IP Address classes and default subnet mask

       IP address is a logical address, whose length is 32 bits. These 32 bits split into four part. These four part called as 'octet'. An octet has 8 bits. IP address can be represented in binary as well as in dotted decimal notation.
ex. Decimal 192.168.10.4

Class	Range	Default Subnet mask
Class A	1-126	255.0.0.0
Class B	128-191	255.255.0.0
Class C	192-223	255.255.255.0
Class D	224-239	For Multicasting
Class E	240-254	For Future use

       Class A, class B and class C IP addresses are used for assigning to computer system. Class D is used for multitasking and Class E is reserve for future use.