This document discusses IP addressing and subnetting. It begins by defining what an IP address is and its two main functions of identifying devices and their location on the network. It then covers the basics of networking and addressing schemes. The main topics discussed include the classes of IPv4 addresses (A, B, C, D, E), private IP addresses, reserved addresses, and how packets travel across a network.

1. Vishwesh Bhat
ME CMPN
Sub: ACND
Topic: IP address &
Subnetting
Roll no: 01

2. LET’S KNOW ABOUT CBCB
ADDRESS
It declared the host device and its
location.
IP addresses axcbxbre unique
numerical labels assigned to each
device.
Yes, every device that is connected to
the INTERNET has an IP Address.
And no two devices could have the
same IP Addresses.

3. 1. Identifies the network interface of host
devices
2. Provides the location of the host on the
network
These two functions together allow us to calculate the
path to any device in the network.
Well, IP addrebvbssing was never a cakewalk as it
is now.
Initially, we had 32-bit long addresses.
This was very convenient in the early days.
It gave us more than 4 billion addresses.
This Scheme or Technique was known as IPv4.
IP XNCVNADDRESS HAS TWO
FUNCTIONS :

4. XBN XBC
But soon we started running short of hddhhaddresses.
This was because the Internet had become more common
by now.
Hence we had to come up with something new.
That’s when dfhdfhinto action.
IPv6 was a 128-bit long address.
This meant 340 trillion trillion dhdhdfh.
Well, do you think this would be enough in the near future?
Well, be it as it may, IPv4 is important when learning
Computer networks.
Afterall its drawbacks gave birth to IPv6.

5. DHNSDFH.
In this presentation, we shall learn about IPv4 and
subnetting.
So, before we start with IPv4 Scheme, Let's catch up with
some of the basics of Networking.
This is said to be an era of computers.
There have been significant changes.
When a device is connected to other computing devices,
they form a Netfhshork.

6. BASICS HS.
A network can hsxhshhosts.
Generally, via some shared media which can be wired or
wireless.
This enables the host to share/exchange information
over the media.
A computer network can be as simple as 2 Computers
connected via a single cable.
Or, it can be as complicated as 1000s of devices
connected via wireless or wired media.
The Internet is a network of networks.
It can be said as the biggest network of interconnected
networks, mostly wireless.

7. HON THE
NESXGHSXHK
Now, to communicate with any device, they should be able to
identify each other.
To identify a device on the network, We have two ways.
MAC Address and IP Address.
MAC address is a factory coded 48-bits hardware address.
This is used when devices are logically connected.
IP Address is used when the devices are not logically
connected.
A logical address is given to all hosts connected to the Internet.
This logical address is called the Internet Protocol Address.
Let's Learn more about the modes of addressing in IPv4.

8. HIERARCHICAL ADDRESSING
SCHEME
IPv4 uses a hierarchical addressing scheme.
An IP address, which is 32 bits in length.
It is divided into two or three parts.
A single IP address can contain information about the network, its
sub-network, and the host.
This scheme enables the IP Address to be hierarchical, where a
network can have many sub-networks, which can have many hosts.

9. WHAT ARE ADDRESS CLASSES?
Broadly, the IPv4 Addressing system is divided into five
classes of IP Addresses:
1. Class A
2. Class B
3. Class C
4. Class D
5. Class E
Each of these classes is exclusively a range of valid IP
Addresses.
These are assigned to cover the needs of different types of
organizations.

10. IPV4 ADDRESSING SYSTEM
Class A Address
Leftmost bit = 0 defines Class A.
The remaining 7 bits define different networks. Theoretically, we can have
227 = 128 networks.
Net id = 7 bits + 1 bit class type.
Host id = 24 bits
i.e. each network can theoretically have 224 hosts.
Class A addresses are designed for organizations that may have a huge
number of computers attached to their networks.
0 Net id (7 bits) Host id (24 bits)

11. IPV4 ADDRESSING SYSTEM
Class B Address
Two Leftmost bits = 10 defines Class B.
The next 14 bits define different networks. We can have 214 = 16,384
class B networks.
Net id = 14 bits + 2 bit class type.
Host id = 16 bits
i.e. each network can theoretically have 216 hosts.
Class B addresses are designed for mid-size organizations that may have
a large computers attached to their networks.
1 0 Net id (14 bits) Host id (16 bits)

12. IPV4 ADDRESSING SYSTEM
Class C Address
Leftmost bit = 110 define Class C.
The next 21 bits define different networks. We can have 221 networks.
Net id = 21 bits + 3 bits class type.
Host id = 8 bits
i.e. each network can theoretically have 28 hosts.
Class C addresses are designed for small organizations that may have a
small number of computers attached to their networks.
1 1 0 Net id (21 bits) Host id (8 bits)

13. IPV4 ADDRESSING SYSTEM
Class D Address
The class D address is defined for multicasting. In this case, there is no
host id and no net id. The whole address is used for multicasting. The first
4 bits (1110) define the class type. The remaining 28 bits define different
multicast address.
Class E Address
The class E is reserved by the internet for special use: No net id, no-host
id. The leftmost 4 bits (1111) define the class.
1 1 1 0 Multicast Address

14. Class C Address
Class C IP addresses range from 192.0.0.x to 223.255.255.x.
The default subnet mask for Class C is 255.255.255.x.
Class C gives 2097152 (221) Network addresses and 254 (28-2) Host
addresses.
Class D Address
Class D has an IP address range from 224.0.0.0 to 239.255.255.255.
Class D is reserved for Multicasting.
In multicasting, data is not destined for a particular host.
Hence, there is no need to extract the host address from the IP address.
Class D does not have any subnet mask.
CLASS ADDRESSING

15. WHAT IS SUBNETTING
Subnetting is the practice of dividing a network into two or more
smaller networks.
It increases routing efficiency and enhances the security of the
network.
It also reduces the size of the broadcast domain.
Let’s take an example.
If we put more than 16000000 hosts in a single network,
due to broadcast and collision,
that network will never work.
If we put fewer hosts, then remaining addresses will be wasted.
Here’s when the subnet comes into action.

16. LET’S TAKE AN EXAMPLE.
The best example is your office or college Network.
We have one huge network: 10.0.0.0/75. All hosts are in the same subnet.
This has many disadvantages. All hosts are in the same domain.
A broadcast sent by any device will be processed by all hosts. This creates
lots of unnecessary traffic.
Each device can communicate with any other device on the network. This can
present security problems.
Subnetting helps us solve all our issues.
In large networks, for example- schools, different departments are grouped
into different subnets.
This is how it helps us in creating fuss-free communication.

17. RESERVED IP ADDRESS
There are a few reserved IPv4 addresses which cannot be used on the
internet.
These addresses serve a special purpose.
They cannot be routed outside the Local Area Network.
Let's learn about these more

18. PRIVATE IP ADDRESSES
Every class has some addresses, reserved as Private IP addresses.
These IPs can be used within a network, campus, company and are
private to it.
These addresses cannot be routed on the Internet.
So, packets containing these private addresses are dropped by the
Routers.

19. LOOPBACK IP ADDRESSES
The IP address range 127.0.0.0 – 127.255.255.255 is reserved for
loopback.
A Host’s self-address, also known as localhost address.
This loopback IP address is managed entirely by and within the
operating system.
They enable Server and Client processes on a single system to
communicate with each other.

20. LINK-LOCAL ADDRESS
A link-local address is an IPv6 unicast address.
Link-local address ranges from 169.254.0.0 -- 169.254.255.255.
Link-local addresses are not necessarily bound to the MAC address
Well, these are the three reserved IPv4 addresses.

21. HOW PACKET TRAVELS IN THE
NETWORK
So far we have only heard about IP addresses and packet flow.
In this last unit, we will learn how a packet flows in a network.
All the devices in IPv4, are assigned unique logical IP addresses.
Let's suppose there are 2 hosts in a network A and B.
A and B wish to communicate.
In order to do so, they need to have the physical address of the other:
The MAC Address.

22. To get the mac address, the host A broadcasts an ARP message.
A asks to give the MAC address whoever is the owner of the
destination IP address.
All the hosts on that segment receive the ARP packet.
But, only B has its IP matching with the one in the ARP message.
B will reply with its IP address.
The connection is established and A & B can now exchange data.
But, what if they are not on the same/local subnet?
Well, this has a different protocol

23. Step 1 is to acquire IP Address (DHCP)
When the user’s PC boots up, it searches for a DHCP server.
This is done to acquire an IP address.
For the same, the PC sends a DHCPDISCOVER broadcast.
This is received by one or more DHCP servers on the subnet.
They all respond with DHCPOFFER which includes all the necessary
details such as IP, subnet, gateway, DNS, etc.
The PC sends DHCPREQUEST packet in order to request the offered IP
address.
Finally, the DHCP sends a DHCPACK packet to tell the PC that it can
keep the IP for some given amount of time, that is known as IP lease.

24. The second step starts when you enter https://programminghub.io/
on your browser.
This is a domain name.
Your system does not know how to communicate with the server,
using the domain.
The PC sends a DNS query out on the network in order to obtain the
IP address.
The pre-configured DNS server responds to the query with the IP
address of the domain name specified.
This marks the end of step 2.

25. The last step is the ARP request.
This is quite similar to the one before.
Since the IP does not belong to the IP address range,
it is forwarded to the Gateway.
The Gateway in this scenario can be a router or a Proxy Server.
To obtain the MAC address of the Gateway, the client PC broadcasts
an ARP request.
The rest goes as usual.