IPv4 Addresses And IPv6 Addresses

Jun 16 • Notes • 3586 Views • 2 Comments on IPv4 Addresses And IPv6 Addresses


An IPv4 address by this it indicates that it is the 32 bit address that properly defines the connection of the device in the unique manner.The length of the IPv4 address is of 32 bit.This is unique in the way as it defines only one connection to the internet.As we know that two devices in the internet can’t have the same address at the same time.

If a device is operating at the network having n number of connections then it needs to have n number of addresses.

These are universal as the addressing system must be accepted by any user who wants to be connected to the internet.

Address Space

The IPv4 that defines the address must have the particular address space.The address space is defined as the total number of the address used by the protocol.If the protocol uses M number of the bits for the address definition then it requires 2M number of the address space as each bit can have two different values of 0 or 1.

The IPv4 is a 32 bit address i.e. the address space is of 232 or 4,294,967,296.


There are two notations for the IPv4 address

1.Binary notation

2.Decimal notation

In this notation the address is represented as the 32 bit.Each octet is termed as the byte so the IPv4 address is referred to as the 32 bit address or 4-byte address.The example of the IPv4 address in the binary notation-

01110101 10010101 00011101 00000010


For the easier approach to read the IPv4 address it is written in the decimal notation with the decimal points separating the bytes.For example-

Classful Addressing

The IPv4 addressing uses the concept of classes and this architecture is called classful addressing.


In the classful addressing the total address space is divided into 5 classes i.e. A,B,C,D,E and each of the indivisual classes occupy some address space.We can find the class of the address when the address is either given in the binary notation or the dotted decimal notation.

The class can be identified by the first few bits or bytes..it has been clearly explained by the fig, below.

classful addressing explaination

classful addressing explanation


One problem with the concept of the classful addressing is that each class is divided into number of blocks and each block has a fixed size.When a block of address is requested by the group of the organization,then the address must be present in the classes A ,B or C.The class A address are designed for the large organizations with large number of the routers.Class B address were for the  middle level organizations with around some 10,000 number of the attached routers and the class C address were designed for the small organizations with lesser number of the routers.

Here the disadvantage of the classful addressing can be seen,as the class A block were meant for the large organizations and firms i.e.most of the address in the class A were wasted.Similarly the class B address block were also wasted as the blocks were too big for many of the middle level organizations.Where as the block C is too small for many of the firms.So in the classful addressing many of the available addresses were wasted.


 To overcome the flaws of the classful addressing the classless addressing were designed.In this there are no classes but the addresses are divided into the blocks.

Address Blocks

The size of the address block varies with the nature and the size of the entities.For example for the organizations it may be given thousand of the address blocks where as for the household purpose the only two or three address may be sufficient.

Restriction To simplify the handling of addresses:

1. The address in the block must be continuous one after the other.

2.The number of the address in the block must be of the power of .2.

3. The first address must be evenly divisible by the number of the addresses.

The better way to define the block of addresses is to select any address in the block and the mask which is 32-bit number in which n leftmost bits are 1s and 32-n rightmost bits are 0s

Network Address Translation (NAT)

The NAT enables the users to have large number of the address internally and one address or small set of the addresses externally.This has proved to be the helping hand when the shortage of the addresses have become a serious problem these days with the increases number of the users

Any organization can use range of the address defined by the NAT without the permission of the internet authorities.It is known that the addresses are reserved for the private applications.


Nat-router connection

Nat-router connection          



An IPv6 address consists of the 16 bytes.It is 128 bits long.In other words we can say that the IPv6 addresses are 128 bits long.

Hexadecimal Colon Notation

The IPv6 uses the hexadecimal colon notation.In this 128 bits are divided into 8 sections each of the 2 bytes length.Two bytes in the hexadecimal requires 4 hexadecimal digits IPv6 specifies hexadecimal colon notation.


dotted hexadecimal notation

dotted hexadecimal notation

Address Space

It has much larger address space 2128 addresses are available.It has been divided into several categories.The category is defined by the few leftmost bits of the address called type prefix.It is variable in the length but designed such that no code is identical to any other part of the code.In this way there is no ambiguity when the address is given.


Type prefix for IPv6 address

Type prefix for IPv6 address


1.What is the difference between IPv4 and IPv6??

The IPv4 address is the 32 bit address i.e the length of the address is of 32 bit.Where as the IPv6 is the 128 bits address or 16 byte address.

2.What is NAT used for??

The NAT helps its users to have large number of the address for the private purpose use.It can be used for the household or the small scale firm use.

3.Explain the notations for the IPv4.

There are two types of the notations used in the IPv4

The address is represented as 32 bit..Each octet is termed as byte.


It is written in the form of the decimal notation with the decimal points separating the bytes.

Gate Syllabus-

  1. GATE Syllabus of Computer Science and Information Technology 2014
  2. GATE Syllabus of Electrical Engineering 2014
  3. GATE Syllabus of electronics and Telecommunication engineering
  4. Gate syllabus for Engineering science 2014

IES Syllabus-

1.IES Syllabus for Electronics and telecommunication

2.IES syllabus for General Ability


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2 Responses to IPv4 Addresses And IPv6 Addresses

  1. Dinesh says:

    IPV4 and IPV6 difference is most important terminology in this era, because all the concept are turning about the IPV6 from IPV4, so this article gives the neat and clear explanation about and difference of IPV4 and IPV6

  2. Soubarna Biswas says:

    Every body of use website addresses while searching for anything in the internet. But do you know it gets converted to a hexadecimal number. No! You don’t???? Then have a look on the article and know this amazing thing.

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