Thursday, 11 October 2012

IP Address


Introducing IP Addresses

Every device that s connected to the network using the TCP/IP protocol requires an IP address. Every individual in an organization has a unique employee ID by which the rest of the organization identifies him. An IP address is a 32 bit number that is unique for each device. A bit is the smallest unit of information on a computer. The value of a bit is either 0 or 1. All the other devices or computers on the network identify a device using the IP address.



This 32-bit binary IP address is represented as 4 octets, each consisting of 8 bits. Therefore, an IP address has 4 sets of decimal numbers separated with periods. An example of an IP address is 192.168.12.156.
For example, If a machine has an IP address of 10010100101000101001010010101011. It is split into 4 octets, such as:

Bits
1
0
0
1
0
1
0
0
Values
27=128
26=64
25=32
24=16
23=8
24=4
21=2
20=1

Values of Bits

Bits
1
0
0
1
0
1
0
0
Values
27=128
26=64
25=32
24=16
23=8
24=4
21=2
20=1
Multiple Values
128
0
0
16
0
4
0
0



Multiplied Values for Bits

The equivalent decimal value for the octet will be the addition of all the multiplied values. For the above octet 10010100, the decimal value will be 128+0+0+160+0+4+0+0 which is equal to 148.
  • 10010100 = 148
  • 10100010 = 162
  • 10010100 = 148
  • 10101011 = 171
The IP address of the device is 148.162.148.171.  If the bits in the octet consist of all 0s, the decimal value for the octet will be 0.  If the bits consist of 1, the decimal value of the octet will be 255.  So the decimals in the IP address will range form 0 to 255.

Classes of IP Addresses

Every IP address consists of two parts, the network, and host number. The Network Number identifies the network segment and host number identifies the actual devices. For Example, the network number is similar to the pin code of an area, while the host number is similar to the building number. The pin code is constant of the area while the building number changes. Similar the network number is constant of that segment, while the host number changes.

The IP protocol defines five classes of IP addresses:
  1. CLASS   A : –     Consists of an 8 bit network number and a 24 bit host number. Class A IP addresses range from the numbers 1 to 126. In the binary form, the first octet for Class A networks starts with 0. The IP address 0.0.0.0 is reserved and not included as a Class A IP address.
  2. CLASS   B : -     Consists of a 16 bit network number and a 16 bit host number. Class B IP address range from 128 to 191 decimals. The first octet for Class B network starts with 10.
  3. CLASS   C : -     Consists of a 24 bit network number and a 8 bit host number. Class C IP addresses range from 192 to 223 decimals. The first octet for Class C network starts with 110.
  4. CLASS   D : -     Consists of multicast addresses. Multicoasting is a procedure by whit the data packets can be sent to selected recipients over the network. The multicast addresses range from 224 to 239. The first octet from class d addresses starts with 1110. These addresses consist of 28 multicast address bits. Data in networks travel in the form of datagrams or data packets. If you need to send data packets to a number of recipients, you can use multicast IP addresses. You can use the Class D IP addresses to send data to many systems. Multicasting is generally used for transferring multimedia.
  5. CLASS  E  : -     Known as reserved IP addresses. These IP addresses range from 248 to 255. This class of IP addresses do not contain any hosts are available for them. The octet for this address starts with 1111.
HEXADECIMAL CONVERSION
The Hexadecimal system of conversion is another type of a numbering system followed by computers.
Decimal
Binary
Hexadecimal
0
0000
0
1
0001
1
2
0010
2
3
0011
3
4
0100
4
5
0101
5
6
0110
6
7
0111
7
8
1000
8
9
1001
9
10
1010
A
11
1011
B
12
1100
C
13
1101
D
14
1110
E
15
1111
F


Source : https://networkinghelps.wordpress.com/ip-addressing/