The document explains IPv4 addressing, detailing classful and classless addressing techniques, including the classification of addresses into classes A, B, C, D, and E based on binary and decimal notation. It also covers address spaces, notations, the division of addresses into netid and hostid, and the rules for classless addressing. Additionally, it demonstrates how to identify classes and calculate first and last addresses within specified blocks.

2. CLASSFUL ADDRESSING
An IPv4 address is a 32-bit address that uniquely
and universally defines the connection of a
device to the internet.
(for example, a computer or a router)
Two devices on the internet can never have the
same address at the same time

3. Address spaces:- it is the total no of address
used by the protocol.
N bits a address
2n address
Address space ipv4 = 32 bit
N=32
Address spaces ipv4 = 232 = 4,294,967,296

4. Notations:-
(a)Binary notations:- in this ipv4 is displayed as
32 bits or 4 bytes.
01110101 10010101 00011101 11101010

5. (b) Dotted –decimal Notation:-
it is used to make ipv4 more compact and
easier to read.
10000000 00001011 00000011 00011111
128.11.3.31
(c) Hexadecimal Notation:- Each hexadecimal
digit is equivalent to four bits. This means
that 32 bit address has 8 hexadecimal digits.

6. Classful addressing :- in this address space is divided in
to five class.
Class A
Class B
Class C
Class D
Class E

7. HOW TO FIND CLASS OF AN ADDRESS
Binary Notation
Class A - 0
Class B - 10
Class C - 110
Class D -1110
Class E - 1111

8. Dotted-decimal:-
Class A = 0-127
Class B = 128-191
Class C = 192-223
Class D = 224-239
Class E = 240-255

9. Q1) FIND THE CLASS OF EACH ADDRESS DOTTED-DECIMAL
(a) 227.12.14.87 – class D
(b) 193.14.56.22 - class C
(c) 14.28.120.8 - class A
(d) 252.5.15.111 - class E

10. Q2) FIND THE CLASS EACH ADDRESS BINARY NOTATION
(A)00000001 00 ……………..  class A
(B)11000001 100……………  class C
(C)10100111 10…………….  class B
(D)11110011 100……………  class E

11. NETID & HOSTID
Only class A , B or C is divided in to netid and
hostid.
Class Byte 1 Byte2 Byte3 Byte4
Class A Netid Hostid Hostid Hostid
Class B Netid Netid Hostid Hostid
Class C Netid Netid Netid Hostid

12. CLASSLESS ADDRESSING
In this variable length blocks are used that belongs to no
class.
Restrictions :-
(1) address in a block must be contigous.
(2) No of address in a block must be a power of 2
(3) The first address must be evenly divisible by the no
of address.

13. Block first block second
205.16.37.32 16 = 24
205.16.37.33
205.16.37.34
205.16.37.35
…………….
…………….
205.16.37.47

14. . Mask in classless addressing :- Can take any
value from 0 to 32.
N=1
32-n=0
Slash/CIDR Notation
x.y.z.t/n

15. . First address in block can be found by setting
the right most 32-n bits to 0’s.
. Last address can found by setting the right
most 32-n bits to 1’s.
. No of address = 232-n

16. EX – ONE OF THE ADDRESS IS 205.16.37.39/28
FIND FIRST ,LAST AND TOTAL NO OF
ADDRESS
First address
11001101 00010000 00100101 00100111
11001101 00010000 00100101 00100000
205.16.37.32

17. . Last address - 205.16.37.39/28
11001101 00010000 00100101 00100111
11001101 00010000 00100101 00101111
205.16.37.47
. No of address= 24 = 16