IP ADDRESSING AND IP CLASSES


 IP ADDRESSING

IP addressing is a mechanism which gives a unique number to every computer which is connected to network. every computer has different IP address so that we can easily differentiate various computers attached to network.

What is IP Address?


The full form IP address is Internet Protocol Address. IP address is a unique address of any computing devices like mobile phones , laptop , desktops , tablets etcetera .An Internet Protocol is a set of rules that govern Internet activity and facilitate completion of a variety of actions on the World Wide Web. 

An IP address is the unique 32 bit address which is given to every host computer which is connected in network. No two different computers should have same IP address.


There are two types of IP Addresses:


1. Static IP address: 

  •  A Static IP address: It will never change and it is a permanent Internet address.Static IP addresses are generally preferable for such uses as VOIP (Voice over Internet Protocol), online gaming, or any other purpose where users need to make it easy for other computers to locate and connect to them.
  • A static IP address is an IP address whose numbers represent a permanent address on the web. Every computer connected to the internet is assigned a unique number known as IP Address.
  •  A static IP address is an IP addresses whose value does not change. This is in contrast to a dynamic IP address which may change at any time. 
  • With a static IP address, a computer’s identity can be easily known by others, and one can easily connect with it.That way, for example, a website, email,server or other type of server connection can be hosted.


2. Dynamic IP address: 

  •  A dynamic IP address is a temporary address that is assigned each time a computer or device accesses the Internet. They are, in effect, borrowed from a pool of IP addresses that are shared among various computers. 
  • Since a limited number of static IP addresses are available, many ISPs reserve a portion of their assigned addresses for sharing among their subscribers in this way.
  • Unlike a static IP address that will be the same every time the user logs on, a dynamic IP address is different every time. 
  • With dynamic IP addressing, the IP address can be configured automatically. This method is much simpler and decrease management time and enables you to reuse IP addresses.
  • This is  commonly used for dial-up internet connections with internet service provider automatically assigning your computer a dynamic IP addresses


 Format of IP Address:


IP Address is a combination of 32 bits and each IP Address is a combination of numerical number ranging between 0 to 255. 


The IP address is usually expressed as four decimal numbers, each representing eight bits, separated by periods. This is called dot address and, more technically, as dotted quad notation. 


For example of IPv4 address: 89.90.255.1



Every IP Address is divided into two Parts:


1. Network Address: The part of an IP address that identifies the network.Each network must know its own address on the Internet and that of any other networks with which it communicates.

2. Host Address : The part of an IP address that identifies a host in a network. The host ID portion of an IP address, is the portion of the address used to identify hosts (any device requiring a Network Interface Card, such as a PC or networked printer) on the network.

Moreover, we can say that Network ID is your street name. And host id is your house number.The Network IP defines the range of IP and starting IP block , where as the host ID is specifically assigned to an NIC (Network Interface Card).

IP  Address Classes:

 There are five types of classes available:

1. Class A

2. Class B

3. Class C

4. Class D

5. Class E

 fig. IP Classes 

Every class is a combination of 32 bits included network address and host address and it divided into four octet(8 bits) as shown in fig. IP Classes. 

1. CLASS A

In class A, first bit is always starts from 0. 

Next 7 bits are Network address of IP Address.

Rest 24 bits are host address of IP Address.

Class A addresses are for large networks with many devices.

Range : 0 to 126 

It supports 16 millions hosts computers on each of 26 networks i.e only few networks, each with many hosts.

Note:127.0.0.0 is reserved in nature and it is a loopback address

2. CLASS B

In class B, first two bits are always starts from 10. 

Next 14 bits are Network address of IP Address.

Rest bits are host address of IP Address.

Range:  128 to 191 

 It supports 65000 hosts computers on each of 16000 networks i.e medium number of networks, each with a medium number of hosts.



3. CLASS C

In class C, first three bits are always starts from 110. 

Next 21 bits are Network address of IP Address.

Rest bits are host address of IP Address.

Range: 192 to 223

It supports 254 hosts computers on each of 2 million networks i.e many networks, each with a few hosts.


4. CLASS D

In class D, first four bits are always starts from 1110. 

Class D IP addresses were reserved for multicasting purposes.

These addresses begin with an octet in the 224-239 range.


5 CLASS E


Class E IP addresses are reserved for experimental use. 

The first octet of these addresses ranges between 240 and 255.

 

Special addresses:

There are various special IP addresses which are given below:


1. send to all : The IP address 255.255.255.255 = 11111111 11111111 11111111 11111111 is a broadcast address for sending something to all computers on the local network.


2. Send to all host computers : if  we place all 1’s in the  host portion  of an IP address then it will give a broadcast address for sending data to all hosts on the particular network.
for example: 128.23.255.255 = 10000000 00010111 11111111 11111111 would be the address to use to send something to all computers on the network with network ID 128.21


3. loop back address :  loop back address are normally use for checking the communication link between sender computer and receiver computer normally 127.0.0.1 = 01111111 00000000 00000000 0000001 is usually used for loop back purposes, such as testing communications software with both sender and receiver on the same computer. The data sent to this address appears as incoming data at this same address.

4. Boot up address: the address which is used by a computer to indicate itself at boot up is known as boot up address and the boot up address is 0.0.0.0