04-07-2012, 10:34 AM
Network Layer: Logical Addressing
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IPv4 ADDRESSES
An IPv4 address is a 32-bit address that uniquely and universally defines the connection of a device (for example, a computer or a router) to the Internet.
An IPv4 address is 32 bits long
The IPv4 addresses are unique and universal.
The address space of IPv4 is 232 or 4,294,967,296.
Classful Addressing
In classful addressing, the address space is divided into five classes:
A, B, C, D, and E.
Classless Addressing : Restrictions
The addresses in the block should be contiguous, one after another.
The number of addresses in a block must be power of 2 (1,2,4,8….)
The first address must be evenly divisible by the number of addresses.
First and Last Address in Block of Addresses
The first address in the block can be found by setting the rightmost 32 − n bits to 0s.
The last address in the block can be found by setting the rightmost 32 − n bits to 1s.
The number of addresses in the block can be found by using the formula 232−n