The document discusses subnet masking and subnetting. It explains that subnet masking allows you to identify the network and host portions of an IP address by using 1s and 0s in the subnet mask. Performing a bitwise AND of the IP address and subnet mask yields the network address. Subnetting separates a classful network into smaller subnetworks to better utilize IP addresses and support network hierarchy. The document provides examples of subnet masks for class A, B and C networks.

1. CONTINUOUS ASSESMENT-(CA1)
AY-2022-2023(EVEN SEM)
(MAKAUT EXAMINATION)
Assessment Type- Presentation
1
BUDGE BUDGE INSTITUTE OF TECHNOLOGY
Affiliated to MAKAUT(formerly WBUT)& Approved by AICTE, NAAC Accredited
Kolkata - 700 137, West Bengal, India
Phone : 033 2482 0676 / 0670
http://www.bbit.edu.in
Department of Computer Science and Engineering
NBA (National Board of Accreditation) valid from Academic Year 2021-2022 TO 2023-2024 i.e. upto 30-06-2024.
University Roll Number: 27600120126
Name of the Student: SWAPNAMAY SAMUI
Course Code: PCC-CS602
Course Name: COMPUTER NETWORK
Semester 6th
Year 3rd
Department Computer Science and Engineering
Topic of Presentation SUBNET MASK

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In class A full addressing most of the IP
addressing are wasted, whereas in class C IP
address are not available. So, in order to
utilize the IP address concept of subnet is
introduce.
Subnet support3-level of hierarchy-
Level-3
Level-2
Level-1 Network_Id
Subnet-1
Host-1 Host-2
Host-
K
Subnet-2
Host-1
Host-
m
Subnet-
n
Host
-1
Host
-l
Introduction:

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Literature Survey:
Each host in a LAN has a subnet mask. The
subnet mask is an octet that uses the number 255 to
represent the network address portion of the IP
address and a zero to identify the host portion of
the address . For example, the subnet mask
255.255.255.0 is used by each host to determine
which LAN or class it belongs to. The zero at the end
of the subnet mask represents a unique host within
that network.

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During the era of classful addressing,
subnetting was introduced. If an organization
was granted a large block in class A or B, it
could divide the addresses into several
contiguous groups and assign each group to
smaller networks (called subnets) or, in rare
cases share part of the addresses with
neighbors.
The job of the subnet is to carry messages
from host to host.
Subnet masking :

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Subnet masks apply only to Class A, class B
or Class C IP addresses.
The subnet Mask is like a filter that is
applied to a message’s destination IP
address.
Its objective is to determine if the local
network is the destination network.
Subnet masking :

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Subnet masking :

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Applying a subnet mask allows you to identify
the network and Host parts of the address. A router will
then determine whether the address is local or remote.
Network bits are masked as 1s
Host bits are masked as 0s
Class A – 255.0.0.0
11111111.00000000.00000000.00000000
Class B – 255.255.0.0
11111111.11111111.00000000.00000000
Class C – 255.255.255.0
11111111.11111111.11111111.00000000
Subnet masking :

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Performing a bitwise logical AND between the
IP address and the subnet mask results in the
network address
Ex: Class - B 140.179.240.200
10001100.10110011.11110000.11001000
11111111.11111111.00000000.00000000
10001100.10110011.00000000.00000000
Network Address = 140.179.000.000
Subnet masking :

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Using /24 subnet...
190.52.1.2
190.52.2.2
190.52.3.2
Network Network Subnet Host
But internal routers think all
these addresses are on different
networks, called subnetworks
Internet routers still “see” this net as 190.52.0.0
Class B Network Network Host Host
Given the Class B address 190.52.0.0
Subnet Example

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With the rapid growth of internet & the ever-
increasing demand for new addresses, the standard
address class structure has been expanded by borrowing
bits from the host portion to allow for more networks.
Under this addressing scheme ,called Subnetting,
separating the network & Host requires a special process
called Subnet Masking.
Conclusion:

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Reference:
 https://mvrk2016.files.wordpress.com/2016/02/3-ip-
address-subnet-mask-final.ppt
 https://www.javatpoint.com/dbms-tutorial
 https://www.tutorialspoint.com/dbms/index.htm
 https://www.geeksforgeeks.org/dbms/

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