Different classes for IP addressing

Hello guys,

I have a few questions --

There are different classes for IP addressing

32-bit IP address with octate representation and maximum range from 0-255 representation for the same.

Like Class A - range from 1-126 - for the first octate with the format being

_____________________
|Network|Host|Host|Host|
------------------------------
This is for the class A IP addressing method and that for class B the range of the first octate is from 128-191.

________________________
|Network|Network|Host|Host|
----------------------------------


and for class C IP addressing method, the range of the first octane is 192-223.

____________________________
|Network|Network|Network|Host|
---------------------------------------

There is Class D (224-239) and Class E (240-255) , which can be used for further WAN and AI networks.

THE QUESTION IS

I want to know the reason why 127 is not considered when we have a transisiton from Class A and Class B networks?

and on what basis the range of these networks have been divided like the range of these networks specified as accoring to the Class?

with regards,
arun

range of first octate

ok guys ive already foundout that the IP - 127.0.0.0 (network address) - 127.0.0.1 to 127.255.255.255 is used for IP lookback, that is testing the data which is sent through the ethernet, so this IP address range between 127.0.0.1-127.255.255.255 cannot be used to put data in the communication channel but insted it is looped back to application which tests the channel.

with regards,
arun