The document discusses IP addressing and classes. It describes how IP addresses are made up of 32 bits divided into four 8-bit octets written in dotted-decimal format. It outlines the five classes of IP addresses - A, B, C, D and E - and their reserved first octet ranges and network/host bit allocations. It also covers subnet masking, network and broadcast addresses, and public and private IP address blocks.

2. Network Layer

3. IP Address IPv4
Network Host
32 Bits
10000011 01101100 01111010 11001100
8 Bits 8 Bits 8 Bits 8 Bits
131 108 122 204
8 Bits 8 Bits 8 Bits 8 Bits
. . .
dotted-decimal format
dotted-
Binary
format

4. IP Address Classes
Class A
50%
Class B
25%
Class C
12.5%
Other
Classes
12.5%
IP Classes

5. Class A addresses
0xxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx
Network Host Host Host
8 Bits 24 Bits
00000000 - 01111111
0 - 127
Any address that has a value between 1and 126 in the first octet is a
Class A address.

6. Class B addresses
10xxxxxx xxxxxxxx xxxxxxxx xxxxxxxx
Network Host Host
16 Bits 16 Bits
Network
10000000 - 10111111
128 - 191
Any address that starts with a value in the range of 128 to 191 in
the first octet is a Class Baddress.

7. Class C addresses
110xxxxx xxxxxxxx xxxxxxxx xxxxxxxx
Network Host
24 Bits 8 Bits
Network
11000000 - 11011111
192 -223
Network
If an address contains a number in the range of 192to 223 in the first
octet, it is a Class C address.

8. Class D addresses (multicasting )
xxxxxxxx xxxxxxxx xxxxxxxx
Network Host
4 Bits 28 Bits
xxxx1110
Host HostHost
11100000 - 11101111
224 - 239
An IP address that starts with a value in the range of 224 to 239 in
the first octet is a Class D address.

9. Class E Addresses ( research )
xxxxxxxx xxxxxxxx xxxxxxxx
Network Host
4 Bits 28 Bits
xxxx1111
Host HostHost
11110000 - 11111111
240 - 255
the first octet range for Class E addresses is 240 to 255.

10. IP Address Class IP Address Range ( first Octet
decimal value )
Class A 1 – 126 ( 00000001 – 01111110 )
Class B 128 – 191 ( 10000000 – 10111111 )
Class C 192 – 223 ( 11000000 – 11011111 )
Class D 224 – 239 ( 11100000 – 11101111 )
Class E 240 – 255 ( 11110000 – 11111111 )
127 ( 01111111 ) is a class A address reserved for loopback testing and can not
assigned for a network

11. Reserved IP Addresses – Network
Address
Network Host
32 Bits
N N H H
8 Bits 8 Bits 8 Bits 8 Bits
Network Address ( Host Bits = all ZEROs )

12. Reserved IP Addresses – Broadcast
Address
Network Host
32 Bits
N N H H
8 Bits 8 Bits 8 Bits 8 Bits
Broadcast Address ( Host Bits = all ONEs )

13. Subnet Mask ( Classful Addressing )
 Three Masks for Class A, Class B, andClass C
 255.0.0.0
 255.255.0.0
 255.255.255.0

14. ANDing with Mask
 Using the first mask (255.0.0.0)
 00001010.00100010.00010111.10000110: IP address
 11111111.00000000.00000000.00000000: network mask
 ANDing
 00001010.00000000.00000000.00000000
 10.0.0.0 is the network portion of the IP address

15.  Using the second mask (255.255.0.0)
 00001010.00100010.00010111.10000110: IP address
 11111111.11111111.00000000.00000000: network mask
 ANDing
 00001010.00100010.00000000.00000000
 10.34.0.0 is the network portion of the IP address

16. Public and Private Addresses
IP Address Class Internal Address Range
Class A 10.0.0.0 – 10.255.255.255
Class B 172.16.0.0 – 172.31.255.255
Class C 192.168.0.0 – 192.168.255.255