Ip address classes tutorial


Category: Computer Networks, gate study material for cse

Ip address classes

In this ip address classes based tutorial today we will learn about ip address related concepts such as ip address meaning, ip address classes, types of ip address ,classful addressing and loop back ip address and it’s use.

What is ip address meaning?

What are different  ip address classes ?

What is loop back ip address?

Ip address meaning

Ip address is also known as logical address, ip address meaning is assigning an address to a computer or host connected over a network. Ip address is the address assigned to each host present in a network. In IP addressing scheme two device can not have same IP address.

IP Address Specification

In ip addressing scheme two hosts cannot have the same IP Address.  An IP address is 32 bit binary number but generally for representation purpose IP address is represented as 4 values in decimal number system Each of the four represent the 8 bits in the range from 0 to 255 and separated by decimal point.

For example is a class C IP Address.

ip address classes

Ip address classes

There are five different ip address classes. Each of the ip address class has its specific range for defining the IP addressing. This types of ip addressing is also known as classful addressing.

Class A IP addresses begin with 1 to 126 in decimal.

Class B IP address in begin with 128 to 191 in decimal

Class C IP Address begun with 192 to 223 in decimal

Class D IP address begin with 224 to 139 in decimal

Class E IP Address begin with 240 to 254 in decimal.
To which class an IP address belongs, we can find it by examining the first four bits of the given IP Address.

Address begin with 127 are reserved for loop back ip address or internal testing on the local host. Address on a host points to itself.

Here we are describing the IP specification for each type of class as discussed above.
Class A: Class A is used for the large network.  8 bit network address and 24 bit host address. There are approximately 16 million hosts per network and maximum of 126 ( 27-2) Class A network can be defined.

Here remember one thing that 2  is subtracted  the reason is that IP address is reserved for use as default route and IP address is reserved for loop back function.  

Each class network can support maximum of 16,777,214( 224-2) hosts per network.  Here 2 is subtracted because all zeros is reserved to identify the network itself and all 1’s are reserved for broadcast address.

7 bits for network ID
24 bits for HOST ID

Class B:  Class B is used for Medium Network.  16 bit network address and 16 bit host address. There are approximately 65000 host per network and 16384 (214) class B network can be defined with up to (216-2) host per network.

14 bits for network ID
16 bits for HOST ID
Class C: Class C is used for Small Network.  24 bit network address and 8 bit host address there are approximately 250 hosts per network.

21 bits for network ID
8 bits for HOST ID
Class D: Class D is used for multicast messages. It means sending the messages on many host in a group.
28 bits for some sort of group addresses
Class E: This class is currently unused and it is reserved for some specific use in future.

28 bits
Unregistered IP Address: This is also important to know that for a private network that is not a part of internet. It is not necessary to register network address. 

For a network which is isolated from the internet then the network administrator can use the following IP address which are reserved for private network.

Class A:  to

Class B: to

Class C: to

The above IP address can be used by any one to set up internal IP Address for example Lab or Home network.

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