1. PREPARED BY
Ms. NEERAJ BHARDWAJ
Assistant Professor, Computer Science
Poornima Institute Of Engineering and
Technology
Introduction to Computer Network &
IP(Internet Protocol) Addressing

2. Index
 History Computer Network
 IP Introduction
 IP addressing WITH CLASSFULL ADDRESSING
 Subnetting mASK with Examples

3. History
 Computer network started establishing in Late 60’s.
 In 1978 ISO (International Standard Organization)
proposed a new model known as OSI (Open System
Interface) model for networking.
 OSI model has 7 layers.
 An updated OSI model in TCP/IP (Transmission Control
Protocol/ Internet Protocol) was developed and merged
on 1st January 1983 with ARPANET (The Advanced
Research Projects Agency Network).
 The TCP/IP model has 4 layers which strictly follow the 7
layers of OSI model.

4. What is a Computer Network?
It is a system containing any combination of computers, computer
terminals, printers, audio , visual display devices or telephones
interconnected by telecommunication equipment or cables used to
transmit or receive information.
The Network Diagram

5. Network Classification By Their Components Role

7. Applications of Computer Network :
 Sharing of resources such as printers
 Sharing of expensive software's and database
 Communication from one computer to another computer
 Exchange of data and information among users via network
 Sharing of information over geographically wide areas.

8. Network Benefits
The network provided to the users can be divided into two
categories:
Sharing
Connectivity
Sharing Resources
Hardware Sharing: A network which allows users to share
many hardware devices such as printers , modems, fax
machines, CD ROM, players, etc.
Software Sharing: sharing software resources reduces the
cost of software installation, saves space on hard disk.

9. Introduction
 The IP (Internet Protocol) is basically a unique
address of any device by which the device can
communicate with other devices or communicate
world wide in terms of Internet.
There are two basic Types of IP address.
 IPv4 (IP version 4) (Earlier technology still used by
70% devices)
 IPv6 (IP version 6) (Newer version as the
addresses range is about to complete of IPv4)
 IPv4 (The address is divided into four parts each
having 8 bits and separated by dotted decimal
point and usually written in decimal for easy
understanding)

10. IP addressing Basic classfull addressing
 An IP address basically a 32-bit address that
universally defines unique connection of host
or a router to the Internet. IP address is
unique.
 Address space of IPv4 is 232.
 32 bit is divided into 4 equal parts of 8-8 bits
separated by dotted decimal notation. It is in
the range of minimum 0.0.0.0 to
255.255.255.255.
 Each 8 bit group is known by OCTET.

11. Rules for assigning Host ID:
• The Host ID is used to determine the host within any network. The
Host ID is assigned based on the following rules:
• The Host ID must be unique within any network.
• The Host ID in which all the bits are set to 0 cannot be assigned as it is
used to represent the network ID of the IP address.
• The Host ID in which all the bits are set to 1 cannot be assigned as it is
reserved for the multicast address.

12. Rules for assigning Network ID
• If the hosts are located within the same local network, then they
are assigned with the same network ID. The following are the
rules for assigning Network ID:
• The network ID cannot start with 127 as 127 is used by Class A.
• The Network ID in which all the bits are set to 0 cannot be
assigned as it is used to specify a particular host on the local
network.
• The Network ID in which all the bits are set to 1 cannot be
assigned as it is reserved for the multicast address

13. Class Higher bits NET ID bits HOST ID
bits
No.of
networks
No.of hosts
per
network
Range
A 0 8 24 27 224 0.0.0.0 to
127.255.2
55.255
B 10 16 16 214 216 128.0.0.0
to
191.255.2
55.255
C 110 24 8 221 28 192.0.0.0
to
223.255.2
55.255
D 1110 Not
Defined
Not
Defined
Not
Defined
Not
Defined
224.0.0.0
to
239.255.2
55.255
E 1111 Not
Defined
Not
Defined
Not
Defined
Not
Defined
240.0.0.0
to
255.255.2
55.255

14. An IP address consist of a NETWORK ID and
HOST ID.

15. Classes of IP addresses
Class A
In Class A, an IP address is assigned to those networks that
contain a large number of hosts.
o The network ID is 8 bits long.
o The host ID is 24 bits long.
In Class A, the first bit in higher order bits of the first octet is
always set to 0 and the remaining 7 bits determine the network
ID. The 24 bits determine the host ID in any network.

17. The total number of networks in Class A = 27 = 128
network address
The total number of hosts in Class A = 224 - 2 =
16,777,214 host address
.

18. Example: 64.0.0.0
(this is only network address)
 Suppose 64.255.255.255 is Direct broadcasting
address of an organization. If any person wants to
send the message to all the hosts of university then
he uses DB IP address . By this all will receive the
same message in the organization.
 DBA address is fixed and unique.
 64.0.0.1 is the first IP address of this network.

20. 64.0.0.8 belongs to which network?
 The network ID of any address can be calculate
only by Default mask.
 Default mask of class A is 255.0.0.0
 We apply AND operation on this.

22. Class B
 In Class B, an IP address is assigned to those networks that range
from small-sized to large-sized networks.
o The Network ID is 16 bits long.
o The Host ID is 16 bits long.
 In Class B, the higher order bits of the first octet is always set to
10, and the remaining14 bits determine the network ID. The
other 16 bits determine the Host ID.
 The total number of networks in Class B = 214 = 16384 network
address
 The total number of hosts in Class B = 216 - 2 = 65534 host
address

24.  Most of big university try to take class B network.
 First 16 bits defines network and remaining 16 bits
defines host parts.
 It has a highest nos. of address 230.which is about
65,536.

25. Example: 130.2.3.4
 We take a simple IP address of a host. First we will
check it lies between the range of 128 to 191.
 The network ID of any address can be calculate only
by Default mask.
 Default mask of class B is 255.255.0.0
 We apply AND operation on this.

27. Class C
 In Class C, an IP address is assigned to only small-sized
networks.
o The Network ID is 24 bits long.
o The host ID is 8 bits long.
 In Class C, the higher order bits of the first octet is always
set to 110, and the remaining 21 bits determine the network
ID. The 8 bits of the host ID determine the host in a
network.
 The total number of networks = 221 = 2097152 network
address
 The total number of hosts = 28 - 2 = 254 host address

28.  A local area network use Class C IP address to
connect with network.
 This IP range from 192 to 223.
 First 24 bits defines network ID and remaining
8 bits defines host parts.It has a highest nos.
of address 229.which is about 256.

30. Example: 194.2.3.4
 We take a simple IP address of a host. First to
check it lies between range 192 – 223.
 The network ID of any address can be calculate
only by Default mask.
 Default mask of class C is 255.255.255.0
 We apply AND operation on this.

32. Class-D
 In Class D, an IP address is reserved for multicast addresses.
 The higher order bits of the first octet is always set to 1110 and
the remaining bits determines the host ID in any network.
 IP range from 224 to 239.
 It is not usually use in general applications.
 It is use in Special purpose applications known as Multicast.
 In Class D not available number of Network ID and Number of
Host ID.
 IP address reserved for multicasting group, Email- broadcast etc.

33.  Class D reserved for any group, if any group create
related to research area. They can use this class D.
Disadvantages:
 Approximately 250 million IP addresses waste because
in all over world large group created.

34. Class-E
• In Class E, an IP address is used for the future use or for the
research and development purposes.
• The higher order bits of the first octet is always set to 1111,
and the remaining bits determines the host ID in any
network.
• IP range from 240 to 255. It is not usually use in
general applications.
This type of IP address class is mostly used for the
experimental or future use.

35. Needof Different IP Address
• IP address is the important key to find the physical
location of the particular computer system.
• It works similar to the home address by the
identification of that anything reaches to your house.
To communicate in the network each electronic
device uses IP address.
• To identify the network size these IP address is
categorized into various classes. All these types of IP
address is assigned to the organizations, businesses or
government operations.

36. IP address Uses and Security
• For the security reasons many people hide IP address. Whereas some
of them want to locate IP address to find out the visitors of the site.
• To locate IP address you can use free service of www.ip-
location.khozz.com . It provides various services to know IP
location of the unknown email sender, facebook friends’ location,
website visitors etc.

37. Subnetting is the process to divide a Big network in a small network for ease of access.
University Network
Library
Medical SchoolEngineering
School
Subnetting is the process of dividing a network & its
IP addresses into segments, each of which is called
a subnetwork or subnet.
The subnet mask is the 32-bit number that the
router uses to cover up the network address to
show which bits are being used to identify the
subnet

38.  We take a example of university, very difficult to
maintain a big university .
 We know in Class A 2^24 host possible in a network.
 But all Host maintain in a network is very difficult.
 We divided this in a small parts, which can be easily
handle.

39. For example we take a network IP ADDRESS in Class C :
200.10.20.0
In class C Number of Host = 256
Useable host = 254
• Here divide the network in two logical form: S1
and S2
 200 . 10 . 20 . 0 ( IP address of the network)
• First three octet to represents the network ID and
Last octet to represents the Host ID.

42. Basic Idea of Subnetting
 Subnets can be freely assigned within the
organization
 Internally, subnets are treated as separate
networks
 Subnet structure is not visible outside the
organization

43. Advantages of subnetting
 With subnetting, IP addresses use a 3-layer hierarchy:
 Network
 Subnet
 Host
 Improves efficiency of IP addresses by not consuming an entire
address space for each physical network.
 Reduces router complexity. Since external routers do not know
about subnetting.
 The complexity of routing tables at external routers is reduced.
 Note: Length of the subnet mask need not be identical at all sub
networks.

44. THANK YOU