
11000001 00001010 00000000 00000001
11000001 00001010 00000000 00000010
11000001 00001010 00000000 00000011
11000001 00001010 00000000 00000100
.
.
.
11000001 00001010 00001111 11111110

7. Divide the given Network into two network
Subnet 1:
Network IP: 11000001 00001010 00000000 00000000
Subnet mask: 11111111 11111111 11111000 00000000
Broadcast IP: 11000001 00001010 00000111 11111111
Host IP’s:
11000001 00001010 00000000 00000001
11000001 00001010 00000000 00000010
……………………………
11000001 00001010 00000111 11111110
Subnet2:
Network IP: 11000001 00001010 00001000 00000000
Subnet mask: 11111111 11111111 11111000 00000000
Broadcast IP: 11000001 00001010 00001111 11111111
Host IP’s:
11000001 00001010 00001000 00000001
11000001 00001010 00001000 00000010
……………………………
11000001 00001010 00001111 11111110

8. Exercise
1. 95.10.20.128/26, divide into two sub
network.
2. 198.168.2.0,divide into four sub
network.
3. If you have a network as
192.168.128.0, but in your office if
you need to create four different
networks which will server 10, 7, 8, 5
users in each. How you can do this ?